chore(deps): update module golang.org/x/crypto to v0.36.0 (#5)

Reviewed-on: #5
Co-authored-by: renovate[bot] <renovate@rgst.io>
Co-committed-by: renovate[bot] <renovate@rgst.io>

.gitignore

@@ -24,12 +24,11 @@ _testmain.go
 *.prof
 vendor/*
 
-# vendor management
-vendor/src/*
-vendor/pkg/*
 bin/*
+sigtool
 
 .??*.sw?
 *.pub
 *.key
 *.sig
+releases/*

.mise.toml

@@ -0,0 +1,2 @@
+[tools]
+golang = "1.24"

README.md

@@ -26,9 +26,21 @@ The sign, verify, encrypt, decrypt operations can use OpenSSH Ed25519 keys
 files to any recipient identified by their comment in `~/.ssh/authorized_keys`.
 
 ## How do I build it?
-With Go 1.13 and later:
+You need two things:
 
-    git clone https://github.com/opencoff/sigtool
+1. Protobuf compiler:
+
+   On Debian based systems: `apt install protobuf-compiler`
+
+   Consult your OS's package manager to install protobuf tools;
+   these are typically named 'protobuf' or 'protoc'.
+
+2. go 1.13+ toolchain
+
+
+Next, build sigtool:
+
+    git clone https://git.rgst.io/homelab/sigtool/v3
     cd sigtool
     make
 
@@ -89,6 +101,10 @@ e.g., to verify the signature of *archive.tar.gz* against
     sigtool verify /tmp/testkey.pub archive.sig archive.tar.gz
 
 
+You can also pass a public key as a string (instead of a file):
+
+    sigtool verify iF84Dymq/bAEnUMK6DRIHWAQDRD8FwDDDfsgFfzdjWM= archive.sig archive.tar.gz
+
 Note that signing and verifying can also work with OpenSSH ed25519
 keys.
 
@@ -140,19 +156,32 @@ recipient can decrypt using their private key.
 
 ### How is the file encryption done?
 The file encryption uses AES-GCM-256 in AEAD mode. The encryption uses
-a random 32-byte AES-256 key. This key is mixed in with the header checksum
+a random 32-byte AES-256 key. This root key is expanded via
-as a safeguard to protect the header against accidental or malicious corruption.
+HKDF-SHA256 into:
+
+   - AES-GCM-256 key (32 bytes)
+   - AES Nonce (12 bytes)
+   - HMAC-SHA-256 key (32 bytes)
+
+The input to the HKDF is the root-key, header-checksum ("salt") and
+a context string.
+
 The input is broken into chunks and each chunk is individually AEAD encrypted.
 The default chunk size is 4MB (4 * 1048576 bytes). Each chunk generates
-its own nonce from a global salt. The nonce is calculated as follows:
+its own nonce: the top-4 bytes of the nonce is the chunk-number. The
-
+actual chunk-length and EOF marker is used as additional data (the
-        - v1: SHA256 of the salt, the chunk length and the block number.
+"AD" of "AEAD").
-        - v2: Last 8 bytes of a 32-byte salt is the big-endian encoding of
-          the chunk-length and block number
-
 The last block has its most-signficant-bit set to 1 to denote EOF. Thus, the
 maximum chunk size is set to 1GB.
 
+We calculate a running hmac of the plaintext blocks; when sender
+identity is present, the final HMAC is signed via the sender's
+Ed25519 key. This signature is appended as the "trailer" (last 64
+bytes of the encrypted file are the Ed25519 signature).
+
+When sender identity is not present, the last bytes are random
+bytes.
+
 ### What is the public-key cryptography in sigtool?
 `sigtool` uses ephemeral Curve25519 keys to generate shared secrets
 between pairs of sender & one or more recipients. This pairwise shared
@@ -161,7 +190,7 @@ data-encryption key in AEAD mode. Thus, each recipient has their own
 individual encrypted key blob - that **only** they can decrypt.
 
 If the sender authenticates the encryption by providing their secret
-key, the data-encryption key is signed via Ed25519 and the signature
+key, the encryption key material is signed via Ed25519 and the signature
 is encrypted (using the data-encryption key) and stored in the
 header. If the sender opts to not authenticate, a "signature" of all
 zeroes is encrypted instead.
@@ -191,7 +220,7 @@ described as a protobuf file (sign/hdr.proto):
         uint32 chunk_size = 1;
         bytes  salt       = 2;
         bytes  pk         = 3;  // sender's ephemeral curve PK
-        bytes  sender_sig = 4;  // ed25519 signature of the key
+        bytes  sender     = 4;  // ed25519 signature of key material
         repeated wrapped_key keys = 5;
     }
 
@@ -201,6 +230,7 @@ described as a protobuf file (sign/hdr.proto):
      */
     message wrapped_key {
         bytes d_key = 1;
+        bytes nonce = 2;
     }
 ```
 
@@ -221,8 +251,8 @@ decryption.
 
 ### How is the private key protected?
 The Ed25519 private key is encrypted in AES-GCM-256 mode using a key
-derived from the user's pass-phrase. The user pass phrase is expanded via 
+derived from the user's pass-phrase. The user pass phrase is expanded via
-SHA256; this expanded pass phrase is fed to `scrypt()` to 
+SHA256; this expanded pass phrase is fed to `scrypt()` to
 generate a key-encryption-key.  In pseudo code, this operation looks
 like below:
 
@@ -251,6 +281,9 @@ etc.
 * `src/ssh.go`     contains code to parse SSH Ed25519 key files
 * `src/stream.go`  contains code that provides an `io.Reader` and `io.WriteCloser` interface
                    for encryption and decryption.
+* `tests.sh`       simple round trip test using the tool; this is in addition to the tests in
+                   `sign/`.
+
 
 The generated keys and signatures are proper YAML files and human
 readable.
@@ -263,6 +296,11 @@ Signatures on large files are calculated efficiently by reading them
 in memory mapped mode (```mmap(2)```) and hashing the file contents
 using SHA-512. The Ed25519 signature is calculated on the file-hash.
 
+### Tests
+The core library in `sign/` has extensive tests to verify signing and encryption.
+Additionally, a simple shell script `tests.sh` does a full roundtrip of tests
+using `sigtool`.
+
 ## Example of Keys, Signature
 
 ### Ed25519 Public Key

build

@@ -4,7 +4,7 @@
 #
 # - it tacks on a version number for use by the individual tools
 # - it supports git and mercurial version#
-# 
+#
 # NB:
 #   o the attempt at decoding dirty repo state for mercurial is
 #     borked. It doesn't know about untracked files
@@ -13,12 +13,13 @@
 #
 # License: GPLv2
 #
-Progs=".:sigtool"
+Progs="src:sigtool"
 
 # Relative path to protobuf sources
 # e.g. src/foo/a.proto
 Protobufs="internal/pb/hdr.proto"
 
+#set -x
 
 # -- DO NOT CHANGE ANYTHING AFTER THIS --
 
@@ -28,10 +29,10 @@ PWD=`pwd`
 Static=0
 Dryrun=0
 Prodver=""
+Repover=""
 Verbose=0
-
+Go=`which go`
-hostos=$(go env GOHOSTOS)       || exit 1
+Bindir=$PWD/bin
-hostcpu=$(go env GOHOSTARCH)    || exit 1
 
 die() {
     echo "$Z: $@" 1>&2
@@ -49,47 +50,56 @@ case $BASH_VERSION in
         ;;
 esac
 
+getvcs_version() {
+    local rev=
+    local prodv=
+    local git=`which git`
+    local hg=`which hg`
 
-# build a tool that runs on the host - if needed.
+    if [ -n "$git" ]; then
-hosttool() {
+        local xrev=$(git describe --always --dirty --long --abbrev=12) || exit 1
-    local tool=$1
+        rev="git:$xrev"
-    local bindir=$2
+        prodv=$(git tag --list | sort -V | tail -1)
-    local src=$3
+    elif [ -n "$hg" ]; then
-
+        local xrev=$(hg id --id) || exit 1
-    local p=$(type -P $tool)
+        local brev=${xrev%+}
-    if [ -n "$p" ]; then
+        if [ "$brev" != "$xrev" ]; then
-        echo $p
+            rev="hg:${brev}-dirty"
-        return 0
+        else
+            rev="hg:${brev}"
+        fi
+        prodv=$(hg log -r "branch(stable) and tag()" -T "{tags}\n" | sort -V | tail -1)
+    else
+        warn "no git or hg found; can't get VCS info"
+        rev="UNKNOWN-VER"
     fi
 
-    # from here - we want this dir to find all build artifacts
+    [ -n "$Prodver" ] && prodv=$Prodver
-    PATH=$PATH:$bindir
-    export PATH
 
-    p=$bindir/$tool
+    echo "$rev $prodv"
-    if [ -x $p ]; then
-        echo $p
-        return 0
-    fi
-
-    # build it and stash it in the hostdir
-    echo "Building tool $tool from $src .."
-    $e go get -d      $src || exit 1
-    $e go build -o $p $src || exit 1
-    echo $p
     return 0
 }
 
+read -r Repover Prodver <<< $(getvcs_version)
+
 
 usage() {
+    declare -a progv=($Progs)
+    declare n=${#progv[@]}
+    declare pstr=
+
+    for ((i=0; i < n; i++)); do
+        local ent=${progv[$i]}
+        local dir=${ent%%:*}
+        local tool=${ent##*:}
+        pstr=$(printf "$pstr\n\t%s $Prodver $Repover (from ./%s)" $tool $dir)
+    done
 
     cat <<EOF
 $0 - A Go production build tool that adds git-repository information,
 product version, build-timestamp etc. It supports cross-compilation,
 static linking and generating protobuf output.
 
-If needed, it uses the gogo-slick protobuf compiler [github.com/gogo/protobuf].
-
 Build output is in bin/\$OS-\$CPU for a given OS, CPU combination.
 
 Usage: $0
@@ -98,13 +108,14 @@ Usage: $0
 Where OS-ARCH denotes one of the valid OS, ARCH combinations supported by 'go'.
 And, PROGS is one or more go programs.
 
-With no arguments, $0 builds: $Progs (source in ./src/)
+With no arguments, $0 builds: $pstr
 
 The repository's latest tag is used as the default version of the software being
-built.
+built. The current repository version is $Repover.
 
 Options:
     -h, --help          Show this help message and quit
+    -b D, --bindir=D    Put the binaries in the directory 'D' [$Bindir]
     -s, --static        Build a statically linked binary [False]
     -V N, --version=N   Use 'N' as the product version string [$Prodver]
     -a X, --arch=X      Cross compile for OS-CPU 'X' [$hostos-$hostcpu]
@@ -112,14 +123,16 @@ Options:
     -t, --test          Run "go test" on modules named on the command line [False]
     -v, --verbose       Build verbosely (adds "-v" to go tooling) [False]
     --vet               Run "go vet" on modules named on the command line [False]
+    --mod               Run "go mod ..." [False]
+    --go=G              Use Go in 'G' [$Go]
     -x                  Run in debug/trace mode [False]
+    --print-arch        Print the target architecture and exit
 EOF
 
     exit 0
 }
 
 host=`uname|tr '[A-Z]' '[a-z]'`
-export GO15VENDOREXPERIMENT=1
 
 declare -A oses
 declare -A cpus
@@ -180,13 +193,23 @@ do
         --arch=*)
             Arch=$ac_optarg
             ;;
+
         -a|--arch)
             ac_prev=Arch
             ;;
 
+        -b|--bindir)
+            ac_prev=Bindir
+            ;;
+
+        --bindir=*)
+            Bindir=$ac_optarg
+            ;;
+
         --version=*)
             Prodver=$ac_optarg
             ;;
+
         --test|-t)
             Tool=test
             ;;
@@ -195,9 +218,14 @@ do
             Tool=vet
             ;;
 
+        --mod)
+            Tool=mod
+            ;;
+
         -V|--version)
             ac_prev=Prodver
             ;;
+
         -v|--verbose)
             Verbose=1
             ;;
@@ -214,6 +242,10 @@ do
             set -x
             ;;
 
+        --go-root=*)
+            GoRoot=$ac_optarg
+            ;;
+
         --print-arch)
             Printarch=1
             ;;
@@ -229,11 +261,81 @@ do
             ;;
   esac
 done
+
 [ $Dryrun  -gt 0 ] && e=echo
 
 # let every error abort
 set -e
 
+# build a tool that runs on the host - if needed.
+hosttool() {
+    local tool=$1
+    local bindir=$2
+    local src=$3
+
+    p=$bindir/$tool
+    if [ -x $p ]; then
+        return 0
+    fi
+
+    local tmpdir=/tmp/$tool.$$
+    mkdir $tmpdir || die "can't make $tmpdir"
+
+    # since go1.20 - install uses env vars to decide where to put
+    # build artifacts. Why are all the google tooling so bloody dev
+    # hostile! WTF is wrong with command line args?!
+    export GOBIN=$bindir
+
+    # build it and stash it in the hostdir
+    echo "Building tool $tool from $src .."
+    (
+       cd $tmpdir
+       $e $Go install  $src@latest || die "can't install $tool"
+    )
+    $e rm -rf  $tmpdir
+
+    return 0
+}
+
+# protobuf gen
+buildproto() {
+    local pbgo=protoc-gen-go
+    local vtgo=protoc-gen-go-vtproto
+    local vtgo_src=github.com/planetscale/vtprotobuf/cmd/protoc-gen-go-vtproto
+    local pc
+    local args="$*"
+
+    local pgen=$(type -p protoc)
+    local gogen=$(type -p $pbgo)
+    local vt=$Hostbindir/$vtgo
+
+    [ -z $pgen  ] && die "install protoc tools"
+    [ -z $gogen ] && die "install protoc-gen-go"
+
+    # now install the vtproto generator
+    hosttool $vtgo $Hostbindir $vtgo_src
+
+    for f in $args; do
+        local dn=$(dirname $f)
+        local bn=$(basename $f .proto)
+
+
+        $e $pgen  \
+            --go_out=. --plugin protoc-gen-go=$gogen \
+            --go-vtproto_out=. --plugin protoc-gen-go-vtproto="$vt" \
+            --go-vtproto_opt=features=marshal+unmarshal+size  \
+             $f || die "can't generate protobuf output for $f .."
+    done
+
+    return 0
+}
+
+
+# the rest has to execute in the context of main shell (not funcs)
+
+hostos=$($Go  env GOHOSTOS)      || exit 1
+hostcpu=$($Go env GOHOSTARCH)    || exit 1
+
 # This fragment can't be in a function - since it exports several vars
 if [ -n "$Arch" ]; then
     ox=${Arch%%-*}
@@ -285,72 +387,25 @@ fi
 
 
 # This is where build outputs go
-Bindir=$PWD/bin/$cross
+Outdir=$Bindir/$cross
-Hostbindir=$PWD/bin/$hostos-$hostcpu
+Hostbindir=$Bindir/$hostos-$hostcpu
+export PATH=$Hostbindir:$PATH
 
-[ -d $Bindir ]     || mkdir -p $Bindir
+[ -d $Outdir ]     || mkdir -p $Outdir
 [ -d $Hostbindir ] || mkdir -p $Hostbindir
 
-# Get git/hg version info for the build
-if [ -d "./.hg" ]; then
-    xrev=$(hg id --id) || exit 1
-    brev=${xrev%+}
-    if [ "$brev" != "$xrev" ]; then
-        rev="hg:${brev}-dirty"
-    else
-        rev="hg:${brev}"
-    fi
-    if [ -z "$Prodver" ]; then
-        Prodver=$(hg log -r "branch(stable) and tag()" -T "{tags}\n" | tail -1)
-    fi
-elif [ -d "./.git" ]; then
-    xrev=$(git describe --always --dirty --long --abbrev=12) || exit 1
-    rev="git:$xrev"
-    if [ -z "$Prodver" ]; then
-        Prodver=$(git tag --list | tail -1)
-    fi
-else
-    rev="UNKNOWN-VER"
-    echo "$0: Can't find version info" 1>&2
-fi
-
 
 # Do Protobufs if needed
 if [ -n "$Protobufs" ]; then
     set +e
-    slick=$Hostbindir/protoc-gen-gogoslick
+    buildproto $Protobufs
-    slicksrc=github.com/gogo/protobuf/protoc-gen-gogoslick
-    for pc in protoc protoc-c; do
-        pc=`which $pc`
-        [ -n "$pc" ] && break
-    done
-
-    [ -z "$pc" ] && die "Need 'protoc' for building .."
-
-    slick=$(hosttool protoc-gen-gogoslick $Hostbindir $slicksrc) || exit 1
-    #if [ ! -f $slick ]; then
-    #   echo "Building $slick .."
-    #   $e go build -o $slick github.com/gogo/protobuf/protoc-gen-gogoslick || exit 1
-    #i
-
-    export PATH=$PATH:$Hostbindir
-
-    for f in $Protobufs; do
-        dn=$(dirname $f)
-        bn=$(basename $f .proto)
-        of=$dn/${bn}.pb.go
-        if [ $f -nt $of ]; then
-            echo "Running $pc .."
-            $e $pc --gogoslick_out=. $f || exit 1
-        fi
-    done
     set -e
 fi
 
-repover="main.RepoVersion=$rev"
+# Get git/hg version info for the build
+repover="main.RepoVersion=$Repover"
 prodver="main.ProductVersion=$Prodver"
-date="main.Buildtime=`date -u '+%Y-%m-%dT%H:%M.%SZ'`"
+ldflags="-ldflags \"-X $repover -X $prodver $ldflags -buildid=\""
-ldflags="-ldflags \"-X $repover -X $prodver -X $date $ldflags\""
 vflag=""
 
 [ $Verbose -gt 0 ] && vflag="-v"
@@ -358,12 +413,17 @@ vflag=""
 case $Tool in
     test)
         set -- $args
-        $e go test $vflag "$@"
+        $e $Go test $vflag "$@"
         ;;
 
     vet)
         set -- $args
-        $e go vet $vflag "$@"
+        $e $Go vet $vflag "$@"
+        ;;
+
+    mod)
+        set -- $args
+        $e $Go mod $vflag "$@"
         ;;
 
     *) # Default is to build programs
@@ -374,9 +434,11 @@ case $Tool in
             all="$@"
         fi
 
-        echo "Building $Prodver ($rev), $cross $msg .."
+        [ -z "$all" ] && die "No programs specified. Try '$Z --help'"
 
-        for p in $all; do 
+        echo "Building $Prodver ($Repover), $cross $msg .."
+
+        for p in $all; do
             if echo $p | grep -q ':' ; then
                 out=${p##*:}
                 dir=${p%%:*}
@@ -384,8 +446,15 @@ case $Tool in
                 out=$p
                 dir=$p
             fi
+
+            # Add .exe suffix to out if needed
+            if [ "$GOOS" = "windows" ]; then
+                base=${out%%.exe}
+                out="${base}.exe"
+            fi
+
             echo "   $dir: $out .. "
-            $e eval go build $vflag -o $Bindir/$out $isuffix "$ldflags" ./$dir || exit 1
+            $e eval $Go build $vflag -trimpath -o $Outdir/$out $isuffix "$ldflags" ./$dir || exit 1
         done
         ;;
 esac

go.mod

@@ -1,14 +1,25 @@
-module github.com/opencoff/sigtool
+module git.rgst.io/homelab/sigtool/v3
 
-go 1.17
+go 1.24.0
 
 require (
 	github.com/dchest/bcrypt_pbkdf v0.0.0-20150205184540-83f37f9c154a
-	github.com/gogo/protobuf v1.3.2
+	github.com/opencoff/go-fio v0.5.14
-	github.com/opencoff/go-utils v0.4.1
+	github.com/opencoff/go-mmap v0.1.5
-	github.com/opencoff/pflag v0.5.0
+	github.com/opencoff/go-utils v1.0.2
-	golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9
+	github.com/opencoff/pflag v1.0.7
-	gopkg.in/yaml.v2 v2.2.7
+	github.com/planetscale/vtprotobuf v0.6.0
+	golang.org/x/crypto v0.36.0
+	google.golang.org/protobuf v1.36.5
+	gopkg.in/yaml.v3 v3.0.1
 )
 
-require golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f // indirect
+require (
+	github.com/pkg/xattr v0.4.10 // indirect
+	github.com/puzpuzpuz/xsync/v3 v3.5.1 // indirect
+	golang.org/x/sys v0.31.0 // indirect
+	golang.org/x/term v0.30.0 // indirect
+)
+
+//replace github.com/opencoff/go-mmap => ../go-mmap
+//replace github.com/opencoff/go-utils => ../go-utils

go.sum

@@ -1,44 +1,39 @@
 github.com/dchest/bcrypt_pbkdf v0.0.0-20150205184540-83f37f9c154a h1:saTgr5tMLFnmy/yg3qDTft4rE5DY2uJ/cCxCe3q0XTU=
 github.com/dchest/bcrypt_pbkdf v0.0.0-20150205184540-83f37f9c154a/go.mod h1:Bw9BbhOJVNR+t0jCqx2GC6zv0TGBsShs56Y3gfSCvl0=
-github.com/gogo/protobuf v1.3.2 h1:Ov1cvc58UF3b5XjBnZv7+opcTcQFZebYjWzi34vdm4Q=
+github.com/google/go-cmp v0.5.5 h1:Khx7svrCpmxxtHBq5j2mp/xVjsi8hQMfNLvJFAlrGgU=
-github.com/gogo/protobuf v1.3.2/go.mod h1:P1XiOD3dCwIKUDQYPy72D8LYyHL2YPYrpS2s69NZV8Q=
+github.com/google/go-cmp v0.5.5/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
-github.com/kisielk/errcheck v1.5.0/go.mod h1:pFxgyoBC7bSaBwPgfKdkLd5X25qrDl4LWUI2bnpBCr8=
+github.com/opencoff/go-fio v0.5.14 h1:PGi4XLLO4RSuc3m5exY0G2vweov6w3UThhScehBfM8c=
-github.com/kisielk/gotool v1.0.0/go.mod h1:XhKaO+MFFWcvkIS/tQcRk01m1F5IRFswLeQ+oQHNcck=
+github.com/opencoff/go-fio v0.5.14/go.mod h1:hoSySYpavRnfQUsxzUgadk31kYiNQhMDvA2MObsXKf8=
-github.com/opencoff/go-utils v0.4.1 h1:Ke4Q1Tl2GKMI+dwleuPNHH713ngRiNMOFIkymncHqXg=
+github.com/opencoff/go-mmap v0.1.5 h1:RKPtevC4mOW5bi9skBPPo4nFTIH4lVWAL20Tff+FjLg=
-github.com/opencoff/go-utils v0.4.1/go.mod h1:c+7QUAiCCHcNH6OGvsZ0fviG7cgse8Y3ucg+xy7sGXM=
+github.com/opencoff/go-mmap v0.1.5/go.mod h1:y/6Jk/tDUc00k3oSQpiJX++20Nw7xFSlc5kLkhGnRXw=
-github.com/opencoff/pflag v0.5.0 h1:kK3cSTlGj0fHby/PoFzHkf+Jx3PdiACJwzYDWEWlEKQ=
+github.com/opencoff/go-utils v1.0.2 h1:BANRL8ZxgHpuo8gQBAzT3M9Im3aNFhaWW28jhc86LNs=
-github.com/opencoff/pflag v0.5.0/go.mod h1:mTLzGGUGda1Av3d34iAJlh0JIlRxmFZtmc6qoWPspK0=
+github.com/opencoff/go-utils v1.0.2/go.mod h1:eZkEVQVzNfuE8uGepyhscMsqcXq7liGbBHYYwgYaoy8=
-github.com/yuin/goldmark v1.1.27/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+github.com/opencoff/pflag v1.0.7 h1:o5cQIuX75bDcdJ6AXl68gzpA72a3CJ2MPStaMnEuwi4=
-github.com/yuin/goldmark v1.2.1/go.mod h1:3hX8gzYuyVAZsxl0MRgGTJEmQBFcNTphYh9decYSb74=
+github.com/opencoff/pflag v1.0.7/go.mod h1:2bXtpAD/5h/2LarkbsRwiUxqnvB1nZBzn9Xjad1P41A=
-golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+github.com/pkg/xattr v0.4.10 h1:Qe0mtiNFHQZ296vRgUjRCoPHPqH7VdTOrZx3g0T+pGA=
-golang.org/x/crypto v0.0.0-20190618222545-ea8f1a30c443/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
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-golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI=
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-golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9 h1:psW17arqaxU48Z5kZ0CQnkZWQJsqcURM6tKiBApRjXI=
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-golang.org/x/crypto v0.0.0-20200622213623-75b288015ac9/go.mod h1:LzIPMQfyMNhhGPhUkYOs5KpL4U8rLKemX1yGLhDgUto=
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-golang.org/x/mod v0.2.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
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-golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA=
+golang.org/x/crypto v0.35.0 h1:b15kiHdrGCHrP6LvwaQ3c03kgNhhiMgvlhxHQhmg2Xs=
-golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
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-golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/crypto v0.36.0 h1:AnAEvhDddvBdpY+uR+MyHmuZzzNqXSe/GvuDeob5L34=
-golang.org/x/net v0.0.0-20200226121028-0de0cce0169b/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
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-golang.org/x/net v0.0.0-20201021035429-f5854403a974/go.mod h1:sp8m0HH+o8qH0wwXwYZr8TS3Oi6o0r6Gce1SSxlDquU=
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-golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
-golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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-golang.org/x/sync v0.0.0-20201020160332-67f06af15bc9/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
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-golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.31.0/go.mod h1:BJP2sWEmIv4KK5OTEluFJCKSidICx8ciO85XgH3Ak8k=
-golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.29.0 h1:L6pJp37ocefwRRtYPKSWOWzOtWSxVajvz2ldH/xi3iU=
-golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f h1:+Nyd8tzPX9R7BWHguqsrbFdRx3WQ/1ib8I44HXV5yTA=
+golang.org/x/term v0.29.0/go.mod h1:6bl4lRlvVuDgSf3179VpIxBF0o10JUpXWOnI7nErv7s=
-golang.org/x/sys v0.0.0-20200930185726-fdedc70b468f/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/term v0.30.0 h1:PQ39fJZ+mfadBm0y5WlL4vlM7Sx1Hgf13sMIY2+QS9Y=
-golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/term v0.30.0/go.mod h1:NYYFdzHoI5wRh/h5tDMdMqCqPJZEuNqVR5xJLd/n67g=
-golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
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-golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
-golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
-golang.org/x/tools v0.0.0-20200619180055-7c47624df98f/go.mod h1:EkVYQZoAsY45+roYkvgYkIh4xh/qjgUK9TdY2XT94GE=
-golang.org/x/tools v0.0.0-20210106214847-113979e3529a/go.mod h1:emZCQorbCU4vsT4fOWvOPXz4eW1wZW4PmDk9uLelYpA=
-golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
 golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/protobuf v1.36.5 h1:tPhr+woSbjfYvY6/GPufUoYizxw1cF/yFoxJ2fmpwlM=
+google.golang.org/protobuf v1.36.5/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v2 v2.2.7 h1:VUgggvou5XRW9mHwD/yXxIYSMtY0zoKQf/v226p2nyo=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
-gopkg.in/yaml.v2 v2.2.7/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/pb/hdr.proto

@@ -1,13 +1,8 @@
 syntax="proto3";
 
-//import "gogoproto/gogo.proto"
 
-package pb;
+option go_package = "internal/pb";
 
-//option (gogoproto.marshaler_all) = true;
-//option (gogoproto.sizer_all) = true;
-//option (gogoproto.unmarshaler_all) = true;
-//option (gogoproto.goproto_getters_all) = false;
 
 /*
  * Every encrypted file starts with a header describing the
@@ -16,11 +11,11 @@ package pb;
  * protobuf format before writing to disk.
  */
 message header {
-	uint32 chunk_size  = 1;	// encryption block size
+    uint32 chunk_size  = 1; // encryption block size
-	bytes  salt		   = 2;	// master salt (nonces are derived from this)
+    bytes  salt        = 2; // master salt (nonces are derived from this)
-	bytes  pk		   = 3;	// ephemeral curve PK
+    bytes  pk          = 3; // ephemeral curve PK
-	bytes  sender_sign = 4;  // signature block of sender
+    bytes  sender      = 4; // sender signed artifacts
-	repeated wrapped_key keys = 5;  // list of wrapped receiver blocks
+    repeated wrapped_key keys  = 5; // list of wrapped receiver blocks
 }
 
 /*
@@ -28,5 +23,7 @@ message header {
  * key. WrappedKey describes such a wrapped key.
  */
 message wrapped_key {
-	bytes d_key = 1;	// encrypted data key
+    bytes d_key = 1;    // encrypted data key
+    bytes nonce = 2;    // nonce used for encryption
 }
+

internal/pb/hdr_vtproto.pb.go

@@ -0,0 +1,512 @@
+// Code generated by protoc-gen-go-vtproto. DO NOT EDIT.
+// protoc-gen-go-vtproto version: v0.6.0
+// source: internal/pb/hdr.proto
+
+package pb
+
+import (
+	fmt "fmt"
+	protohelpers "github.com/planetscale/vtprotobuf/protohelpers"
+	protoimpl "google.golang.org/protobuf/runtime/protoimpl"
+	io "io"
+)
+
+const (
+	// Verify that this generated code is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(20 - protoimpl.MinVersion)
+	// Verify that runtime/protoimpl is sufficiently up-to-date.
+	_ = protoimpl.EnforceVersion(protoimpl.MaxVersion - 20)
+)
+
+func (m *Header) MarshalVT() (dAtA []byte, err error) {
+	if m == nil {
+		return nil, nil
+	}
+	size := m.SizeVT()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBufferVT(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *Header) MarshalToVT(dAtA []byte) (int, error) {
+	size := m.SizeVT()
+	return m.MarshalToSizedBufferVT(dAtA[:size])
+}
+
+func (m *Header) MarshalToSizedBufferVT(dAtA []byte) (int, error) {
+	if m == nil {
+		return 0, nil
+	}
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.unknownFields != nil {
+		i -= len(m.unknownFields)
+		copy(dAtA[i:], m.unknownFields)
+	}
+	if len(m.Keys) > 0 {
+		for iNdEx := len(m.Keys) - 1; iNdEx >= 0; iNdEx-- {
+			size, err := m.Keys[iNdEx].MarshalToSizedBufferVT(dAtA[:i])
+			if err != nil {
+				return 0, err
+			}
+			i -= size
+			i = protohelpers.EncodeVarint(dAtA, i, uint64(size))
+			i--
+			dAtA[i] = 0x2a
+		}
+	}
+	if len(m.Sender) > 0 {
+		i -= len(m.Sender)
+		copy(dAtA[i:], m.Sender)
+		i = protohelpers.EncodeVarint(dAtA, i, uint64(len(m.Sender)))
+		i--
+		dAtA[i] = 0x22
+	}
+	if len(m.Pk) > 0 {
+		i -= len(m.Pk)
+		copy(dAtA[i:], m.Pk)
+		i = protohelpers.EncodeVarint(dAtA, i, uint64(len(m.Pk)))
+		i--
+		dAtA[i] = 0x1a
+	}
+	if len(m.Salt) > 0 {
+		i -= len(m.Salt)
+		copy(dAtA[i:], m.Salt)
+		i = protohelpers.EncodeVarint(dAtA, i, uint64(len(m.Salt)))
+		i--
+		dAtA[i] = 0x12
+	}
+	if m.ChunkSize != 0 {
+		i = protohelpers.EncodeVarint(dAtA, i, uint64(m.ChunkSize))
+		i--
+		dAtA[i] = 0x8
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *WrappedKey) MarshalVT() (dAtA []byte, err error) {
+	if m == nil {
+		return nil, nil
+	}
+	size := m.SizeVT()
+	dAtA = make([]byte, size)
+	n, err := m.MarshalToSizedBufferVT(dAtA[:size])
+	if err != nil {
+		return nil, err
+	}
+	return dAtA[:n], nil
+}
+
+func (m *WrappedKey) MarshalToVT(dAtA []byte) (int, error) {
+	size := m.SizeVT()
+	return m.MarshalToSizedBufferVT(dAtA[:size])
+}
+
+func (m *WrappedKey) MarshalToSizedBufferVT(dAtA []byte) (int, error) {
+	if m == nil {
+		return 0, nil
+	}
+	i := len(dAtA)
+	_ = i
+	var l int
+	_ = l
+	if m.unknownFields != nil {
+		i -= len(m.unknownFields)
+		copy(dAtA[i:], m.unknownFields)
+	}
+	if len(m.Nonce) > 0 {
+		i -= len(m.Nonce)
+		copy(dAtA[i:], m.Nonce)
+		i = protohelpers.EncodeVarint(dAtA, i, uint64(len(m.Nonce)))
+		i--
+		dAtA[i] = 0x12
+	}
+	if len(m.DKey) > 0 {
+		i -= len(m.DKey)
+		copy(dAtA[i:], m.DKey)
+		i = protohelpers.EncodeVarint(dAtA, i, uint64(len(m.DKey)))
+		i--
+		dAtA[i] = 0xa
+	}
+	return len(dAtA) - i, nil
+}
+
+func (m *Header) SizeVT() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	if m.ChunkSize != 0 {
+		n += 1 + protohelpers.SizeOfVarint(uint64(m.ChunkSize))
+	}
+	l = len(m.Salt)
+	if l > 0 {
+		n += 1 + l + protohelpers.SizeOfVarint(uint64(l))
+	}
+	l = len(m.Pk)
+	if l > 0 {
+		n += 1 + l + protohelpers.SizeOfVarint(uint64(l))
+	}
+	l = len(m.Sender)
+	if l > 0 {
+		n += 1 + l + protohelpers.SizeOfVarint(uint64(l))
+	}
+	if len(m.Keys) > 0 {
+		for _, e := range m.Keys {
+			l = e.SizeVT()
+			n += 1 + l + protohelpers.SizeOfVarint(uint64(l))
+		}
+	}
+	n += len(m.unknownFields)
+	return n
+}
+
+func (m *WrappedKey) SizeVT() (n int) {
+	if m == nil {
+		return 0
+	}
+	var l int
+	_ = l
+	l = len(m.DKey)
+	if l > 0 {
+		n += 1 + l + protohelpers.SizeOfVarint(uint64(l))
+	}
+	l = len(m.Nonce)
+	if l > 0 {
+		n += 1 + l + protohelpers.SizeOfVarint(uint64(l))
+	}
+	n += len(m.unknownFields)
+	return n
+}
+
+func (m *Header) UnmarshalVT(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return protohelpers.ErrIntOverflow
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: Header: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: Header: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 0 {
+				return fmt.Errorf("proto: wrong wireType = %d for field ChunkSize", wireType)
+			}
+			m.ChunkSize = 0
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				m.ChunkSize |= uint32(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Salt", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Salt = append(m.Salt[:0], dAtA[iNdEx:postIndex]...)
+			if m.Salt == nil {
+				m.Salt = []byte{}
+			}
+			iNdEx = postIndex
+		case 3:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Pk", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Pk = append(m.Pk[:0], dAtA[iNdEx:postIndex]...)
+			if m.Pk == nil {
+				m.Pk = []byte{}
+			}
+			iNdEx = postIndex
+		case 4:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Sender", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Sender = append(m.Sender[:0], dAtA[iNdEx:postIndex]...)
+			if m.Sender == nil {
+				m.Sender = []byte{}
+			}
+			iNdEx = postIndex
+		case 5:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Keys", wireType)
+			}
+			var msglen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				msglen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if msglen < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			postIndex := iNdEx + msglen
+			if postIndex < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Keys = append(m.Keys, &WrappedKey{})
+			if err := m.Keys[len(m.Keys)-1].UnmarshalVT(dAtA[iNdEx:postIndex]); err != nil {
+				return err
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := protohelpers.Skip(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.unknownFields = append(m.unknownFields, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}
+func (m *WrappedKey) UnmarshalVT(dAtA []byte) error {
+	l := len(dAtA)
+	iNdEx := 0
+	for iNdEx < l {
+		preIndex := iNdEx
+		var wire uint64
+		for shift := uint(0); ; shift += 7 {
+			if shift >= 64 {
+				return protohelpers.ErrIntOverflow
+			}
+			if iNdEx >= l {
+				return io.ErrUnexpectedEOF
+			}
+			b := dAtA[iNdEx]
+			iNdEx++
+			wire |= uint64(b&0x7F) << shift
+			if b < 0x80 {
+				break
+			}
+		}
+		fieldNum := int32(wire >> 3)
+		wireType := int(wire & 0x7)
+		if wireType == 4 {
+			return fmt.Errorf("proto: WrappedKey: wiretype end group for non-group")
+		}
+		if fieldNum <= 0 {
+			return fmt.Errorf("proto: WrappedKey: illegal tag %d (wire type %d)", fieldNum, wire)
+		}
+		switch fieldNum {
+		case 1:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field DKey", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.DKey = append(m.DKey[:0], dAtA[iNdEx:postIndex]...)
+			if m.DKey == nil {
+				m.DKey = []byte{}
+			}
+			iNdEx = postIndex
+		case 2:
+			if wireType != 2 {
+				return fmt.Errorf("proto: wrong wireType = %d for field Nonce", wireType)
+			}
+			var byteLen int
+			for shift := uint(0); ; shift += 7 {
+				if shift >= 64 {
+					return protohelpers.ErrIntOverflow
+				}
+				if iNdEx >= l {
+					return io.ErrUnexpectedEOF
+				}
+				b := dAtA[iNdEx]
+				iNdEx++
+				byteLen |= int(b&0x7F) << shift
+				if b < 0x80 {
+					break
+				}
+			}
+			if byteLen < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			postIndex := iNdEx + byteLen
+			if postIndex < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if postIndex > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.Nonce = append(m.Nonce[:0], dAtA[iNdEx:postIndex]...)
+			if m.Nonce == nil {
+				m.Nonce = []byte{}
+			}
+			iNdEx = postIndex
+		default:
+			iNdEx = preIndex
+			skippy, err := protohelpers.Skip(dAtA[iNdEx:])
+			if err != nil {
+				return err
+			}
+			if (skippy < 0) || (iNdEx+skippy) < 0 {
+				return protohelpers.ErrInvalidLength
+			}
+			if (iNdEx + skippy) > l {
+				return io.ErrUnexpectedEOF
+			}
+			m.unknownFields = append(m.unknownFields, dAtA[iNdEx:iNdEx+skippy]...)
+			iNdEx += skippy
+		}
+	}
+
+	if iNdEx > l {
+		return io.ErrUnexpectedEOF
+	}
+	return nil
+}

internal/pb/helpers.go

@@ -0,0 +1,16 @@
+// helper routines to maintain backwards compat with gogo
+
+package pb
+
+
+func (m *Header) Size() int {
+	return m.SizeVT()
+}
+
+func (m *Header) MarshalTo(buf []byte) (int, error) {
+	return m.MarshalToVT(buf)
+}
+
+func (m *Header) Unmarshal(buf []byte) error {
+	return m.UnmarshalVT(buf)
+}

mk-rel.sh

@@ -0,0 +1,54 @@
+#! /usr/bin/env bash
+
+Z=`basename $0`
+die() {
+    echo "$Z: $@" 1>&2
+    exit 1
+}
+
+warn() {
+    echo "$Z: $@" 1>&2
+}
+
+case $BASH_VERSION in
+    4.*|5.*) ;;
+
+    *) die "I need bash 4.x to run!"
+        ;;
+esac
+
+Rel=$PWD/releases
+Bindir=$Rel/bin
+mkdir -p $Bindir || die "can't make $Bindir"
+
+pkgit() {
+    local os=$1
+    local cpu=$2
+    local rev=$3
+    local arch="$os-$cpu"
+    local tgz="$Rel/sigtool-${rev}_${arch}.tar.gz"
+    local bindir=$Bindir/$arch
+    local bin=sigtool
+
+    if [ "$os" = "windows" ]; then
+        bin=${bin}.exe
+    fi
+
+    ./build -V $rev -b $Bindir -s -a $arch || die "can't build $arch"
+    (cd $bindir && tar cf - $bin)  | gzip -9 > $tgz || die "can't tar $tgz"
+}
+
+xrev=$(git describe --always --dirty --abbrev=12) || exit 1
+if echo $xrev | grep -q dirty; then
+    die "won't build releases; repo dirty!"
+    true
+fi
+
+os="linux windows openbsd darwin"
+arch="amd64 arm64"
+
+for xx in $os; do
+    for yy in $arch; do
+        pkgit $xx $yy $xrev
+    done
+done

renovate.json

@@ -0,0 +1,3 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json"
+}

sign/README.md

@@ -1,10 +1,10 @@
-[![GoDoc](https://godoc.org/github.com/opencoff/sigtool/sign?status.svg)](https://godoc.org/github.com/opencoff/sigtool/sign)
+[![GoDoc](https://godoc.org/git.rgst.io/homelab/sigtool/v3/sign?status.svg)](https://godoc.org/git.rgst.io/homelab/sigtool/v3/sign)
 
 # sigtool/sign - Ed25519 signature calculation and verification
 
 This is a small library that makes it easier to create and serialize Ed25519 keys, and sign,
 verify files using those keys. The library uses mmap(2) to read and process very large files.
 
-The companion program [sigtool](https://github.com/opencoff/sigtool) uses this library.
+The companion program [sigtool](https://git.rgst.io/homelab/sigtool/v3) uses this library.
 ## License
 GPL v2.0

sign/encrypt.go

@@ -26,29 +26,36 @@
 //
 // Variable Length Segment:
 //    - Protobuf encoded, per-recipient wrapped keys
-//    - Shasum:  32 bytes (SHA256 of full header)
 //
 // The variable length segment consists of one or more
-// recipients, each with their wrapped keys. This is encoded as
+// recipients, each with their individually wrapped keys.
-// a protobuf message. This protobuf encoded message immediately
-// follows the fixed length header.
 //
 // The input data is encrypted with an expanded random 32-byte key:
-//    - Prefix_string = "Encrypt Nonce"
+//    - hkdf-sha512 of random key, salt, context
-//    - datakey = SHA256(Prefix_string || header_checksum || random_key)
+//    - the hkdf process yields a data-encryption key, nonce and hmac key.
-//    - The header checksum is mixed in the above process to ensure we
+//    - we use the header checksum as the 'salt' for HKDF; this ensures that
-//      catch any malicious modification of the header.
+//      any modification of the header yields different keys
+//
+// We also calculate the cumulative hmac-sha256 of the plaintext blocks.
+//    - When sender identity is present, we sign the final hmac and append
+//	the signature as the "trailer".
+//    - When sender identity is NOT present, we put random bytes as the
+//      "signature". ie in either case, there is a trailer.
+//
+// Note: If the trailer is missing from a sigtool encrypted file - the
+// recipient has no guarantees of content immutability (ie tampering
+// from one of the _other_ recipients).
 //
 // The input data is broken up into "chunks"; each no larger than
 // maxChunkSize. The default block size is "chunkSize". Each block
 // is AEAD encrypted:
-//   AEAD nonce = header.salt || block# || block-size
+//   AEAD nonce = header.nonce || block#
+//   AD of AEAD = chunk length+eof marker
 //
 // The encrypted block (includes the AEAD tag) length is written
 // as a big-endian 4-byte prefix. The high-order bit of this length
 // field is set for the last-block (denoting EOF).
 //
-// The encrypted blocks use an opinionated nonce length of 32 (_AEADNonceLen).
 
 package sign
 
@@ -57,50 +64,65 @@ import (
 	"crypto/aes"
 	"crypto/cipher"
 	"crypto/ed25519"
+	"crypto/hmac"
 	"crypto/sha256"
 	"crypto/sha512"
 	"crypto/subtle"
 	"encoding/binary"
 	"fmt"
+	"hash"
+	"io"
+	"os"
+
 	"golang.org/x/crypto/curve25519"
 	"golang.org/x/crypto/hkdf"
-	"io"
 
-	"github.com/opencoff/sigtool/internal/pb"
+	"git.rgst.io/homelab/sigtool/v3/internal/pb"
 )
 
 // Encryption chunk size = 4MB
 const (
-	chunkSize    uint32 = 4 * 1048576
+	// The latest version of the tool's output file format
+	_SigtoolVersion = 3
+
+	chunkSize    uint32 = 4 * 1048576 // 4 MB
 	maxChunkSize uint32 = 1 << 30
 	_EOF         uint32 = 1 << 31
 
-	_Magic          = "SigTool"
+	_Magic       = "SigTool"
-	_MagicLen       = len(_Magic)
+	_MagicLen    = len(_Magic)
-	_SigtoolVersion = 2
+	_FixedHdrLen = _MagicLen + 1 + 4 // 1: version, 4: len of variable segment
-	_AEADNonceLen   = 32
-	_FixedHdrLen    = _MagicLen + 1 + 4
 
-	_WrapReceiverNonce = "Receiver Key Nonce"
+	_AesKeySize    = 32
-	_WrapSenderNonce   = "Sender Sig Nonce"
+	_AEADNonceSize = 12
-	_EncryptNonce      = "Encrypt Nonce"
+	_SaltSize      = 32
+	_RxNonceSize   = 12 // nonce size of per-recipient encrypted blocks
+
+	_WrapReceiver     = "Receiver Key"
+	_WrapSender       = "Sender Sig"
+	_DataKeyExpansion = "Data Key Expansion"
 )
 
 // Encryptor holds the encryption context
 type Encryptor struct {
 	pb.Header
-	key []byte // file encryption key
+	key []byte // root key
 
-	ae cipher.AEAD
+	nonce []byte // nonce for the data encrypting cipher
+	buf   []byte // I/O buf (chunk-sized)
+
+	ae   cipher.AEAD
+	hmac hash.Hash
 
 	// ephemeral key
 	encSK []byte
 
-	started bool
+	// sender identity
+	sender *PrivateKey
 
-	hdrsum []byte
+	auth    bool // set if the sender idetity is sent
-	buf    []byte
+	started bool
-	stream bool
+	stream  bool
 }
 
 // Create a new Encryption context for encrypting blocks of size 'blksize'.
@@ -123,42 +145,23 @@ func NewEncryptor(sk *PrivateKey, blksize uint64) (*Encryptor, error) {
 		return nil, fmt.Errorf("encrypt: %w", err)
 	}
 
-	key := make([]byte, 32)
+	key := randBuf(_AesKeySize)
-	salt := make([]byte, _AEADNonceLen)
+	salt := randBuf(_SaltSize)
-
-	randRead(key)
-	randRead(salt)
-
-	// if sender has provided their identity to authenticate, we sign the data-enc key
-	// and encrypt the signature. At no point will we send the sender's identity.
-	var senderSig []byte
-	if sk != nil {
-		sig, err := sk.SignMessage(key, "")
-		if err != nil {
-			return nil, fmt.Errorf("encrypt: can't sign: %w", err)
-		}
-
-		senderSig = sig.Sig
-	} else {
-		var zero [ed25519.SignatureSize]byte
-		senderSig = zero[:]
-	}
-
-	wSig, err := wrapSenderSig(senderSig, key, salt)
-	if err != nil {
-		return nil, fmt.Errorf("encrypt: %w", err)
-	}
 
 	e := &Encryptor{
 		Header: pb.Header{
-			ChunkSize:  blksz,
+			ChunkSize: blksz,
-			Salt:       salt,
+			Salt:      salt,
-			Pk:         epk,
+			Pk:        epk,
-			SenderSign: wSig,
 		},
 
-		key:   key,
+		key:    key,
-		encSK: esk,
+		encSK:  esk,
+		sender: sk,
+	}
+
+	if err = e.addSenderSig(sk); err != nil {
+		return nil, fmt.Errorf("encrypt: %w", err)
 	}
 
 	return e, nil
@@ -225,8 +228,8 @@ func (e *Encryptor) start(wr io.Writer) error {
 
 	buffer := make([]byte, _FixedHdrLen+varSize+sha256.Size)
 	fixHdr := buffer[:_FixedHdrLen]
-	varHdr := buffer[_FixedHdrLen:]
+	varHdr := buffer[_FixedHdrLen : _FixedHdrLen+varSize]
-	sumHdr := varHdr[varSize:]
+	sumHdr := buffer[_FixedHdrLen+varSize:]
 
 	// Now assemble the fixed header
 	copy(fixHdr[:], []byte(_Magic))
@@ -239,70 +242,117 @@ func (e *Encryptor) start(wr io.Writer) error {
 		return fmt.Errorf("encrypt: can't marshal header: %w", err)
 	}
 
-	// Now calculate checksum of everything
 	h := sha256.New()
 	h.Write(buffer[:_FixedHdrLen+varSize])
-	h.Sum(sumHdr[:0])
+	cksum := h.Sum(sumHdr[:0])
 
-	// Finally write it out
+	// now make the data encryption keys, nonces etc.
+	outbuf := make([]byte, sha256.Size+_AesKeySize+_AEADNonceSize)
+
+	// we mix the header checksum (and it captures the sigtool version, sender
+	// identity, etc.)
+	buf := expand(outbuf, e.key, cksum, []byte(_DataKeyExpansion))
+
+	var dkey, hmackey []byte
+
+	e.nonce, buf = buf[:_AEADNonceSize], buf[_AEADNonceSize:]
+	dkey, buf = buf[:_AesKeySize], buf[_AesKeySize:]
+	hmackey = buf
+
+	aes, err := aes.NewCipher(dkey)
+	if err != nil {
+		return fmt.Errorf("encrypt: %w", err)
+	}
+
+	if e.ae, err = cipher.NewGCM(aes); err != nil {
+		return fmt.Errorf("encrypt: %w", err)
+	}
+
+	// Finally write out the header
 	err = fullwrite(buffer, wr)
 	if err != nil {
 		return fmt.Errorf("encrypt: %w", err)
 	}
 
-	// we mix the header checksum to create the encryption key
+	e.hmac = hmac.New(sha256.New, hmackey)
-	h = sha256.New()
+	e.buf = make([]byte, e.ChunkSize+4+uint32(e.ae.Overhead()))
-	h.Write([]byte(_EncryptNonce))
-	h.Write(e.key)
-	h.Write(sumHdr)
-	key := h.Sum(nil)
-
-	aes, err := aes.NewCipher(key)
-	if err != nil {
-		return fmt.Errorf("encrypt: %w", err)
-	}
-
-	ae, err := cipher.NewGCMWithNonceSize(aes, _AEADNonceLen)
-	if err != nil {
-		return fmt.Errorf("encrypt: %w", err)
-	}
-
-	e.buf = make([]byte, e.ChunkSize+4+uint32(ae.Overhead()))
-	e.ae = ae
-
 	e.started = true
+
+	debug("encrypt:\n\thdr-cksum: %x\n\taes-key: %x\n\tnonce: %x\n\thmac-key: %x\n",
+		cksum, dkey, e.nonce, hmackey)
+
 	return nil
 }
 
 // encrypt exactly _one_ block of data
-// The nonce for the block is: sha256(salt || chunkLen || block#)
+// The nonce is constructed from the salt, block# and block-size.
 // This protects the output stream from re-ordering attacks and length
 // modification attacks. The encoded length & block number is used as
 // additional data in the AEAD construction.
-func (e *Encryptor) encrypt(buf []byte, wr io.Writer, i uint32, eof bool) error {
+func (e *Encryptor) encrypt(pt []byte, wr io.Writer, i uint32, eof bool) error {
-	var z uint32 = uint32(len(buf))
+	var z uint32 = uint32(len(pt))
-	var nbuf [_AEADNonceLen]byte
+	var nonce [_AEADNonceSize]byte
 
 	// mark last block
 	if eof {
 		z |= _EOF
 	}
 
-	b := e.buf[:8]
+	copy(nonce[:], e.nonce)
-	binary.BigEndian.PutUint32(b[:4], z)
-	binary.BigEndian.PutUint32(b[4:], i)
 
-	nonce := makeNonceV2(nbuf[:], e.Salt, b)
+	// now change the upper bytes to track the block#; we use the len+eof as AD
+	binary.BigEndian.PutUint32(nonce[:4], i)
 
-	cbuf := e.buf[4:]
+	// put the encoded length+eof at the start of the output buf
-	c := e.ae.Seal(cbuf[:0], nonce, buf, b[:])
+	b := e.buf[:4]
+	ctbuf := e.buf[4:]
+
+	binary.BigEndian.PutUint32(b, z)
+	ct := e.ae.Seal(ctbuf[:0], nonce[:], pt, b)
 
 	// total number of bytes written
-	n := len(c) + 4
+	n := len(ct) + 4
 	err := fullwrite(e.buf[:n], wr)
 	if err != nil {
 		return fmt.Errorf("encrypt: %w", err)
 	}
+
+	e.hmac.Write(b)
+	e.hmac.Write(pt)
+
+	if eof {
+		return e.writeTrailer(wr)
+	}
+	return nil
+}
+
+// Write a trailer:
+//   - if authenticating sender, sign the hmac and put the signature in the trailer
+//   - if not authenticating sender, write random bytes to the trailer
+func (e *Encryptor) writeTrailer(wr io.Writer) error {
+	var tr []byte
+
+	switch e.auth {
+	case true:
+		var hmac [sha256.Size]byte
+
+		e.hmac.Sum(hmac[:0])
+
+		// We know sender is non null.
+		sig, err := e.sender.SignMessage(hmac[:], "")
+		if err != nil {
+			return fmt.Errorf("encrypt: trailer: %w", err)
+		}
+		tr = sig.Sig
+
+	case false:
+		tr = randBuf(ed25519.SignatureSize)
+
+	}
+
+	if err := fullwrite(tr, wr); err != nil {
+		return fmt.Errorf("encrypt: trailer %w", err)
+	}
 	return nil
 }
 
@@ -310,16 +360,18 @@ func (e *Encryptor) encrypt(buf []byte, wr io.Writer, i uint32, eof bool) error
 type Decryptor struct {
 	pb.Header
 
-	ae     cipher.AEAD
+	ae   cipher.AEAD
-	rd     io.Reader
+	hmac hash.Hash
-	buf    []byte
-	hdrsum []byte
 
-	// flag set to true if sender signed the key
+	sender *PublicKey
-	auth bool
 
-	// Decrypted key
+	rd    io.Reader
-	key    []byte
+	buf   []byte
+	nonce []byte // nonce for the data decrypting cipher
+
+	key    []byte // Decrypted root key
+	hdrsum []byte // cached header checksum
+	auth   bool   // flag set to true if sender signed the key
 	eof    bool
 	stream bool
 }
@@ -362,14 +414,18 @@ func NewDecryptor(rd io.Reader) (*Decryptor, error) {
 		return nil, fmt.Errorf("decrypt: error while reading header: %w", err)
 	}
 
+	// The checksum in the header
 	verify := varBuf[varSize:]
 
+	// the checksum we calculated
+	var csum [sha256.Size]byte
+
 	h := sha256.New()
 	h.Write(b[:])
 	h.Write(varBuf[:varSize])
-	cksum := h.Sum(nil)
+	cksum := h.Sum(csum[:0])
 
-	if subtle.ConstantTimeCompare(verify, cksum[:]) == 0 {
+	if subtle.ConstantTimeCompare(verify, cksum) == 0 {
 		return nil, ErrBadHeader
 	}
 
@@ -387,7 +443,7 @@ func NewDecryptor(rd io.Reader) (*Decryptor, error) {
 		return nil, fmt.Errorf("decrypt: invalid chunkSize %d", d.ChunkSize)
 	}
 
-	if len(d.Salt) != _AEADNonceLen {
+	if len(d.Salt) != _SaltSize {
 		return nil, fmt.Errorf("decrypt: invalid nonce length %d", len(d.Salt))
 	}
 
@@ -397,7 +453,7 @@ func NewDecryptor(rd io.Reader) (*Decryptor, error) {
 
 	// sanity check on the wrapped keys
 	for i, w := range d.Keys {
-		if len(w.DKey) <= 32 {
+		if len(w.DKey) <= _AesKeySize {
 			return nil, fmt.Errorf("decrypt: wrapped key %d: wrong-size encrypted key", i)
 		}
 	}
@@ -417,6 +473,8 @@ func (d *Decryptor) SetPrivateKey(sk *PrivateKey, senderPk *PublicKey) error {
 			return fmt.Errorf("decrypt: can't unwrap key %d: %w", i, err)
 		}
 		if key != nil {
+			d.key = key
+			d.sender = senderPk
 			goto havekey
 		}
 	}
@@ -424,28 +482,37 @@ func (d *Decryptor) SetPrivateKey(sk *PrivateKey, senderPk *PublicKey) error {
 	return ErrBadKey
 
 havekey:
-	if err := d.verifySender(key, sk, senderPk); err != nil {
+	if err := d.verifySender(key, senderPk); err != nil {
 		return fmt.Errorf("decrypt: %w", err)
 	}
 
-	d.key = key
+	outbuf := make([]byte, sha256.Size+_AesKeySize+_AEADNonceSize)
 
-	// we mix the header checksum into the key
+	buf := expand(outbuf, d.key, d.hdrsum, []byte(_DataKeyExpansion))
-	h := sha256.New()
-	h.Write([]byte(_EncryptNonce))
-	h.Write(d.key)
-	h.Write(d.hdrsum)
-	key = h.Sum(nil)
 
-	aes, err := aes.NewCipher(key)
+	var dkey, hmackey []byte
+
+	d.nonce, buf = buf[:_AEADNonceSize], buf[_AEADNonceSize:]
+	dkey, buf = buf[:_AesKeySize], buf[_AesKeySize:]
+	hmackey = buf
+
+	d.hmac = hmac.New(sha256.New, hmackey)
+
+	aes, err := aes.NewCipher(dkey)
 	if err != nil {
 		return fmt.Errorf("decrypt: %w", err)
 	}
 
-	d.ae, err = cipher.NewGCMWithNonceSize(aes, _AEADNonceLen)
+	d.ae, err = cipher.NewGCM(aes)
 	if err != nil {
 		return fmt.Errorf("decrypt: %w", err)
 	}
+
+	debug("decrypt:\n\thdr-cksum: %x\n\taes-key: %x\n\tnonce: %x\n\thmac-key: %x\n",
+		d.hdrsum, dkey, d.nonce, hmackey)
+
+	// We have a separate on-stack buffer for reading the header (4 bytes).
+	// Thus, the actual I/O buf will never be larger than the chunksize + AEAD Overhead
 	d.buf = make([]byte, int(d.ChunkSize)+d.ae.Overhead())
 	return nil
 }
@@ -488,24 +555,21 @@ func (d *Decryptor) Decrypt(wr io.Writer) error {
 			return nil
 		}
 	}
-	return nil
 }
 
 // Decrypt exactly one chunk of data
 func (d *Decryptor) decrypt(i uint32) ([]byte, bool, error) {
-	var b [8]byte
-	var nonceb [32]byte
 	var ovh uint32 = uint32(d.ae.Overhead())
-	var p []byte
+	var b [4]byte
+	var nonce [_AEADNonceSize]byte
 
-	n, err := io.ReadFull(d.rd, b[:4])
+	n, err := io.ReadFull(d.rd, b[:])
 	if err != nil || n == 0 {
 		return nil, false, fmt.Errorf("decrypt: premature EOF while reading header block %d", i)
 	}
 
-	m := binary.BigEndian.Uint32(b[:4])
+	m := binary.BigEndian.Uint32(b[:])
 	eof := (m & _EOF) > 0
-
 	m &= (_EOF - 1)
 
 	// Sanity check - in case of corrupt header
@@ -517,16 +581,14 @@ func (d *Decryptor) decrypt(i uint32) ([]byte, bool, error) {
 		if !eof {
 			return nil, false, fmt.Errorf("decrypt: block %d: zero-sized chunk without EOF", i)
 		}
-		return p, eof, nil
+		return nil, eof, nil
-
-	case m < ovh:
-		return nil, false, fmt.Errorf("decrypt: chunksize is too small (%d)", m)
 
 	default:
 	}
 
-	binary.BigEndian.PutUint32(b[4:], i)
+	// make the nonce - top 4 bytes are the counter
-	nonce := makeNonceV2(nonceb[:], d.Salt, b[:])
+	copy(nonce[:], d.nonce)
+	binary.BigEndian.PutUint32(nonce[:4], i)
 
 	z := m + ovh
 	n, err = io.ReadFull(d.rd, d.buf[:z])
@@ -534,39 +596,115 @@ func (d *Decryptor) decrypt(i uint32) ([]byte, bool, error) {
 		return nil, false, fmt.Errorf("decrypt: premature EOF while reading block %d: %w", i, err)
 	}
 
-	p, err = d.ae.Open(d.buf[:0], nonce, d.buf[:n], b[:])
+	pt, err := d.ae.Open(d.buf[:0], nonce[:], d.buf[:n], b[:])
 	if err != nil {
 		return nil, false, fmt.Errorf("decrypt: can't decrypt chunk %d: %w", i, err)
 	}
 
-	return p[:m], eof, nil
+	if uint32(len(pt)) != m {
+		return nil, false, fmt.Errorf("decrypt: partial unsealed bytes; exp %d, saw %d", m, len(pt))
+	}
+
+	d.hmac.Write(b[:])
+	d.hmac.Write(pt)
+
+	if eof {
+		return d.processTrailer(pt, eof)
+	}
+
+	return pt, eof, nil
 }
 
-// Wrap sender's signature of the encryption key
+func (d *Decryptor) processTrailer(pt []byte, eof bool) ([]byte, bool, error) {
-func wrapSenderSig(sig []byte, key, salt []byte) ([]byte, error) {
+	var rd [ed25519.SignatureSize]byte
-	aes, err := aes.NewCipher(key)
+
+	_, err := io.ReadFull(d.rd, rd[:])
 	if err != nil {
-		return nil, fmt.Errorf("wrap: %w", err)
+		return nil, false, fmt.Errorf("decrypt: premature EOF while reading trailer: %w", err)
+	}
+
+	if !d.auth {
+		// these are random bytes; ignore em
+		return pt, eof, nil
+	}
+
+	var hmac [sha256.Size]byte
+
+	cksum := d.hmac.Sum(hmac[:0])
+	ss := &Signature{
+		Sig: rd[:],
+	}
+
+	if ok := d.sender.VerifyMessage(cksum, ss); !ok {
+		return nil, eof, ErrBadTrailer
+	}
+
+	return pt, eof, nil
+}
+
+// optionally sign the checksum and encrypt everything
+func (e *Encryptor) addSenderSig(sk *PrivateKey) error {
+	var zero [ed25519.SignatureSize]byte
+	var auth bool
+	sig := zero[:]
+
+	if e.sender != nil {
+		var csum [sha256.Size]byte
+
+		// We capture essential meta-data from the sender; viz:
+		//  - Sender tool version
+		//  - Sender generated curve25519 PK
+		//  - session salt, root key
+
+		h := sha256.New()
+		h.Write([]byte(_Magic))
+		h.Write([]byte{_SigtoolVersion})
+		h.Write(e.Pk)
+		h.Write(e.Salt)
+		h.Write(e.key)
+		cksum := h.Sum(csum[:0])
+
+		xsig, err := e.sender.SignMessage(cksum, "")
+		if err != nil {
+			return fmt.Errorf("wrap: can't sign: %w", err)
+		}
+		sig = xsig.Sig
+		auth = true
+	}
+
+	buf := make([]byte, _AesKeySize+_AEADNonceSize)
+	buf = expand(buf, e.key, e.Salt, []byte(_WrapSender))
+
+	ekey, nonce := buf[:_AesKeySize], buf[_AesKeySize:]
+
+	aes, err := aes.NewCipher(ekey)
+	if err != nil {
+		return fmt.Errorf("senderId: %w", err)
 	}
 
 	ae, err := cipher.NewGCM(aes)
 	if err != nil {
-		return nil, fmt.Errorf("wrap: %w", err)
+		return fmt.Errorf("senderId: %w", err)
 	}
 
-	tagsize := ae.Overhead()
+	outbuf := make([]byte, ed25519.SignatureSize+ae.Overhead())
-	nonceSize := ae.NonceSize()
+	buf = ae.Seal(outbuf[:0], nonce, sig, nil)
 
-	nonce := sha256Slices([]byte(_WrapSenderNonce), salt)[:nonceSize]
+	e.auth = auth
-	esig := make([]byte, tagsize+len(sig))
+	e.Sender = buf
 
-	return ae.Seal(esig[:0], nonce, sig, nil), nil
+	return nil
 }
 
 // unwrap sender's signature using 'key' and extract the signature
 // Optionally, verify the signature using the sender's PK (if provided).
-func (d *Decryptor) verifySender(key []byte, sk *PrivateKey, senderPK *PublicKey) error {
+func (d *Decryptor) verifySender(key []byte, senderPk *PublicKey) error {
-	aes, err := aes.NewCipher(key)
+	outbuf := make([]byte, _AEADNonceSize+_AesKeySize)
+	buf := expand(outbuf, key, d.Salt, []byte(_WrapSender))
+
+	ekey, nonce := buf[:_AesKeySize], buf[_AesKeySize:]
+
+	aes, err := aes.NewCipher(ekey)
 	if err != nil {
 		return fmt.Errorf("unwrap: %w", err)
 	}
@@ -576,46 +714,70 @@ func (d *Decryptor) verifySender(key []byte, sk *PrivateKey, senderPK *PublicKey
 		return fmt.Errorf("unwrap: %w", err)
 	}
 
-	nonceSize := ae.NonceSize()
+	var sigbuf [ed25519.SignatureSize]byte
-	nonce := sha256Slices([]byte(_WrapSenderNonce), d.Salt)[:nonceSize]
+	var zero [ed25519.SignatureSize]byte
-	sig := make([]byte, ed25519.SignatureSize)
+
-	sig, err = ae.Open(sig[:0], nonce, d.SenderSign, nil)
+	sig, err := ae.Open(sigbuf[:0], nonce, d.Sender, nil)
 	if err != nil {
 		return fmt.Errorf("unwrap: can't open sender info: %w", err)
 	}
 
-	var zero [ed25519.SignatureSize]byte
-
 	// Did the sender actually sign anything?
 	if subtle.ConstantTimeCompare(zero[:], sig) == 0 {
-		d.auth = true
+		if senderPk == nil {
-
+			return ErrNoSenderPK
-		if senderPK != nil {
-			ss := &Signature{
-				Sig: sig,
-			}
-
-			ok := senderPK.VerifyMessage(key, ss)
-			if !ok {
-				return fmt.Errorf("unwrap: sender verification failed")
-			}
 		}
+
+		var csum [sha256.Size]byte
+
+		h := sha256.New()
+		h.Write([]byte(_Magic))
+		h.Write([]byte{_SigtoolVersion})
+		h.Write(d.Pk)
+		h.Write(d.Salt)
+		h.Write(key)
+		cksum := h.Sum(csum[:0])
+
+		ss := &Signature{
+			Sig: sig,
+		}
+
+		if ok := senderPk.VerifyMessage(cksum, ss); !ok {
+			return ErrBadSender
+		}
+
+		// we set this to indicate that the sender authenticated themselves;
+		d.auth = true
 	}
+
 	return nil
 }
 
 // Wrap data encryption key 'k' with the sender's PK and our ephemeral curve SK
-//  basically, we do two scalarmults:
+//
-//    a) Ephemeral encryption/decryption SK x receiver PK
+//	basically, we do a scalarmult: Ephemeral encryption/decryption SK x receiver PK
-//    b) Sender's  SK x receiver PK
 func (e *Encryptor) wrapKey(pk *PublicKey) (*pb.WrappedKey, error) {
-	rxPK := pk.toCurve25519PK()
+	rxPK := pk.ToCurve25519PK()
-	dkek, err := curve25519.X25519(e.encSK, rxPK)
+	sekrit, err := curve25519.X25519(e.encSK, rxPK)
 	if err != nil {
 		return nil, fmt.Errorf("wrap: %w", err)
 	}
 
-	aes, err := aes.NewCipher(dkek)
+	var shasum [sha256.Size]byte
+
+	rbuf := randBuf(_RxNonceSize)
+
+	h := sha256.New()
+	h.Write(e.Salt)
+	h.Write(rbuf[:])
+	h.Sum(shasum[:0])
+
+	out := make([]byte, _AesKeySize+_RxNonceSize)
+	buf := expand(out[:], sekrit, shasum[:], []byte(_WrapReceiver))
+
+	kek, nonce := buf[:_AesKeySize], buf[_AesKeySize:]
+
+	aes, err := aes.NewCipher(kek)
 	if err != nil {
 		return nil, fmt.Errorf("wrap: %w", err)
 	}
@@ -625,14 +787,10 @@ func (e *Encryptor) wrapKey(pk *PublicKey) (*pb.WrappedKey, error) {
 		return nil, fmt.Errorf("wrap: %w", err)
 	}
 
-	tagsize := ae.Overhead()
+	ekey := make([]byte, ae.Overhead()+len(e.key))
-	nonceSize := ae.NonceSize()
-
-	nonceR := sha256Slices([]byte(_WrapReceiverNonce), e.Salt)[:nonceSize]
-	ekey := make([]byte, tagsize+len(e.key))
-
 	w := &pb.WrappedKey{
-		DKey: ae.Seal(ekey[:0], nonceR, e.key, pk.Pk),
+		DKey:  ae.Seal(ekey[:0], nonce, e.key, pk.Pk),
+		Nonce: rbuf,
 	}
 
 	return w, nil
@@ -641,41 +799,49 @@ func (e *Encryptor) wrapKey(pk *PublicKey) (*pb.WrappedKey, error) {
 // Unwrap a wrapped key using the receivers Ed25519 secret key 'sk' and
 // senders ephemeral PublicKey
 func (d *Decryptor) unwrapKey(w *pb.WrappedKey, sk *PrivateKey) ([]byte, error) {
-	ourSK := sk.toCurve25519SK()
+	ourSK := sk.ToCurve25519SK()
-	dkek, err := curve25519.X25519(ourSK, d.Pk)
+	sekrit, err := curve25519.X25519(ourSK, d.Pk)
 	if err != nil {
 		return nil, fmt.Errorf("unwrap: %w", err)
 	}
 
-	aes, err := aes.NewCipher(dkek)
+	var shasum [sha256.Size]byte
+
+	h := sha256.New()
+	h.Write(d.Salt)
+	h.Write(w.Nonce)
+	h.Sum(shasum[:0])
+
+	out := make([]byte, _AesKeySize+_RxNonceSize)
+	buf := expand(out[:], sekrit, shasum[:], []byte(_WrapReceiver))
+
+	kek, nonce := buf[:_AesKeySize], buf[_AesKeySize:]
+
+	aes, err := aes.NewCipher(kek)
 	if err != nil {
-		return nil, fmt.Errorf("unwrap: %w", err)
+		return nil, fmt.Errorf("wrap: %w", err)
 	}
 
 	ae, err := cipher.NewGCM(aes)
 	if err != nil {
-		return nil, fmt.Errorf("unwrap: %w", err)
+		return nil, fmt.Errorf("wrap: %w", err)
 	}
 
-	// 32 == AES-256 key size
+	want := _AesKeySize + ae.Overhead()
-	want := 32 + ae.Overhead()
 	if len(w.DKey) != want {
 		return nil, fmt.Errorf("unwrap: incorrect decrypt bytes (need %d, saw %d)", want, len(w.DKey))
 	}
 
-	nonceSize := ae.NonceSize()
-
-	nonceR := sha256Slices([]byte(_WrapReceiverNonce), d.Salt)[:nonceSize]
 	pk := sk.PublicKey()
-
+	dkey := make([]byte, _AesKeySize) // decrypted data decryption key
-	dkey := make([]byte, 32) // decrypted data decryption key
 
 	// we indicate incorrect receiver SK by returning a nil key
-	dkey, err = ae.Open(dkey[:0], nonceR, w.DKey, pk.Pk)
+	dkey, err = ae.Open(dkey[:0], nonce, w.DKey, pk.Pk)
 	if err != nil {
 		return nil, nil
 	}
 
+	// we have successfully found the correct recipient
 	return dkey, nil
 }
 
@@ -695,30 +861,14 @@ func fullwrite(buf []byte, wr io.Writer) error {
 	return nil
 }
 
-// make aead nonce from salt, chunk-size and block#
-// First 8 bytes are chunk-size and nonce (in 'ad')
-func makeNonceV2(dest []byte, salt []byte, ad []byte) []byte {
-	n := len(ad)
-	copy(dest, ad)
-	copy(dest[n:], salt)
-	return dest
-}
-
-// make aead nonce from salt, chunk-size and block# for v1
-// This is here for historical documentation purposes
-func makeNonceV1(dest []byte, salt []byte, ad []byte) []byte {
-	h := sha256.New()
-	h.Write(salt)
-	h.Write(ad)
-	return h.Sum(dest[:0])
-}
-
 // generate a KEK from a shared DH key and a Pub Key
-func expand(shared, pk []byte) ([]byte, error) {
+func expand(out []byte, shared, salt, ad []byte) []byte {
-	kek := make([]byte, 32)
+	h := hkdf.New(sha512.New, shared, salt, ad)
-	h := hkdf.New(sha512.New, shared, pk, nil)
+	_, err := io.ReadFull(h, out)
-	_, err := io.ReadFull(h, kek)
+	if err != nil {
-	return kek, err
+		panic(fmt.Sprintf("hkdf: failed to generate %d bytes: %s", len(out), err))
+	}
+	return out
 }
 
 func newSender() (sk, pk []byte, err error) {
@@ -740,4 +890,25 @@ func sha256Slices(v ...[]byte) []byte {
 	return h.Sum(nil)[:]
 }
 
+var _debug int = 0
+
+// Enable debugging of this module;
+// level > 0 elicits debug messages on os.Stderr
+func Debug(level int) {
+	_debug = level
+}
+
+func debug(s string, v ...interface{}) {
+	if _debug <= 0 {
+		return
+	}
+
+	z := fmt.Sprintf(s, v...)
+	if n := len(z); z[n-1] != '\n' {
+		z += "\n"
+	}
+	os.Stderr.WriteString(z)
+	os.Stderr.Sync()
+}
+
 // EOF

sign/encrypt_test.go

@@ -34,8 +34,10 @@ func (b *Buffer) Close() error {
 func TestEncryptSimple(t *testing.T) {
 	assert := newAsserter(t)
 
-	receiver, err := NewKeypair()
+	sk, err := NewPrivateKey()
-	assert(err == nil, "receiver keypair gen failed: %s", err)
+	assert(err == nil, "SK gen failed: %s", err)
+
+	pk := sk.PublicKey()
 
 	var blkSize int = 1024
 	var size int = (blkSize * 10)
@@ -49,7 +51,7 @@ func TestEncryptSimple(t *testing.T) {
 	ee, err := NewEncryptor(nil, uint64(blkSize))
 	assert(err == nil, "encryptor create fail: %s", err)
 
-	err = ee.AddRecipient(&receiver.Pub)
+	err = ee.AddRecipient(pk)
 	assert(err == nil, "can't add recipient: %s", err)
 
 	rd := bytes.NewBuffer(buf)
@@ -63,7 +65,7 @@ func TestEncryptSimple(t *testing.T) {
 	dd, err := NewDecryptor(rd)
 	assert(err == nil, "decryptor create fail: %s", err)
 
-	err = dd.SetPrivateKey(&receiver.Sec, nil)
+	err = dd.SetPrivateKey(sk, nil)
 	assert(err == nil, "decryptor can't add SK: %s", err)
 
 	wr = Buffer{}
@@ -76,12 +78,67 @@ func TestEncryptSimple(t *testing.T) {
 	assert(byteEq(b, buf), "decrypt content mismatch")
 }
 
+// one sender, one receiver - small blocks
+func TestEncryptSmallSizes(t *testing.T) {
+	assert := newAsserter(t)
+
+	sk, err := NewPrivateKey()
+	assert(err == nil, "SK gen failed: %s", err)
+
+	pk := sk.PublicKey()
+
+	var blkSize int = 8
+	var size int = (blkSize * 4)
+
+	// cleartext
+	bigbuf := make([]byte, size)
+	for i := 0; i < len(bigbuf); i++ {
+		bigbuf[i] = byte(i & 0xff)
+	}
+
+	// encrypt progressively larger bufs
+	for i := 1; i < len(bigbuf); i++ {
+		buf := bigbuf[:i]
+
+		ee, err := NewEncryptor(nil, uint64(blkSize))
+		assert(err == nil, "encryptor-%d create fail: %s", i, err)
+
+		err = ee.AddRecipient(pk)
+		assert(err == nil, "encryptor-%d: can't add recipient: %s", i, err)
+
+		rd := bytes.NewBuffer(buf)
+		wr := Buffer{}
+
+		err = ee.Encrypt(rd, &wr)
+		assert(err == nil, "encrypt-%d fail: %s", i, err)
+
+		rd = bytes.NewBuffer(wr.Bytes())
+
+		dd, err := NewDecryptor(rd)
+		assert(err == nil, "decryptor-%d create fail: %s", i, err)
+
+		err = dd.SetPrivateKey(sk, nil)
+		assert(err == nil, "decryptor-%d can't add SK: %s", i, err)
+
+		wr = Buffer{}
+		err = dd.Decrypt(&wr)
+		assert(err == nil, "decrypt-%d fail: %s", i, err)
+
+		b := wr.Bytes()
+		assert(len(b) == len(buf), "decrypt-%d length mismatch: exp %d, saw %d", i, len(buf), len(b))
+
+		assert(byteEq(b, buf), "decrypt-%d content mismatch", i)
+	}
+}
+
 // test corrupted header or corrupted input
 func TestEncryptCorrupted(t *testing.T) {
 	assert := newAsserter(t)
 
-	receiver, err := NewKeypair()
+	sk, err := NewPrivateKey()
-	assert(err == nil, "receiver keypair gen failed: %s", err)
+	assert(err == nil, "SK gen failed: %s", err)
+
+	pk := sk.PublicKey()
 
 	var blkSize int = 1024
 	var size int = (blkSize * 23) + randmod(blkSize)
@@ -95,7 +152,7 @@ func TestEncryptCorrupted(t *testing.T) {
 	ee, err := NewEncryptor(nil, uint64(blkSize))
 	assert(err == nil, "encryptor create fail: %s", err)
 
-	err = ee.AddRecipient(&receiver.Pub)
+	err = ee.AddRecipient(pk)
 	assert(err == nil, "can't add recipient: %s", err)
 
 	rd := bytes.NewReader(buf)
@@ -107,6 +164,7 @@ func TestEncryptCorrupted(t *testing.T) {
 	rb := wr.Bytes()
 	n := len(rb)
 
+	// corrupt the input
 	for i := 0; i < n; i++ {
 		j := randint() % n
 		rb[j] = byte(randint() & 0xff)
@@ -122,11 +180,11 @@ func TestEncryptCorrupted(t *testing.T) {
 func TestEncryptSenderVerified(t *testing.T) {
 	assert := newAsserter(t)
 
-	sender, err := NewKeypair()
+	sender, err := NewPrivateKey()
-	assert(err == nil, "sender keypair gen failed: %s", err)
+	assert(err == nil, "sender SK gen failed: %s", err)
 
-	receiver, err := NewKeypair()
+	receiver, err := NewPrivateKey()
-	assert(err == nil, "receiver keypair gen failed: %s", err)
+	assert(err == nil, "receiver SK gen failed: %s", err)
 
 	var blkSize int = 1024
 	var size int = (blkSize * 23) + randmod(blkSize)
@@ -137,10 +195,10 @@ func TestEncryptSenderVerified(t *testing.T) {
 		buf[i] = byte(i & 0xff)
 	}
 
-	ee, err := NewEncryptor(&sender.Sec, uint64(blkSize))
+	ee, err := NewEncryptor(sender, uint64(blkSize))
 	assert(err == nil, "encryptor create fail: %s", err)
 
-	err = ee.AddRecipient(&receiver.Pub)
+	err = ee.AddRecipient(receiver.PublicKey())
 	assert(err == nil, "can't add recipient: %s", err)
 
 	rd := bytes.NewBuffer(buf)
@@ -154,14 +212,15 @@ func TestEncryptSenderVerified(t *testing.T) {
 	dd, err := NewDecryptor(rd)
 	assert(err == nil, "decryptor create fail: %s", err)
 
-	// first send a wrong sender key
+	randkey, err := NewPrivateKey()
-	randkey, err := NewKeypair()
+	assert(err == nil, "rand SK gen failed: %s", err)
-	assert(err == nil, "receiver rand keypair gen failed: %s", err)
 
-	err = dd.SetPrivateKey(&receiver.Sec, &randkey.Pub)
+	// first send a wrong sender PK
+	err = dd.SetPrivateKey(receiver, randkey.PublicKey())
 	assert(err != nil, "decryptor failed to verify sender")
 
-	err = dd.SetPrivateKey(&receiver.Sec, &sender.Pub)
+	// then the correct sender PK
+	err = dd.SetPrivateKey(receiver, sender.PublicKey())
 	assert(err == nil, "decryptor can't add SK: %s", err)
 
 	wr = Buffer{}
@@ -178,8 +237,8 @@ func TestEncryptSenderVerified(t *testing.T) {
 func TestEncryptMultiReceiver(t *testing.T) {
 	assert := newAsserter(t)
 
-	sender, err := NewKeypair()
+	sender, err := NewPrivateKey()
-	assert(err == nil, "sender keypair gen failed: %s", err)
+	assert(err == nil, "sender SK gen failed: %s", err)
 
 	var blkSize int = 1024
 	var size int = (blkSize * 23) + randmod(blkSize)
@@ -190,17 +249,17 @@ func TestEncryptMultiReceiver(t *testing.T) {
 		buf[i] = byte(i & 0xff)
 	}
 
-	ee, err := NewEncryptor(&sender.Sec, uint64(blkSize))
+	ee, err := NewEncryptor(sender, uint64(blkSize))
 	assert(err == nil, "encryptor create fail: %s", err)
 
 	n := 4
-	rx := make([]*Keypair, n)
+	rx := make([]*PrivateKey, n)
 	for i := 0; i < n; i++ {
-		r, err := NewKeypair()
+		r, err := NewPrivateKey()
-		assert(err == nil, "can't make receiver key %d: %s", i, err)
+		assert(err == nil, "can't make receiver SK %d: %s", i, err)
 		rx[i] = r
 
-		err = ee.AddRecipient(&r.Pub)
+		err = ee.AddRecipient(r.PublicKey())
 		assert(err == nil, "can't add recipient %d: %s", i, err)
 	}
 
@@ -217,7 +276,7 @@ func TestEncryptMultiReceiver(t *testing.T) {
 		dd, err := NewDecryptor(rd)
 		assert(err == nil, "decryptor %d create fail: %s", i, err)
 
-		err = dd.SetPrivateKey(&rx[i].Sec, &sender.Pub)
+		err = dd.SetPrivateKey(rx[i], sender.PublicKey())
 		assert(err == nil, "decryptor can't add SK %d: %s", i, err)
 
 		wr = Buffer{}
@@ -235,7 +294,7 @@ func TestEncryptMultiReceiver(t *testing.T) {
 func TestStreamIO(t *testing.T) {
 	assert := newAsserter(t)
 
-	receiver, err := NewKeypair()
+	receiver, err := NewPrivateKey()
 	assert(err == nil, "receiver keypair gen failed: %s", err)
 
 	var blkSize int = 1024
@@ -250,7 +309,7 @@ func TestStreamIO(t *testing.T) {
 	ee, err := NewEncryptor(nil, uint64(blkSize))
 	assert(err == nil, "encryptor create fail: %s", err)
 
-	err = ee.AddRecipient(&receiver.Pub)
+	err = ee.AddRecipient(receiver.PublicKey())
 	assert(err == nil, "can't add recipient: %s", err)
 
 	wr := Buffer{}
@@ -283,7 +342,7 @@ func TestStreamIO(t *testing.T) {
 	dd, err := NewDecryptor(rd)
 	assert(err == nil, "decryptor create fail: %s", err)
 
-	err = dd.SetPrivateKey(&receiver.Sec, nil)
+	err = dd.SetPrivateKey(receiver, nil)
 	assert(err == nil, "decryptor can't add SK: %s", err)
 
 	rio, err := dd.NewStreamReader()
@@ -313,6 +372,93 @@ func TestStreamIO(t *testing.T) {
 
 }
 
+// Test stream write and read with small sizes
+func TestSmallSizeStreamIO(t *testing.T) {
+	assert := newAsserter(t)
+
+	receiver, err := NewPrivateKey()
+	assert(err == nil, "receiver SK gen failed: %s", err)
+
+	var blkSize int = 8
+	var size int = blkSize * 10
+
+	// cleartext
+	bigbuf := make([]byte, size)
+	for i := 0; i < len(bigbuf); i++ {
+		bigbuf[i] = byte(i & 0xff)
+	}
+
+	for i := 1; i < len(bigbuf); i++ {
+		buf := bigbuf[:i]
+		t.Logf("small-size-stream: size %d, chunksize %d\n", i, blkSize)
+
+		ee, err := NewEncryptor(nil, uint64(blkSize))
+		assert(err == nil, "encryptor create fail: %s", err)
+
+		err = ee.AddRecipient(receiver.PublicKey())
+		assert(err == nil, "can't add recipient: %s", err)
+
+		wr := Buffer{}
+		wio, err := ee.NewStreamWriter(&wr)
+		assert(err == nil, "can't start stream writer: %s", err)
+
+		// chunksize for writing to stream
+		csize := blkSize - 1
+		rbuf := buf
+		for len(rbuf) > 0 {
+			m := csize
+			if len(rbuf) < m {
+				m = len(rbuf)
+			}
+
+			n, err := wio.Write(rbuf[:m])
+			assert(err == nil, "stream write failed: %s", err)
+			assert(n == m, "stream write mismatch: exp %d, saw %d", m, n)
+
+			rbuf = rbuf[m:]
+		}
+		err = wio.Close()
+		assert(err == nil, "stream close failed: %s", err)
+
+		_, err = wio.Write(buf[:csize])
+		assert(err != nil, "stream write accepted I/O after close: %s", err)
+
+		rd := bytes.NewBuffer(wr.Bytes())
+
+		dd, err := NewDecryptor(rd)
+		assert(err == nil, "decryptor create fail: %s", err)
+
+		err = dd.SetPrivateKey(receiver, nil)
+		assert(err == nil, "decryptor can't add SK: %s", err)
+
+		rio, err := dd.NewStreamReader()
+		assert(err == nil, "stream reader failed: %s", err)
+
+		rbuf = make([]byte, csize)
+		wr = Buffer{}
+		n := 0
+		for {
+			m, err := rio.Read(rbuf)
+			assert(err == nil || err == io.EOF, "streamread fail: %s", err)
+
+			if m > 0 {
+				wr.Write(rbuf[:m])
+				n += m
+			}
+			if err == io.EOF || m == 0 {
+				break
+			}
+		}
+
+		b := wr.Bytes()
+		assert(n == len(b), "streamread: bad buflen; exp %d, saw %d", n, len(b))
+		assert(n == len(buf), "streamread: decrypt len mismatch; exp %d, saw %d", len(buf), n)
+
+		assert(byteEq(b, buf), "decrypt content mismatch")
+	}
+
+}
+
 func randint() int {
 	var b [4]byte
 

sign/errors.go

@@ -20,17 +20,19 @@ import (
 
 var (
 	ErrClosed         = errors.New("encrypt: stream already closed")
-	ErrNoKey          = errors.New("decrypt: No private key set for decryption")
+	ErrNoKey          = errors.New("decrypt: no private key set for decryption")
 	ErrEncStarted     = errors.New("encrypt: can't add new recipient after encryption has started")
 	ErrDecStarted     = errors.New("decrypt: can't add new recipient after decryption has started")
 	ErrEncIsStream    = errors.New("encrypt: can't use Encrypt() after using streaming I/O")
-	ErrNotSigTool     = errors.New("decrypt: Not a sigtool encrypted file?")
+	ErrNotSigTool     = errors.New("decrypt: not a sigtool encrypted file?")
 	ErrHeaderTooBig   = errors.New("decrypt: header too large (max 1048576)")
 	ErrHeaderTooSmall = errors.New("decrypt: header too small (min 32)")
 	ErrBadHeader      = errors.New("decrypt: header corrupted")
-	ErrNoWrappedKeys  = errors.New("decrypt: No wrapped keys in encrypted file")
+	ErrNoWrappedKeys  = errors.New("decrypt: no wrapped keys in encrypted file")
 	ErrBadKey         = errors.New("decrypt: wrong key")
+	ErrBadTrailer     = errors.New("decrypt: message integrity failed (bad trailer)")
 	ErrBadSender      = errors.New("unwrap: sender verification failed")
+	ErrNoSenderPK     = errors.New("unwrap: missing sender public key")
 
 	ErrIncorrectPassword = errors.New("ssh: invalid passphrase")
 	ErrNoPEMFound        = errors.New("ssh: no PEM block found")

sign/iomisc.go

@@ -0,0 +1,67 @@
+// iomisc.go -- misc i/o functions
+//
+// (c) 2016 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package sign
+
+import (
+	"encoding/binary"
+	"fmt"
+	"github.com/opencoff/go-fio"
+	"github.com/opencoff/go-mmap"
+	"hash"
+	"os"
+)
+
+// Simple function to reliably write data to a file.
+// Does MORE than ioutil.WriteFile() - in that it doesn't trash the
+// existing file with an incomplete write.
+func writeFile(fn string, b []byte, ovwrite bool, mode uint32) error {
+	var opts uint32
+	if ovwrite {
+		opts |= fio.OPT_OVERWRITE
+	}
+	sf, err := fio.NewSafeFile(fn, opts, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, os.FileMode(mode))
+	if err != nil {
+		return err
+	}
+	defer sf.Abort()
+	if _, err = sf.Write(b); err != nil {
+		return err
+	}
+
+	return sf.Close()
+}
+
+// Generate file checksum out of hash function h
+func fileCksum(fn string, h hash.Hash) ([]byte, error) {
+	fd, err := os.Open(fn)
+	if err != nil {
+		return nil, fmt.Errorf("can't open %s: %s", fn, err)
+	}
+
+	defer fd.Close()
+
+	sz, err := mmap.Reader(fd, func(b []byte) error {
+		h.Write(b)
+		return nil
+	})
+	if err != nil {
+		return nil, err
+	}
+
+	var b [8]byte
+	binary.BigEndian.PutUint64(b[:], uint64(sz))
+	h.Write(b[:])
+
+	return h.Sum(nil)[:], nil
+}

sign/keys.go

@@ -25,19 +25,14 @@ import (
 	"crypto/sha256"
 	"crypto/sha512"
 	"encoding/base64"
-	"encoding/binary"
 	"fmt"
-	"hash"
-	"io"
 	"io/ioutil"
 	"math/big"
-	"os"
 
 	Ed "crypto/ed25519"
-	"golang.org/x/crypto/scrypt"
-	"gopkg.in/yaml.v2"
 
-	"github.com/opencoff/go-utils"
+	"golang.org/x/crypto/scrypt"
+	"gopkg.in/yaml.v3"
 )
 
 // Private Ed25519 key
@@ -64,15 +59,10 @@ type PublicKey struct {
 	hash []byte
 }
 
-// Ed25519 key pair
-type Keypair struct {
-	Sec PrivateKey
-	Pub PublicKey
-}
-
 // Length of Ed25519 Public Key Hash
 const PKHashLength = 16
 
+// constants we use in this module
 const (
 	// Scrypt parameters
 	_N int = 1 << 19
@@ -118,55 +108,27 @@ type signature struct {
 	Signature string `yaml:"signature"`
 }
 
+// given a public key, generate a deterministic short-hash of it.
 func pkhash(pk []byte) []byte {
 	z := sha256.Sum256(pk)
 	return z[:PKHashLength]
 }
 
-// Generate a new Ed25519 keypair
+// NewPrivateKey generates a new Ed25519 private key
-func NewKeypair() (*Keypair, error) {
+func NewPrivateKey() (*PrivateKey, error) {
-	//kp := &Keypair{Sec: PrivateKey{N: 1 << 17, r: 64, p: 1}}
+	pkb, skb, err := Ed.GenerateKey(rand.Reader)
-	kp := &Keypair{}
-	sk := &kp.Sec
-	pk := &kp.Pub
-	sk.pk = pk
-
-	p, s, err := Ed.GenerateKey(rand.Reader)
 	if err != nil {
-		return nil, fmt.Errorf("Can't generate Ed25519 keys: %s", err)
+		return nil, err
 	}
 
-	pk.Pk = []byte(p)
+	sk := &PrivateKey{
-	sk.Sk = []byte(s)
+		Sk: []byte(skb),
-	pk.hash = pkhash(pk.Pk)
+		pk: &PublicKey{
-
+			Pk:   []byte(pkb),
-	return kp, nil
+			hash: pkhash([]byte(pkb)),
-}
+		},
-
-// Serialize the keypair to two separate files. The basename of the
-// file is 'bn'; the public key goes in $bn.pub and the private key
-// goes in $bn.key.
-// If password is non-empty, then the private key is encrypted
-// before writing to disk.
-func (kp *Keypair) Serialize(bn, comment string, getpw func() ([]byte, error)) error {
-
-	sk := &kp.Sec
-	pk := &kp.Pub
-
-	skf := fmt.Sprintf("%s.key", bn)
-	pkf := fmt.Sprintf("%s.pub", bn)
-
-	err := pk.serialize(pkf, comment)
-	if err != nil {
-		return fmt.Errorf("Can't serialize to %s: %s", pkf, err)
 	}
-
+	return sk, nil
-	err = sk.serialize(skf, comment, getpw)
-	if err != nil {
-		return fmt.Errorf("Can't serialize to %s: %s", pkf, err)
-	}
-
-	return nil
 }
 
 // Read the private key in 'fn', optionally decrypting it using
@@ -177,73 +139,30 @@ func ReadPrivateKey(fn string, getpw func() ([]byte, error)) (*PrivateKey, error
 		return nil, err
 	}
 
-	if bytes.Index(yml, []byte("OPENSSH PRIVATE KEY-")) > 0 {
+	var sk PrivateKey
-		return parseSSHPrivateKey(yml, getpw)
+	if err = sk.UnmarshalBinary(yml, getpw); err != nil {
+		return nil, err
 	}
-
+	return &sk, nil
-	if pw, err := getpw(); err == nil {
-		return MakePrivateKey(yml, pw)
-	}
-	return nil, err
 }
 
-// Make a private key from bytes 'yml' and password 'pw'. The bytes
+// Make a private key from bytes 'yml' using optional caller provided
+// getpw() function to read the password if needed.
 // are assumed to be serialized version of the private key.
-func MakePrivateKey(yml []byte, pw []byte) (*PrivateKey, error) {
+func MakePrivateKey(yml []byte, getpw func() ([]byte, error)) (*PrivateKey, error) {
-	var ssk serializedPrivKey
+	var sk PrivateKey
 
-	err := yaml.Unmarshal(yml, &ssk)
+	err := sk.UnmarshalBinary(yml, getpw)
 	if err != nil {
-		return nil, fmt.Errorf("make priv key: can't parse YAML: %s", err)
+		return nil, err
 	}
-
+	return &sk, nil
-	if len(ssk.Salt) == 0 || len(ssk.Esk) == 0 {
-		return nil, fmt.Errorf("sign: not YAML private key")
-	}
-
-	b64 := base64.StdEncoding.DecodeString
-
-	salt, err := b64(ssk.Salt)
-	if err != nil {
-		return nil, fmt.Errorf("make priv key: can't decode salt: %s", err)
-	}
-
-	esk, err := b64(ssk.Esk)
-	if err != nil {
-		return nil, fmt.Errorf("make priv key: can't decode key: %s", err)
-	}
-
-	// We take short passwords and extend them
-	pwb := sha512.Sum512(pw)
-
-	// "32" == Length of AES-256 key
-	key, err := scrypt.Key(pwb[:], salt, ssk.N, ssk.R, ssk.P, 32)
-	if err != nil {
-		return nil, fmt.Errorf("make priv key: can't derive key: %s", err)
-	}
-
-	aes, err := aes.NewCipher(key)
-	if err != nil {
-		return nil, fmt.Errorf("make priv key: aes failure: %s", err)
-	}
-
-	ae, err := cipher.NewGCM(aes)
-	if err != nil {
-		return nil, fmt.Errorf("make priv key: aes failure: %s", err)
-	}
-
-	skb, err := ae.Open(nil, salt[:ae.NonceSize()], esk, nil)
-	if err != nil {
-		return nil, fmt.Errorf("make priv key: wrong password")
-	}
-
-	return PrivateKeyFromBytes(skb)
 }
 
-// Make a private key from 64-bytes of extended Ed25519 key
+// make a PrivateKey from a byte array containing ed25519 raw SK
-func PrivateKeyFromBytes(buf []byte) (*PrivateKey, error) {
+func makePrivateKeyFromBytes(sk *PrivateKey, buf []byte) error {
 	if len(buf) != 64 {
-		return nil, fmt.Errorf("private key is malformed (len %d!)", len(buf))
+		return fmt.Errorf("private key is malformed (len %d!)", len(buf))
 	}
 
 	skb := make([]byte, 64)
@@ -256,12 +175,18 @@ func PrivateKeyFromBytes(buf []byte) (*PrivateKey, error) {
 		Pk:   []byte(edpk),
 		hash: pkhash([]byte(edpk)),
 	}
-	sk := &PrivateKey{
+	sk.Sk = skb
-		Sk: skb,
+	sk.pk = pk
-		pk: pk,
+	return nil
-	}
+}
 
-	return sk, nil
+// Make a private key from 64-bytes of extended Ed25519 key
+func PrivateKeyFromBytes(buf []byte) (*PrivateKey, error) {
+	var sk PrivateKey
+	if err := makePrivateKeyFromBytes(&sk, buf); err != nil {
+		return nil, err
+	}
+	return &sk, nil
 }
 
 // Given a secret key, return the corresponding Public Key
@@ -270,7 +195,7 @@ func (sk *PrivateKey) PublicKey() *PublicKey {
 }
 
 // Convert an Ed25519 Private Key to Curve25519 Private key
-func (sk *PrivateKey) toCurve25519SK() []byte {
+func (sk *PrivateKey) ToCurve25519SK() []byte {
 	if sk.ck == nil {
 		var ek [64]byte
 
@@ -284,12 +209,228 @@ func (sk *PrivateKey) toCurve25519SK() []byte {
 	return sk.ck
 }
 
+// Serialize the private key to file 'fn' using human readable
+// 'comment' and encrypt the key with supplied passphrase 'pw'.
+func (sk *PrivateKey) Serialize(fn, comment string, ovwrite bool, pw []byte) error {
+	b, err := sk.MarshalBinary(comment, pw)
+	if err == nil {
+		return writeFile(fn, b, ovwrite, 0600)
+	}
+	return err
+}
+
+// MarshalBinary marshals the private key with a caller provided
+// passphrase 'pw' and human readable 'comment'
+func (sk *PrivateKey) MarshalBinary(comment string, pw []byte) ([]byte, error) {
+	// expand the password into 64 bytes
+	pass := sha512.Sum512(pw)
+	salt := make([]byte, 32)
+
+	randRead(salt)
+
+	// "32" == Length of AES-256 key
+	key, err := scrypt.Key(pass[:], salt, _N, _r, _p, 32)
+	if err != nil {
+		return nil, fmt.Errorf("marshal: can't derive scrypt key: %s", err)
+	}
+
+	aes, err := aes.NewCipher(key)
+	if err != nil {
+		return nil, fmt.Errorf("marshal: %s", err)
+	}
+
+	ae, err := cipher.NewGCM(aes)
+	if err != nil {
+		return nil, fmt.Errorf("marshal: %s", err)
+	}
+
+	tl := ae.Overhead()
+	buf := make([]byte, tl+len(sk.Sk))
+	esk := ae.Seal(buf[:0], salt[:ae.NonceSize()], sk.Sk, nil)
+
+	enc := base64.StdEncoding.EncodeToString
+
+	ssk := serializedPrivKey{
+		Comment: comment,
+		Esk:     enc(esk),
+		Salt:    enc(salt),
+		Algo:    sk_algo,
+		N:       _N,
+		R:       _r,
+		P:       _p,
+	}
+
+	// We won't protect the Scrypt parameters with the hash above
+	// because it is not needed. If the parameters are wrong, the
+	// derived key will be wrong and thus, the hash will not match.
+
+	return yaml.Marshal(&ssk)
+}
+
+// UnmarshalBinary unmarshals the private key and optionally invokes the
+// caller provided getpw() function to read the password if needed. If the
+// input byte stream 'b' is an OpenSSH ed25519 key, this function transparently
+// decodes it.
+func (sk *PrivateKey) UnmarshalBinary(b []byte, getpw func() ([]byte, error)) error {
+	if bytes.Index(b, []byte("OPENSSH PRIVATE KEY-")) > 0 {
+		xk, err := parseSSHPrivateKey(b, getpw)
+		if err != nil {
+			return err
+		}
+		*sk = *xk
+		return nil
+	}
+
+	var pw []byte
+	if getpw != nil {
+		var err error
+		pw, err = getpw()
+		if err != nil {
+			return err
+		}
+	}
+
+	// We take short passwords and extend them
+	pwb := sha512.Sum512(pw)
+
+	var ssk serializedPrivKey
+
+	err := yaml.Unmarshal(b, &ssk)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: can't parse YAML: %s", err)
+	}
+
+	if len(ssk.Salt) == 0 || len(ssk.Esk) == 0 {
+		return fmt.Errorf("unmarshal priv key: not YAML format")
+	}
+
+	b64 := base64.StdEncoding.DecodeString
+
+	salt, err := b64(ssk.Salt)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: can't decode salt: %s", err)
+	}
+
+	esk, err := b64(ssk.Esk)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: can't decode key: %s", err)
+	}
+
+	// "32" == Length of AES-256 key
+	key, err := scrypt.Key(pwb[:], salt, ssk.N, ssk.R, ssk.P, 32)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: can't derive key: %s", err)
+	}
+
+	aes, err := aes.NewCipher(key)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: aes failure: %s", err)
+	}
+
+	ae, err := cipher.NewGCM(aes)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: aes failure: %s", err)
+	}
+
+	skb := make([]byte, 64)
+	skb, err = ae.Open(skb[:0], salt[:ae.NonceSize()], esk, nil)
+	if err != nil {
+		return fmt.Errorf("unmarshal priv key: wrong password")
+	}
+
+	return makePrivateKeyFromBytes(sk, skb)
+}
+
+//  --- Public Key Methods ---
+
+// Read the public key from 'fn' and create new instance of
+// PublicKey
+func ReadPublicKey(fn string) (*PublicKey, error) {
+	var err error
+	var yml []byte
+
+	if yml, err = ioutil.ReadFile(fn); err != nil {
+		return nil, err
+	}
+
+	var pk PublicKey
+	if err = pk.UnmarshalBinary(yml); err != nil {
+		return nil, err
+	}
+	return &pk, nil
+}
+
+// Parse a serialized public in 'yml' and return the resulting
+// public key instance
+func MakePublicKey(yml []byte) (*PublicKey, error) {
+	var pk PublicKey
+	if err := pk.UnmarshalBinary(yml); err != nil {
+		return nil, err
+	}
+	return &pk, nil
+}
+
+// Make a public key from a string
+func MakePublicKeyFromString(s string) (*PublicKey, error) {
+	// first try to decode it as a openssh key
+	if pk2, err := parseEncPubKey([]byte(s), "command-line-pk"); err == nil {
+		return pk2, nil
+	}
+
+	// Now try to decode as an sigtool key
+	b64 := base64.StdEncoding.DecodeString
+
+	pkb, err := b64(s)
+	if err != nil {
+		return nil, err
+	}
+
+	var pk PublicKey
+	err = makePublicKeyFromBytes(&pk, pkb)
+	if err != nil {
+		return nil, err
+	}
+	return &pk, nil
+}
+
+func makePublicKeyFromBytes(pk *PublicKey, b []byte) error {
+	if len(b) != 32 {
+		return fmt.Errorf("public key is malformed (len %d!)", len(b))
+	}
+
+	pk.Pk = make([]byte, 32)
+	pk.hash = pkhash(b)
+	copy(pk.Pk, b)
+
+	return nil
+}
+
+// Make a public key from a byte string
+func PublicKeyFromBytes(b []byte) (*PublicKey, error) {
+	var pk PublicKey
+	if err := makePublicKeyFromBytes(&pk, b); err != nil {
+		return nil, err
+	}
+	return &pk, nil
+}
+
+// Serialize a PublicKey into file 'fn' with a human readable 'comment'.
+// If 'ovwrite' is true, overwrite the file if it exists.
+func (pk *PublicKey) Serialize(fn, comment string, ovwrite bool) error {
+	out, err := pk.MarshalBinary(comment)
+	if err == nil {
+		return writeFile(fn, out, ovwrite, 0644)
+	}
+
+	return err
+}
+
 // from github.com/FiloSottile/age
 var curve25519P, _ = new(big.Int).SetString("57896044618658097711785492504343953926634992332820282019728792003956564819949", 10)
 
 // Convert an Ed25519 Public Key to Curve25519 public key
 // from github.com/FiloSottile/age
-func (pk *PublicKey) toCurve25519PK() []byte {
+func (pk *PublicKey) ToCurve25519PK() []byte {
 	if pk.ck != nil {
 		return pk.ck
 	}
@@ -329,131 +470,8 @@ func (pk *PublicKey) Hash() []byte {
 	return pk.hash
 }
 
-// Serialize the private key to a file
+// MarshalBinary marshals a PublicKey into a byte array
-// AEAD encryption for protecting the private key
+func (pk *PublicKey) MarshalBinary(comment string) ([]byte, error) {
-// Format: YAML
-// All []byte are in base64 (RawEncoding)
-func (sk *PrivateKey) serialize(fn, comment string, getpw func() ([]byte, error)) error {
-	pw, err := getpw()
-	if err != nil {
-		return err
-	}
-
-	// expand the password into 64 bytes
-	pass := sha512.Sum512(pw)
-	salt := make([]byte, 32)
-
-	randRead(salt)
-
-	// "32" == Length of AES-256 key
-	key, err := scrypt.Key(pass[:], salt, _N, _r, _p, 32)
-	if err != nil {
-		return fmt.Errorf("marshal: can't derive scrypt key: %s", err)
-	}
-
-	aes, err := aes.NewCipher(key)
-	if err != nil {
-		return fmt.Errorf("marshal: %s", err)
-	}
-
-	ae, err := cipher.NewGCM(aes)
-	if err != nil {
-		return fmt.Errorf("marshal: %s", err)
-	}
-
-	tl := ae.Overhead()
-	buf := make([]byte, tl+len(sk.Sk))
-	esk := ae.Seal(buf[:0], salt[:ae.NonceSize()], sk.Sk, nil)
-
-	enc := base64.StdEncoding.EncodeToString
-
-	ssk := serializedPrivKey{
-		Comment: comment,
-		Esk:     enc(esk),
-		Salt:    enc(salt),
-		Algo:    sk_algo,
-		N:       _N,
-		R:       _r,
-		P:       _p,
-	}
-
-	// We won't protect the Scrypt parameters with the hash above
-	// because it is not needed. If the parameters are wrong, the
-	// derived key will be wrong and thus, the hash will not match.
-
-	out, err := yaml.Marshal(&ssk)
-	if err != nil {
-		return fmt.Errorf("can't marahal to YAML: %s", err)
-	}
-
-	return writeFile(fn, out, 0600)
-}
-
-//  --- Public Key Methods ---
-
-// Read the public key from 'fn' and create new instance of
-// PublicKey
-func ReadPublicKey(fn string) (*PublicKey, error) {
-	var err error
-	var yml []byte
-
-	if yml, err = ioutil.ReadFile(fn); err != nil {
-		return nil, err
-	}
-
-	// first try to parse as a ssh key
-	pk, err := parseSSHPublicKey(yml)
-	if err != nil {
-		pk, err = MakePublicKey(yml)
-	}
-	return pk, err
-}
-
-// Parse a serialized public in 'yml' and return the resulting
-// public key instance
-func MakePublicKey(yml []byte) (*PublicKey, error) {
-	var spk serializedPubKey
-	var err error
-
-	if err = yaml.Unmarshal(yml, &spk); err != nil {
-		return nil, fmt.Errorf("can't parse YAML: %s", err)
-	}
-
-	if len(spk.Pk) == 0 {
-		return nil, fmt.Errorf("sign: not a YAML public key")
-	}
-
-	b64 := base64.StdEncoding.DecodeString
-	var pkb []byte
-
-	if pkb, err = b64(spk.Pk); err != nil {
-		return nil, fmt.Errorf("can't decode YAML:Pk: %s", err)
-	}
-
-	if pk, err := PublicKeyFromBytes(pkb); err == nil {
-		pk.Comment = spk.Comment
-		return pk, nil
-	}
-	return nil, err
-}
-
-// Make a public key from a byte string
-func PublicKeyFromBytes(b []byte) (*PublicKey, error) {
-	if len(b) != 32 {
-		return nil, fmt.Errorf("public key is malformed (len %d!)", len(b))
-	}
-
-	pk := &PublicKey{
-		Pk:   make([]byte, 32),
-		hash: pkhash(b),
-	}
-
-	copy(pk.Pk, b)
-	return pk, nil
-}
-
-// Serialize Public Keys
-func (pk *PublicKey) serialize(fn, comment string) error {
 	b64 := base64.StdEncoding.EncodeToString
 	spk := &serializedPubKey{
 		Comment: comment,
@@ -461,76 +479,45 @@ func (pk *PublicKey) serialize(fn, comment string) error {
 		Hash:    b64(pk.hash),
 	}
 
-	out, err := yaml.Marshal(spk)
+	return yaml.Marshal(spk)
-	if err != nil {
+}
-		return fmt.Errorf("can't marahal to YAML: %s", err)
+
+// UnmarshalBinary constructs a PublicKey from a previously
+// marshaled byte stream instance. In addition, it is also
+// capable of parsing an OpenSSH ed25519 public key.
+func (pk *PublicKey) UnmarshalBinary(yml []byte) error {
+
+	// first try to parse as a ssh key
+	if xk, err := parseSSHPublicKey(yml); err == nil {
+		*pk = *xk
+		return nil
 	}
 
-	return writeFile(fn, out, 0644)
+	// OK Yaml it is.
+
+	var spk serializedPubKey
+	var err error
+
+	if err = yaml.Unmarshal(yml, &spk); err != nil {
+		return fmt.Errorf("can't parse YAML: %s", err)
+	}
+
+	if len(spk.Pk) == 0 {
+		return fmt.Errorf("sign: not a YAML public key")
+	}
+
+	b64 := base64.StdEncoding.DecodeString
+	var pkb []byte
+
+	if pkb, err = b64(spk.Pk); err != nil {
+		return fmt.Errorf("can't decode YAML:Pk: %s", err)
+	}
+
+	return makePublicKeyFromBytes(pk, pkb)
 }
 
 // -- Internal Utility Functions --
 
-// Unlink a file.
-func unlink(f string) {
-	st, err := os.Stat(f)
-	if err == nil {
-		if !st.Mode().IsRegular() {
-			panic(fmt.Sprintf("%s can't be unlinked. Not a regular file?", f))
-		}
-
-		os.Remove(f)
-		return
-	}
-}
-
-// Simple function to reliably write data to a file.
-// Does MORE than ioutil.WriteFile() - in that it doesn't trash the
-// existing file with an incomplete write.
-func writeFile(fn string, b []byte, mode uint32) error {
-	tmp := fmt.Sprintf("%s.tmp", fn)
-	unlink(tmp)
-
-	fd, err := os.OpenFile(tmp, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, os.FileMode(mode))
-	if err != nil {
-		return fmt.Errorf("Can't create file %s: %s", tmp, err)
-	}
-
-	_, err = fd.Write(b)
-	if err != nil {
-		fd.Close()
-		// XXX Do we delete the tmp file?
-		return fmt.Errorf("Can't write %v bytes to %s: %s", len(b), tmp, err)
-	}
-
-	fd.Close() // we ignore close(2) errors; unrecoverable anyway.
-
-	os.Rename(tmp, fn)
-	return nil
-}
-
-// Generate file checksum out of hash function h
-func fileCksum(fn string, h hash.Hash) ([]byte, error) {
-
-	fd, err := os.Open(fn)
-	if err != nil {
-		return nil, fmt.Errorf("can't open %s: %s", fn, err)
-	}
-
-	defer fd.Close()
-
-	sz, err := utils.MmapReader(fd, 0, 0, h)
-	if err != nil {
-		return nil, err
-	}
-
-	var b [8]byte
-	binary.BigEndian.PutUint64(b[:], uint64(sz))
-	h.Write(b[:])
-
-	return h.Sum(nil), nil
-}
-
 func clamp(k []byte) []byte {
 	k[0] &= 248
 	k[31] &= 127
@@ -538,13 +525,5 @@ func clamp(k []byte) []byte {
 	return k
 }
 
-func randRead(b []byte) []byte {
-	_, err := io.ReadFull(rand.Reader, b)
-	if err != nil {
-		panic(fmt.Sprintf("can't read %d bytes of random data: %s", len(b), err))
-	}
-	return b
-}
-
 // EOF
 // vim: noexpandtab:ts=8:sw=8:tw=92:

sign/rand.go

@@ -0,0 +1,45 @@
+// rand.go - utility functions to generate random quantities
+//
+// (c) 2018 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package sign
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"fmt"
+	"io"
+)
+
+func randu32() uint32 {
+	var b [4]byte
+
+	_, err := io.ReadFull(rand.Reader, b[:])
+	if err != nil {
+		panic(fmt.Sprintf("can't read 4 rand bytes: %s", err))
+	}
+
+	return binary.LittleEndian.Uint32(b[:])
+}
+
+func randRead(b []byte) []byte {
+	_, err := io.ReadFull(rand.Reader, b)
+	if err != nil {
+		panic(fmt.Sprintf("can't read %d bytes of random data: %s", len(b), err))
+	}
+	return b
+}
+
+func randBuf(sz int) []byte {
+	b := make([]byte, sz)
+	return randRead(b)
+}

sign/sign.go

@@ -27,7 +27,8 @@ import (
 	"io/ioutil"
 
 	Ed "crypto/ed25519"
-	"gopkg.in/yaml.v2"
+
+	"gopkg.in/yaml.v3"
 )
 
 // An Ed25519 Signature
@@ -38,8 +39,9 @@ type Signature struct {
 
 // Sign a prehashed Message; return the signature as opaque bytes
 // Signature is an YAML file:
-//    Comment: source file path
+//
-//    Signature: Ed25519 signature
+//	Comment: source file path
+//	Signature: Ed25519 signature
 func (sk *PrivateKey) SignMessage(ck []byte, comment string) (*Signature, error) {
 	h := sha512.New()
 	h.Write([]byte("sigtool signed message"))
@@ -86,12 +88,13 @@ func ReadSignature(fn string) (*Signature, error) {
 		return nil, err
 	}
 
-	return MakeSignature(yml)
+	var sig Signature
+	return makeSignature(&sig, yml)
 }
 
 // Parse serialized signature from bytes 'b' and construct a
 // Signature object
-func MakeSignature(b []byte) (*Signature, error) {
+func makeSignature(sig *Signature, b []byte) (*Signature, error) {
 	var ss signature
 	err := yaml.Unmarshal(b, &ss)
 	if err != nil {
@@ -110,29 +113,33 @@ func MakeSignature(b []byte) (*Signature, error) {
 		return nil, fmt.Errorf("can't decode Base64:Pkhash <%s>: %s", ss.Pkhash, err)
 	}
 
-	return &Signature{Sig: s, pkhash: p}, nil
+	sig.Sig = s
+	sig.pkhash = p
+	return sig, nil
 }
 
-// Serialize a signature suitable for storing in durable media
+// MarshalBinary marshals a signature into a byte stream with
-func (sig *Signature) Serialize(comment string) ([]byte, error) {
+// an optional caller supplied comment.
-
+func (sig *Signature) MarshalBinary(comment string) ([]byte, error) {
 	sigs := base64.StdEncoding.EncodeToString(sig.Sig)
 	pks := base64.StdEncoding.EncodeToString(sig.pkhash)
 	ss := &signature{Comment: comment, Pkhash: pks, Signature: sigs}
 
-	out, err := yaml.Marshal(ss)
+	return yaml.Marshal(ss)
-	if err != nil {
-		return nil, fmt.Errorf("can't marshal signature of %x to YAML: %s", sig.Sig, err)
-	}
-
-	return out, nil
 }
 
-// SerializeFile serializes the signature to an output file 'f'
+// UnmarshalBinary constructs a Signature from a previously
-func (sig *Signature) SerializeFile(fn, comment string) error {
+// serialized bytestream
-	b, err := sig.Serialize(comment)
+func (sig *Signature) UnmarshalBinary(b []byte) error {
+	_, err := makeSignature(sig, b)
+	return err
+}
+
+// Serialize a signature suitable for storing in durable media
+func (sig *Signature) Serialize(fn, comment string, ovwrite bool) error {
+	b, err := sig.MarshalBinary(comment)
 	if err == nil {
-		err = writeFile(fn, b, 0644)
+		err = writeFile(fn, b, ovwrite, 0644)
 	}
 	return err
 }
@@ -147,7 +154,6 @@ func (sig *Signature) IsPKMatch(pk *PublicKey) bool {
 // Verify a signature 'sig' for file 'fn' against public key 'pk'
 // Return True if signature matches, False otherwise
 func (pk *PublicKey) VerifyFile(fn string, sig *Signature) (bool, error) {
-
 	ck, err := fileCksum(fn, sha512.New())
 	if err != nil {
 		return false, err

sign/sign_test.go

@@ -38,16 +38,20 @@ func tempdir(t *testing.T) string {
 	return tmp
 }
 
+var fixedPw = []byte("abc")
+var badPw = []byte("def")
+var nilPw []byte
+
 // return a hardcoded password
 func hardcodedPw() ([]byte, error) {
-	return []byte("abc"), nil
+	return fixedPw, nil
 }
 
 func wrongPw() ([]byte, error) {
-	return []byte("xyz"), nil
+	return badPw, nil
 }
 func emptyPw() ([]byte, error) {
-	return nil, nil
+	return nilPw, nil
 }
 
 // Return true if file exists, false otherwise
@@ -80,68 +84,78 @@ p: 1
 func TestSignSimple(t *testing.T) {
 	assert := newAsserter(t)
 
-	kp, err := NewKeypair()
+	sk, err := NewPrivateKey()
-	assert(err == nil, "NewKeyPair() fail")
+	assert(err == nil, "NewPrivateKey() fail")
 
-	dn := tempdir(t)
+	pk := sk.PublicKey()
+
+	dn := t.TempDir()
 	bn := fmt.Sprintf("%s/t0", dn)
 
-	err = kp.Serialize(bn, "", hardcodedPw)
-	assert(err == nil, "keyPair.Serialize() fail")
-
 	pkf := fmt.Sprintf("%s.pub", bn)
 	skf := fmt.Sprintf("%s.key", bn)
 
-	// We must find these two files
+	err = pk.Serialize(pkf, "", true)
-	assert(fileExists(pkf), "missing pkf")
+	assert(err == nil, "can't serialize pk %s", pkf)
-	assert(fileExists(skf), "missing skf")
 
-	pk, err := ReadPublicKey(pkf)
+	// try to overwrite
+	err = pk.Serialize(pkf, "", false)
+	assert(err != nil, "pk %s overwritten!", pkf)
+
+	err = sk.Serialize(skf, "", true, fixedPw)
+	assert(err == nil, "can't serialize sk %s", skf)
+
+	err = sk.Serialize(skf, "", false, nilPw)
+	assert(err != nil, "sk %s overwritten!", skf)
+
+	// We must find these two files
+	assert(fileExists(pkf), "missing pkf %s", pkf)
+	assert(fileExists(skf), "missing skf %s", skf)
+
+	npk, err := ReadPublicKey(pkf)
 	assert(err == nil, "ReadPK() fail")
 
-	// -ditto- for Sk
+	// send the public key as private key
-	sk, err := ReadPrivateKey(pkf, emptyPw)
+	nsk, err := ReadPrivateKey(pkf, emptyPw)
 	assert(err != nil, "bad SK ReadSK fail: %s", err)
 
-	sk, err = ReadPrivateKey(skf, emptyPw)
+	nsk, err = ReadPrivateKey(skf, emptyPw)
-	assert(err != nil, "ReadSK() empty pw fail:  ks", err)
+	assert(err != nil, "ReadSK() worked with empty pw")
 
-	sk, err = ReadPrivateKey(skf, wrongPw)
+	nsk, err = ReadPrivateKey(skf, wrongPw)
-	assert(err != nil, "ReadSK() wrong pw fail: %s", err)
+	assert(err != nil, "ReadSK() worked with wrong pw")
 
 	badf := fmt.Sprintf("%s/badf.key", dn)
 	err = ioutil.WriteFile(badf, []byte(badsk), 0600)
-	assert(err == nil, "write badsk")
+	assert(err == nil, "can't write badsk: %s", err)
 
-	sk, err = ReadPrivateKey(badf, hardcodedPw)
+	nsk, err = ReadPrivateKey(badf, hardcodedPw)
-	assert(err != nil, "badsk read fail: %s", err)
+	assert(err != nil, "decoded bad SK")
 
 	// Finally, with correct password it should work.
-	sk, err = ReadPrivateKey(skf, hardcodedPw)
+	nsk, err = ReadPrivateKey(skf, hardcodedPw)
-	assert(err == nil, "ReadSK() correct pw fail")
+	assert(err == nil, "ReadSK() correct pw fail: %s", err)
 
 	// And, deserialized keys should be identical
-	assert(byteEq(pk.Pk, kp.Pub.Pk), "pkbytes unequal")
+	assert(byteEq(pk.Pk, npk.Pk), "pkbytes unequal")
-	assert(byteEq(sk.Sk, kp.Sec.Sk), "skbytes unequal")
+	assert(byteEq(sk.Sk, nsk.Sk), "skbytes unequal")
-
-	os.RemoveAll(dn)
 }
 
 // #2. Create new key pair, sign a rand buffer and verify
 func TestSignRandBuf(t *testing.T) {
 	assert := newAsserter(t)
-	kp, err := NewKeypair()
+
-	assert(err == nil, "NewKeyPair() fail")
+	sk, err := NewPrivateKey()
+	assert(err == nil, "NewPrivateKey() fail: %s", err)
 
 	var ck [64]byte // simulates sha512 sum
 
 	randRead(ck[:])
 
-	pk := &kp.Pub
+	pk := sk.PublicKey()
-	sk := &kp.Sec
 
 	ss, err := sk.SignMessage(ck[:], "")
-	assert(err == nil, "sk.sign fail")
+	assert(err == nil, "sk.sign fail: %s", err)
 	assert(ss != nil, "sig is null")
 
 	// verify sig
@@ -160,27 +174,13 @@ func TestSignRandBuf(t *testing.T) {
 	assert(ok, "verify fail")
 
 	// Now sign a file
-	dn := tempdir(t)
+	dn := t.TempDir()
-	bn := fmt.Sprintf("%s/k", dn)
-
-	pkf := fmt.Sprintf("%s.pub", bn)
-	skf := fmt.Sprintf("%s.key", bn)
-
-	err = kp.Serialize(bn, "", emptyPw)
-	assert(err == nil, "keyPair.Serialize() fail")
-
-	// Now read the private key and sign
-	sk, err = ReadPrivateKey(skf, emptyPw)
-	assert(err == nil, "readSK fail")
-
-	pk, err = ReadPublicKey(pkf)
-	assert(err == nil, "ReadPK fail")
 
 	var buf [8192]byte
 
 	zf := fmt.Sprintf("%s/file.dat", dn)
 	fd, err := os.OpenFile(zf, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, 0600)
-	assert(err == nil, "file.dat creat file")
+	assert(err == nil, "file.dat creat file: %s", err)
 
 	for i := 0; i < 8; i++ {
 		randRead(buf[:])
@@ -192,27 +192,31 @@ func TestSignRandBuf(t *testing.T) {
 	fd.Close()
 
 	sig, err := sk.SignFile(zf)
-	assert(err == nil, "file.dat sign fail")
+	assert(err == nil, "file.dat sign fail: %s", err)
 	assert(sig != nil, "file.dat sign nil")
 
 	ok, err = pk.VerifyFile(zf, sig)
-	assert(err == nil, "file.dat verify fail")
+	assert(err == nil, "file.dat verify fail: %s", err)
 	assert(ok, "file.dat verify false")
 
 	// Now, serialize the signature and read it back
 	sf := fmt.Sprintf("%s/file.sig", dn)
-	err = sig.SerializeFile(sf, "")
+	err = sig.Serialize(sf, "", true)
-	assert(err == nil, "sig serialize fail")
+	assert(err == nil, "sig serialize fail: %s", err)
+
+	// now try to overwrite it
+	err = sig.Serialize(sf, "", false)
+	assert(err != nil, "sig serialize overwrote?!")
 
 	s2, err := ReadSignature(sf)
-	assert(err == nil, "file.sig read fail")
+	assert(err == nil, "file.sig read fail: %s", err)
 	assert(s2 != nil, "file.sig sig nil")
 
 	assert(byteEq(s2.Sig, sig.Sig), "sig compare fail")
 
 	// If we give a wrong file, verify must fail
 	st, err := os.Stat(zf)
-	assert(err == nil, "file.dat stat fail")
+	assert(err == nil, "file.dat stat fail: %s", err)
 
 	n := st.Size()
 	assert(n == 8192*8, "file.dat size fail")
@@ -220,12 +224,12 @@ func TestSignRandBuf(t *testing.T) {
 	os.Truncate(zf, n-1)
 
 	st, err = os.Stat(zf)
-	assert(err == nil, "file.dat stat2 fail")
+	assert(err == nil, "file.dat stat2 fail: %s", err)
 	assert(st.Size() == (n-1), "truncate fail")
 
 	// Now verify this corrupt file
 	ok, err = pk.VerifyFile(zf, sig)
-	assert(err == nil, "file.dat corrupt i/o fail")
+	assert(err == nil, "file.dat corrupt i/o fail: %s", err)
 	assert(!ok, "file.dat corrupt verify false")
 
 	os.RemoveAll(dn)
@@ -233,7 +237,7 @@ func TestSignRandBuf(t *testing.T) {
 
 func Benchmark_Keygen(b *testing.B) {
 	for i := 0; i < b.N; i++ {
-		_, _ = NewKeypair()
+		_, _ = NewPrivateKey()
 	}
 }
 
@@ -250,7 +254,8 @@ func Benchmark_Sig(b *testing.B) {
 	}
 
 	b.StopTimer()
-	kp, _ := NewKeypair()
+	sk, _ := NewPrivateKey()
+	pk := sk.PublicKey()
 	var sig *Signature
 	for _, sz := range sizes {
 		buf := randbuf(sz)
@@ -260,11 +265,11 @@ func Benchmark_Sig(b *testing.B) {
 		b.ResetTimer()
 
 		b.Run(s0, func(b *testing.B) {
-			sig = benchSign(b, buf, &kp.Sec)
+			sig = benchSign(b, buf, sk)
 		})
 
 		b.Run(s1, func(b *testing.B) {
-			benchVerify(b, buf, sig, &kp.Pub)
+			benchVerify(b, buf, sig, pk)
 		})
 	}
 }

sign/ssh.go

@@ -26,6 +26,7 @@ import (
 	"encoding/binary"
 	"encoding/pem"
 	"fmt"
+	"regexp"
 	"strings"
 
 	"github.com/dchest/bcrypt_pbkdf"
@@ -56,12 +57,13 @@ func parseSSHPrivateKey(data []byte, getpw func() ([]byte, error)) (*PrivateKey,
 }
 
 func parseSSHPublicKey(in []byte) (*PublicKey, error) {
-	v := bytes.Split(in, []byte(" \t"))
+	splitter := regexp.MustCompile("[ \\t]+")
+	v := splitter.Split(string(in), -1)
 	if len(v) != 3 {
 		return nil, ErrBadPublicKey
 	}
 
-	return parseEncPubKey(v[1], string(v[2]))
+	return parseEncPubKey([]byte(v[1]), v[2])
 }
 
 // parse a wire encoded public key
@@ -93,11 +95,13 @@ func parseEncPubKey(in []byte, comm string) (*PublicKey, error) {
 		return nil, ErrBadTrailers
 	}
 
-	pk, err := PublicKeyFromBytes(w.KeyBytes)
+	var pk PublicKey
-	if err == nil {
+
+	if err = makePublicKeyFromBytes(&pk, w.KeyBytes); err == nil {
 		pk.Comment = strings.TrimSpace(comm)
+		return &pk, nil
 	}
-	return pk, err
+	return nil, err
 }
 
 func parseString(in []byte) (out, rest []byte, ok bool) {
@@ -341,8 +345,11 @@ func parseOpenSSHPrivateKey(data []byte, getpw func() ([]byte, error)) (*Private
 			}
 		}
 
-		pk, err := PrivateKeyFromBytes(key.Priv)
+		var sk PrivateKey
-		return pk, err
+		if err = makePrivateKeyFromBytes(&sk, key.Priv); err == nil {
+			return &sk, nil
+		}
+		return nil, err
 	default:
 		return nil, fmt.Errorf("ssh: unhandled key type: %v", pk1.Keytype)
 	}

sign/stream.go

@@ -29,6 +29,8 @@ type encWriter struct {
 	err error
 }
 
+var _ io.WriteCloser = &encWriter{}
+
 // NewStreamWriter begins stream encryption to an underlying destination writer 'wr'.
 // It returns an io.WriteCloser.
 func (e *Encryptor) NewStreamWriter(wr io.WriteCloser) (io.WriteCloser, error) {
@@ -108,6 +110,8 @@ type encReader struct {
 	blk    uint32
 }
 
+var _ io.Reader = &encReader{}
+
 // NewStreamReader returns an io.Reader to read from the decrypted stream
 func (d *Decryptor) NewStreamReader() (io.Reader, error) {
 	if d.key == nil {

sigtool.go

@@ -1,362 +0,0 @@
-// sigtool.go -- Tool to generate, manage Ed25519 keys and
-// signatures.
-//
-// (c) 2016 Sudhi Herle <sudhi@herle.net>
-//
-// Licensing Terms: GPLv2
-//
-// If you need a commercial license for this work, please contact
-// the author.
-//
-// This software does not come with any express or implied
-// warranty; it is provided "as is". No claim  is made to its
-// suitability for any purpose.
-
-package main
-
-import (
-	"fmt"
-	"io"
-	"os"
-	"path"
-	"strings"
-
-	"github.com/opencoff/go-utils"
-	flag "github.com/opencoff/pflag"
-	"github.com/opencoff/sigtool/sign"
-)
-
-var Z string = path.Base(os.Args[0])
-
-func main() {
-
-	var ver, help bool
-
-	mf := flag.NewFlagSet(Z, flag.ExitOnError)
-	mf.SetInterspersed(false)
-	mf.BoolVarP(&ver, "version", "v", false, "Show version info and exit")
-	mf.BoolVarP(&help, "help", "h", false, "Show help info exit")
-	mf.Parse(os.Args[1:])
-
-	if ver {
-		fmt.Printf("%s - %s [%s; %s]\n", Z, ProductVersion, RepoVersion, Buildtime)
-		os.Exit(0)
-	}
-
-	if help {
-		usage(0)
-	}
-
-	args := mf.Args()
-	if len(args) < 1 {
-		warn("Insufficient arguments. Try '%s -h'", Z)
-		os.Exit(1)
-	}
-
-	cmds := map[string]func(args []string){
-		"generate": gen,
-		"sign":     signify,
-		"verify":   verify,
-		"encrypt":  encrypt,
-		"decrypt":  decrypt,
-
-		"help": func(_ []string) {
-			usage(0)
-		},
-	}
-
-	words := make([]string, 0, len(cmds))
-	for k := range cmds {
-		words = append(words, k)
-	}
-
-	ab := utils.Abbrev(words)
-	canon, ok := ab[strings.ToLower(args[0])]
-	if !ok {
-		die("Unknown command %s", args[0])
-	}
-
-	cmd := cmds[canon]
-	if cmd == nil {
-		die("can't map command %s", canon)
-	}
-
-	cmd(args[1:])
-}
-
-// Run the generate command
-func gen(args []string) {
-
-	var nopw, help, force bool
-	var comment string
-	var envpw string
-
-	fs := flag.NewFlagSet("generate", flag.ExitOnError)
-	fs.BoolVarP(&help, "help", "h", false, "Show this help and exit")
-	fs.BoolVarP(&nopw, "no-password", "", false, "Don't ask for a password for the private key")
-	fs.StringVarP(&comment, "comment", "c", "", "Use `C` as the text comment for the keys")
-	fs.StringVarP(&envpw, "env-password", "E", "", "Use passphrase from environment variable `E`")
-	fs.BoolVarP(&force, "force", "F", false, "Overwrite the output file if it exists")
-
-	fs.Parse(args)
-
-	if help {
-		fs.SetOutput(os.Stdout)
-		fmt.Printf(`%s generate|gen|g [options] file-prefix
-
-Generate a new Ed25519 public+private key pair and write public key to
-FILE-PREFIX.pub and private key to FILE-PREFIX.key.
-
-Options:
-`, Z)
-		fs.PrintDefaults()
-		os.Exit(0)
-	}
-
-	args = fs.Args()
-	if len(args) < 1 {
-		die("Insufficient arguments to 'generate'. Try '%s generate -h' ..", Z)
-	}
-
-	bn := args[0]
-
-	if exists(bn) && !force {
-		die("Public/Private key files (%s.key, %s.pub) exist. Won't overwrite!", bn, bn)
-	}
-
-	var err error
-
-	kp, err := sign.NewKeypair()
-	if err != nil {
-		die("%s", err)
-	}
-
-	err = kp.Serialize(bn, comment, func() ([]byte, error) {
-		if nopw {
-			return nil, nil
-		}
-
-		var pws string
-		if len(envpw) > 0 {
-			pws = os.Getenv(envpw)
-		} else {
-			pws, err = utils.Askpass("Enter passphrase for private key", true)
-			if err != nil {
-				die("%s", err)
-			}
-		}
-		return []byte(pws), nil
-	})
-	if err != nil {
-		die("%s", err)
-	}
-}
-
-// Run the 'sign' command.
-func signify(args []string) {
-	var nopw, help bool
-	var output string
-	var envpw string
-
-	fs := flag.NewFlagSet("sign", flag.ExitOnError)
-	fs.BoolVarP(&help, "help", "h", false, "Show this help and exit")
-	fs.BoolVarP(&nopw, "no-password", "", false, "Don't ask for a password for the private key")
-	fs.StringVarP(&envpw, "env-password", "E", "", "Use passphrase from environment variable `E`")
-	fs.StringVarP(&output, "output", "o", "", "Write signature to file `F`")
-
-	fs.Parse(args)
-
-	if help {
-		fs.SetOutput(os.Stdout)
-		fmt.Printf(`%s sign|s [options] privkey file
-
-Sign FILE with a Ed25519 private key PRIVKEY and write signature to FILE.sig
-
-Options:
-`, Z)
-		fs.PrintDefaults()
-		os.Exit(0)
-	}
-
-	args = fs.Args()
-	if len(args) < 2 {
-		die("Insufficient arguments to 'sign'. Try '%s sign -h' ..", Z)
-	}
-
-	kn := args[0]
-	fn := args[1]
-	outf := fmt.Sprintf("%s.sig", fn)
-
-	var err error
-
-	if len(output) > 0 {
-		outf = output
-	}
-
-	sk, err := sign.ReadPrivateKey(kn, func() ([]byte, error) {
-		if nopw {
-			return nil, nil
-		}
-
-		var pws string
-		if len(envpw) > 0 {
-			pws = os.Getenv(envpw)
-		} else {
-			pws, err = utils.Askpass("Enter passphrase for private key", false)
-			if err != nil {
-				die("%s", err)
-			}
-		}
-
-		return []byte(pws), nil
-	})
-	if err != nil {
-		die("%s", err)
-	}
-
-	sig, err := sk.SignFile(fn)
-	if err != nil {
-		die("%s", err)
-	}
-
-	sigo, err := sig.Serialize(fmt.Sprintf("input=%s", fn))
-
-	var fd io.Writer = os.Stdout
-
-	if outf != "-" {
-		fdx, err := os.OpenFile(outf, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
-		if err != nil {
-			die("can't create output file %s: %s", outf, err)
-		}
-		defer fdx.Close()
-		fd = fdx
-	}
-
-	fd.Write(sigo)
-}
-
-// Verify signature on a given file
-func verify(args []string) {
-	var help, quiet bool
-
-	fs := flag.NewFlagSet("verify", flag.ExitOnError)
-	fs.BoolVarP(&help, "help", "h", false, "Show this help and exit")
-	fs.BoolVarP(&quiet, "quiet", "q", false, "Don't show any output; exit with status code only")
-
-	fs.Parse(args)
-
-	if help {
-		fs.SetOutput(os.Stdout)
-		fmt.Printf(`%s verify|v [options] pubkey sig file
-
-Verify an Ed25519 signature in SIG of FILE using a public key PUBKEY.
-
-Options:
-`, Z)
-		fs.PrintDefaults()
-		os.Exit(0)
-	}
-
-	args = fs.Args()
-	if len(args) < 3 {
-		die("Insufficient arguments to 'verify'. Try '%s verify -h' ..", Z)
-	}
-
-	pn := args[0]
-	sn := args[1]
-	fn := args[2]
-
-	sig, err := sign.ReadSignature(sn)
-	if err != nil {
-		die("Can't read signature '%s': %s", sn, err)
-	}
-
-	pk, err := sign.ReadPublicKey(pn)
-	if err != nil {
-		die("%s", err)
-	}
-
-	if !sig.IsPKMatch(pk) {
-		die("Wrong public key '%s' for verifying '%s'", pn, sn)
-	}
-
-	ok, err := pk.VerifyFile(fn, sig)
-	if err != nil {
-		die("%s", err)
-	}
-
-	exit := 0
-	if !ok {
-		exit = 1
-	}
-
-	if !quiet {
-		if ok {
-			fmt.Printf("%s: Signature %s verified\n", fn, sn)
-		} else {
-			fmt.Printf("%s: Signature %s verification failure\n", fn, sn)
-		}
-	}
-
-	os.Exit(exit)
-}
-
-func usage(c int) {
-	x := fmt.Sprintf(`%s is a tool to generate, sign and verify files with Ed25519 signatures.
-
-Usage: %s [global-options] command [options] arg [args..]
-
-Global options:
-  -h, --help       Show help and exit
-  -v, --version    Show version info and exit.
-
-Commands:
-  generate, g      Generate a new Ed25519 keypair
-  sign, s          Sign a file with a private key
-  verify, v        Verify a signature against a file and a public key
-  encrypt, e       Encrypt an input file to one or more recipients
-  decrypt, d       Decrypt a file with a private key
-`, Z, Z)
-
-	os.Stdout.Write([]byte(x))
-	os.Exit(c)
-}
-
-// Return true if $bn.key or $bn.pub exist; false otherwise
-func exists(bn string) bool {
-	pk := bn + ".pub"
-	sk := bn + ".key"
-
-	if _, err := os.Stat(pk); err == nil {
-		return true
-	}
-	if _, err := os.Stat(sk); err == nil {
-		return true
-	}
-
-	return false
-}
-
-// die with error
-func die(f string, v ...interface{}) {
-	warn(f, v...)
-	os.Exit(1)
-}
-
-func warn(f string, v ...interface{}) {
-	z := fmt.Sprintf("%s: %s", os.Args[0], f)
-	s := fmt.Sprintf(z, v...)
-	if n := len(s); s[n-1] != '\n' {
-		s += "\n"
-	}
-
-	os.Stderr.WriteString(s)
-	os.Stderr.Sync()
-}
-
-// This will be filled in by "build"
-var RepoVersion string = "UNDEFINED"
-var Buildtime string = "UNDEFINED"
-var ProductVersion string = "UNDEFINED"
-
-// vim: ft=go:sw=8:ts=8:noexpandtab:tw=98:

src/crypt.go

@@ -20,9 +20,10 @@ import (
 	"os"
 	"strings"
 
+	"git.rgst.io/homelab/sigtool/v3/sign"
+	"github.com/opencoff/go-fio"
 	"github.com/opencoff/go-utils"
 	flag "github.com/opencoff/pflag"
-	"github.com/opencoff/sigtool/sign"
 )
 
 // sigtool encrypt [-i|--identity my.key] to.pub [to.pub] [ssh.pub] inputfile|- [-o output]
@@ -35,19 +36,25 @@ func encrypt(args []string) {
 
 	var outfile string
 	var keyfile string
+	var szstr string = "128k"
 	var envpw string
-	var nopw bool
+	var nopw, force bool
 	var blksize uint64
 
 	fs.StringVarP(&outfile, "outfile", "o", "", "Write the output to file `F`")
 	fs.StringVarP(&keyfile, "sign", "s", "", "Sign using private key `S`")
 	fs.BoolVarP(&nopw, "no-password", "", false, "Don't ask for passphrase to decrypt the private key")
-	fs.StringVarP(&envpw, "env-password", "", "", "Use passphrase from environment variable `E`")
+	fs.StringVarP(&envpw, "env-password", "E", "", "Use passphrase from environment variable `E`")
-	fs.SizeVarP(&blksize, "block-size", "B", 128*1024, "Use `S` as the encryption block size")
+	fs.StringVarP(&szstr, "block-size", "B", szstr, "Use `S` as the encryption block size")
+	fs.BoolVarP(&force, "overwrite", "", false, "Overwrite the output file if it exists")
 
 	err := fs.Parse(args)
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
+	}
+
+	if blksize, err = utils.ParseSize(szstr); err != nil {
+		Die("%s", err)
 	}
 
 	var pws, infile string
@@ -63,19 +70,19 @@ func encrypt(args []string) {
 			} else {
 				pws, err = utils.Askpass("Enter passphrase for private key", false)
 				if err != nil {
-					die("%s", err)
+					Die("%s", err)
 				}
 			}
 			return []byte(pws), nil
 		})
 		if err != nil {
-			die("%s", err)
+			Die("%s", err)
 		}
 	}
 
 	args = fs.Args()
 	if len(args) < 2 {
-		die("Insufficient args. Try '%s --help'", os.Args[0])
+		Die("Insufficient args. Try '%s --help'", os.Args[0])
 	}
 
 	var infd io.Reader = os.Stdin
@@ -95,14 +102,14 @@ func encrypt(args []string) {
 	// Lets try to read the authorized files
 	home, err := os.UserHomeDir()
 	if err != nil {
-		die("can't find homedir for this user")
+		Die("can't find homedir for this user")
 	}
 
 	authkeys := fmt.Sprintf("%s/.ssh/authorized_keys", home)
 	authdata, err := ioutil.ReadFile(authkeys)
 	if err != nil {
-		if err != os.ErrNotExist {
+		if !os.IsNotExist(err) {
-			die("can't open %s: %s", authkeys, err)
+			Die("can't open %s: %s", authkeys, err)
 		}
 	}
 
@@ -114,31 +121,43 @@ func encrypt(args []string) {
 	}
 
 	if len(outfile) > 0 && outfile != "-" {
+		var mode os.FileMode = 0600 // conservative output mode
+
 		if inf != nil {
-			ost, err := os.Stat(outfile)
+			var err error
-			if err != nil {
+			var ist, ost os.FileInfo
-				die("can't stat %s: %s", outfile, err)
+
+			if ost, err = os.Stat(outfile); err != nil {
+				Die("can't stat %s: %s", outfile, err)
 			}
 
-			ist, err := inf.Stat()
+			if ist, err = inf.Stat(); err != nil {
-			if err != nil {
+				Die("can't stat %s: %s", infile, err)
-				die("can't stat %s: %s", infile, err)
 			}
 
 			if os.SameFile(ist, ost) {
-				die("won't create output file: same as input file!")
+				Die("won't create output file: same as input file!")
 			}
+			mode = ist.Mode()
 		}
 
-		outf := mustOpen(outfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC)
+		var opts uint32
-		defer outf.Close()
+		if force {
+			opts |= fio.OPT_OVERWRITE
+		}
+		sf, err := fio.NewSafeFile(outfile, opts, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, mode)
+		if err != nil {
+			Die("%s", err)
+		}
 
-		outfd = outf
+		AtExit(sf.Abort)
+		defer sf.Abort()
+		outfd = sf
 	}
 
 	en, err := sign.NewEncryptor(sk, blksize)
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
 	}
 
 	errs := 0
@@ -151,14 +170,14 @@ func encrypt(args []string) {
 			var ok bool
 			pk, ok = keymap[fn]
 			if !ok {
-				warn("can't find user %s in %s", fn, authkeys)
+				Warn("can't find user %s in %s", fn, authkeys)
 				errs += 1
 				continue
 			}
 		} else {
 			pk, err = sign.ReadPublicKey(fn)
 			if err != nil {
-				warn("%s", err)
+				Warn("%s", err)
 				errs += 1
 				continue
 			}
@@ -166,18 +185,19 @@ func encrypt(args []string) {
 
 		err = en.AddRecipient(pk)
 		if err != nil {
-			die("%s", err)
+			Die("%s", err)
 		}
 	}
 
 	if errs > 0 {
-		die("Too many errors!")
+		Die("Too many errors!")
 	}
 
 	err = en.Encrypt(infd, outfd)
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
 	}
+	outfd.Close()
 }
 
 type nullWriter struct{}
@@ -202,26 +222,27 @@ func decrypt(args []string) {
 	var envpw string
 	var outfile string
 	var pubkey string
-	var nopw, test bool
+	var nopw, test, force bool
 
 	fs.StringVarP(&outfile, "outfile", "o", "", "Write the output to file `F`")
 	fs.BoolVarP(&nopw, "no-password", "", false, "Don't ask for passphrase to decrypt the private key")
-	fs.StringVarP(&envpw, "env-password", "", "", "Use passphrase from environment variable `E`")
+	fs.StringVarP(&envpw, "env-password", "E", "", "Use passphrase from environment variable `E`")
 	fs.StringVarP(&pubkey, "verify-sender", "v", "", "Verify that the sender matches public key in `F`")
 	fs.BoolVarP(&test, "test", "t", false, "Test the encrypted file against the given key without writing to output")
+	fs.BoolVarP(&force, "overwrite", "", false, "Overwrite the output file if it exists")
 
 	err := fs.Parse(args)
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
 	}
 
 	args = fs.Args()
 	if len(args) < 1 {
-		die("Insufficient args. Try '%s --help'", os.Args[0])
+		Die("Insufficient args. Try '%s --help'", os.Args[0])
 	}
 
 	var infd io.Reader = os.Stdin
-	var outfd io.Writer = os.Stdout
+	var outfd io.WriteCloser = os.Stdout
 	var inf *os.File
 	var infile string
 
@@ -237,13 +258,13 @@ func decrypt(args []string) {
 		} else {
 			pws, err = utils.Askpass("Enter passphrase for private key", false)
 			if err != nil {
-				die("%s", err)
+				Die("%s", err)
 			}
 		}
 		return []byte(pws), nil
 	})
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
 	}
 
 	var pk *sign.PublicKey
@@ -251,7 +272,7 @@ func decrypt(args []string) {
 	if len(pubkey) > 0 {
 		pk, err = sign.ReadPublicKey(pubkey)
 		if err != nil {
-			die("%s", err)
+			Die("%s", err)
 		}
 	}
 
@@ -268,34 +289,46 @@ func decrypt(args []string) {
 	if test {
 		outfd = &nullWriter{}
 	} else if len(outfile) > 0 && outfile != "-" {
+		var mode os.FileMode = 0600 // conservative mode
+
 		if inf != nil {
-			ost, err := os.Stat(outfile)
+			var ist, ost os.FileInfo
-			if err != nil {
+			var err error
-				die("can't stat %s: %s", outfile, err)
+
+			if ost, err = os.Stat(outfile); err != nil {
+				Die("can't stat %s: %s", outfile, err)
 			}
-			ist, err := inf.Stat()
+			if ist, err = inf.Stat(); err != nil {
-			if err != nil {
+				Die("can't stat %s: %s", infile, err)
-				die("can't stat %s: %s", infile, err)
 			}
 			if os.SameFile(ist, ost) {
-				die("won't create output file: same as input file!")
+				Die("won't create output file: same as input file!")
 			}
+			mode = ist.Mode()
 		}
 
-		outf := mustOpen(outfile, os.O_WRONLY|os.O_CREATE|os.O_TRUNC)
+		var opts uint32
-		defer outf.Close()
+		if force {
+			opts |= fio.OPT_OVERWRITE
+		}
+		sf, err := fio.NewSafeFile(outfile, opts, os.O_WRONLY|os.O_CREATE|os.O_TRUNC, mode)
+		if err != nil {
+			Die("%s", err)
+		}
 
-		outfd = outf
+		AtExit(sf.Abort)
+		defer sf.Abort()
+		outfd = sf
 	}
 
 	d, err := sign.NewDecryptor(infd)
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
 	}
 
 	err = d.SetPrivateKey(sk, pk)
 	if err != nil {
-		die("%s", err)
+		Die("%s", err)
 	}
 
 	if pk == nil && d.AuthenticatedSender() {
@@ -303,17 +336,19 @@ func decrypt(args []string) {
 		if len(fn) == 0 || fn == "-" {
 			fn = "<stdin>"
 		}
-		warn("%s: Missing sender Public Key; can't authenticate sender ..", fn)
+		Warn("%s: Missing sender Public Key; can't authenticate sender ..", fn)
 	}
 
-	err = d.Decrypt(outfd)
+	if err = d.Decrypt(outfd); err != nil {
-	if err != nil {
+		Die("%s", err)
-		die("%s", err)
 	}
 
+	outfd.Close()
+
 	if test {
-		warn("Enc file OK")
+		Warn("Enc file OK")
 	}
+
 }
 
 func encryptUsage(fs *flag.FlagSet) {
@@ -321,9 +356,16 @@ func encryptUsage(fs *flag.FlagSet) {
 
 Usage: %s encrypt [options] to [to ...] infile|-
 
-Where TO is the public key of the recipient and INFILE is an input file.
+Where TO is the public key of the recipient; it can be one of:
-If the input file is '-' then %s reads from STDIN. Unless '-o' is used,
+
-%s writes the encrypted output to STDOUT.
+- a file referring to an SSH or sigtool public key.
+- string of the form 'a@b' - in which case the user's default
+  ssh/authorized_keys is consulted to find the comment matching
+  'a@b' - in which case the user's ssh authorized_keys file is consulted to
+  find the comment matching the string.
+
+INFILE is an input file to be encrypted. If the input file is '-' then %s
+reads from STDIN. Unless '-o' is used, %s writes the encrypted output to STDOUT.
 
 Options:
 `, Z, Z, Z, Z)
@@ -351,7 +393,7 @@ Options:
 func mustOpen(fn string, flag int) *os.File {
 	fdk, err := os.OpenFile(fn, flag, 0600)
 	if err != nil {
-		die("can't open file %s: %s", fn, err)
+		Die("can't open file %s: %s", fn, err)
 	}
 	return fdk
 }

src/die.go

@@ -0,0 +1,55 @@
+// die.go -- die() and warn()
+//
+// (c) 2016 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package main
+
+import (
+	"fmt"
+	"os"
+)
+
+var atExit []func()
+
+// Die prints an error message to stderr
+// and exits the program after calling all the registered
+// at-exit functions.
+func Die(f string, v ...interface{}) {
+	Warn(f, v...)
+	Exit(1)
+}
+
+// Warn prints an error message to stderr
+func Warn(f string, v ...interface{}) {
+	z := fmt.Sprintf("%s: %s", os.Args[0], f)
+	s := fmt.Sprintf(z, v...)
+	if n := len(s); s[n-1] != '\n' {
+		s += "\n"
+	}
+
+	os.Stderr.WriteString(s)
+	os.Stderr.Sync()
+}
+
+// AtExit registers a function to be called before the program exits.
+func AtExit(f func()) {
+	atExit = append(atExit, f)
+}
+
+// Exit invokes the registered atexit handlers and exits with the
+// given code.
+func Exit(v int) {
+	for _, f := range atExit {
+		f()
+	}
+	os.Exit(v)
+}

src/gen.go

@@ -0,0 +1,100 @@
+// gen.go -- generate keys
+//
+// (c) 2016 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path"
+
+	"git.rgst.io/homelab/sigtool/v3/sign"
+	"github.com/opencoff/go-utils"
+	flag "github.com/opencoff/pflag"
+)
+
+// Run the generate command
+func gen(args []string) {
+	var nopw, help, force bool
+	var comment string
+	var envpw string
+
+	fs := flag.NewFlagSet("generate", flag.ExitOnError)
+	fs.BoolVarP(&help, "help", "h", false, "Show this help and exit")
+	fs.BoolVarP(&nopw, "no-password", "", false, "Don't ask for a password for the private key")
+	fs.StringVarP(&comment, "comment", "c", "", "Use `C` as the text comment for the keys")
+	fs.StringVarP(&envpw, "env-password", "E", "", "Use passphrase from environment variable `E`")
+	fs.BoolVarP(&force, "overwrite", "", false, "Overwrite the output file if it exists")
+
+	fs.Parse(args)
+
+	if help {
+		fs.SetOutput(os.Stdout)
+		fmt.Printf(`%s generate|gen|g [options] file-prefix
+
+Generate a new Ed25519 public+private key pair and write public key to
+FILE-PREFIX.pub and private key to FILE-PREFIX.key.
+
+Options:
+`, Z)
+		fs.PrintDefaults()
+		os.Exit(0)
+	}
+
+	args = fs.Args()
+	if len(args) < 1 {
+		Die("Insufficient arguments to 'generate'. Try '%s generate -h' ..", Z)
+	}
+
+	bn := args[0]
+
+	pkn := fmt.Sprintf("%s.pub", path.Clean(bn))
+	skn := fmt.Sprintf("%s.key", path.Clean(bn))
+
+	if !force {
+		if exists(pkn) || exists(skn) {
+			Die("Public/Private key files (%s, %s) exist. won't overwrite!", skn, pkn)
+		}
+	}
+
+	var err error
+	var pw []byte
+
+	if !nopw {
+		var pws string
+		if len(envpw) > 0 {
+			pws = os.Getenv(envpw)
+		} else {
+			pws, err = utils.Askpass("Enter passphrase for private key", true)
+			if err != nil {
+				Die("%s", err)
+			}
+		}
+
+		pw = []byte(pws)
+	}
+
+	sk, err := sign.NewPrivateKey()
+	if err != nil {
+		Die("%s", err)
+	}
+
+	if err = sk.Serialize(skn, comment, force, pw); err != nil {
+		Die("%s", err)
+	}
+
+	pk := sk.PublicKey()
+	if err = pk.Serialize(pkn, comment, force); err != nil {
+		Die("%s", err)
+	}
+}

src/sign.go

@@ -0,0 +1,116 @@
+// sign.go -- 'sign' command implementation
+//
+// (c) 2016 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package main
+
+import (
+	"fmt"
+	"io"
+	"os"
+
+	"git.rgst.io/homelab/sigtool/v3/sign"
+	"github.com/opencoff/go-fio"
+	"github.com/opencoff/go-utils"
+	flag "github.com/opencoff/pflag"
+)
+
+// Run the 'sign' command.
+func signify(args []string) {
+	var nopw, help, force bool
+	var output string
+	var envpw string
+
+	fs := flag.NewFlagSet("sign", flag.ExitOnError)
+	fs.BoolVarP(&help, "help", "h", false, "Show this help and exit")
+	fs.BoolVarP(&nopw, "no-password", "", false, "Don't ask for a password for the private key")
+	fs.StringVarP(&envpw, "env-password", "E", "", "Use passphrase from environment variable `E`")
+	fs.StringVarP(&output, "output", "o", "", "Write signature to file `F`")
+	fs.BoolVarP(&force, "overwrite", "", false, "Overwrite previous signature file if it exists")
+
+	fs.Parse(args)
+
+	if help {
+		fs.SetOutput(os.Stdout)
+		fmt.Printf(`%s sign|s [options] privkey file
+
+Sign FILE with a Ed25519 private key PRIVKEY and write signature to FILE.sig
+
+Options:
+`, Z)
+		fs.PrintDefaults()
+		os.Exit(0)
+	}
+
+	args = fs.Args()
+	if len(args) < 2 {
+		Die("Insufficient arguments to 'sign'. Try '%s sign -h' ..", Z)
+	}
+
+	kn := args[0]
+	fn := args[1]
+	outf := fmt.Sprintf("%s.sig", fn)
+
+	var err error
+
+	if len(output) > 0 {
+		outf = output
+	}
+
+	var fd io.WriteCloser = os.Stdout
+
+	if outf != "-" {
+		var opts uint32
+		if force {
+			opts |= fio.OPT_OVERWRITE
+		}
+		sf, err := fio.NewSafeFile(outf, opts, os.O_CREATE|os.O_TRUNC|os.O_WRONLY, 0644)
+		if err != nil {
+			Die("can't create sig file: %s", err)
+		}
+
+		// we unlink and remove temp on any error
+		AtExit(sf.Abort)
+		defer sf.Abort()
+		fd = sf
+	}
+
+	sk, err := sign.ReadPrivateKey(kn, func() ([]byte, error) {
+		if nopw {
+			return nil, nil
+		}
+
+		var pws string
+		if len(envpw) > 0 {
+			pws = os.Getenv(envpw)
+		} else {
+			pws, err = utils.Askpass("Enter passphrase for private key", false)
+			if err != nil {
+				Die("%s", err)
+			}
+		}
+
+		return []byte(pws), nil
+	})
+	if err != nil {
+		Die("%s", err)
+	}
+
+	sig, err := sk.SignFile(fn)
+	if err != nil {
+		Die("%s", err)
+	}
+
+	sigbytes, err := sig.MarshalBinary(fmt.Sprintf("input=%s", fn))
+	fd.Write(sigbytes)
+	fd.Close()
+}

src/sigtool.go

@@ -0,0 +1,129 @@
+// sigtool.go -- Tool to generate, manage Ed25519 keys and
+// signatures.
+//
+// (c) 2016 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package main
+
+import (
+	"fmt"
+	"os"
+	"path"
+	"strings"
+
+	"git.rgst.io/homelab/sigtool/v3/sign"
+	"github.com/opencoff/go-utils"
+	flag "github.com/opencoff/pflag"
+)
+
+var Z string = path.Base(os.Args[0])
+
+func main() {
+	var ver, help, debug bool
+
+	mf := flag.NewFlagSet(Z, flag.ExitOnError)
+	mf.SetInterspersed(false)
+	mf.BoolVarP(&ver, "version", "v", false, "Show version info and exit")
+	mf.BoolVarP(&help, "help", "h", false, "Show help info exit")
+	mf.BoolVarP(&debug, "debug", "", false, "Enable debug mode")
+	mf.Parse(os.Args[1:])
+
+	if ver {
+		fmt.Printf("%s - %s [%s]\n", Z, ProductVersion, RepoVersion)
+		os.Exit(0)
+	}
+
+	if help {
+		usage(0)
+	}
+
+	args := mf.Args()
+	if len(args) < 1 {
+		Die("Insufficient arguments. Try '%s -h'", Z)
+	}
+
+	cmds := map[string]func(args []string){
+		"generate": gen,
+		"sign":     signify,
+		"verify":   verify,
+		"encrypt":  encrypt,
+		"decrypt":  decrypt,
+
+		"help": func(_ []string) {
+			usage(0)
+		},
+	}
+
+	words := make([]string, 0, len(cmds))
+	for k := range cmds {
+		words = append(words, k)
+	}
+
+	ab := utils.Abbrev(words)
+	canon, ok := ab[strings.ToLower(args[0])]
+	if !ok {
+		Die("Unknown command %s", args[0])
+	}
+
+	cmd := cmds[canon]
+	if cmd == nil {
+		Die("can't map command %s", canon)
+	}
+
+	if debug {
+		sign.Debug(1)
+	}
+
+	cmd(args[1:])
+
+	// always call Exit so that at-exit handlers are called.
+	Exit(0)
+}
+
+// Verify signature on a given file
+
+func usage(c int) {
+	x := fmt.Sprintf(`%s is a tool to generate, sign and verify files with Ed25519 signatures.
+
+Usage: %s [global-options] command [options] arg [args..]
+
+Global options:
+  -h, --help       Show help and exit
+  -v, --version    Show version info and exit
+  --debug	   Enable debug (DANGEROUS)
+
+Commands:
+  generate, g      Generate a new Ed25519 keypair
+  sign, s          Sign a file with a private key
+  verify, v        Verify a signature against a file and a public key
+  encrypt, e       Encrypt an input file to one or more recipients
+  decrypt, d       Decrypt a file with a private key
+`, Z, Z)
+
+	os.Stdout.Write([]byte(x))
+	os.Exit(c)
+}
+
+// Return true if $bn.key or $bn.pub exist; false otherwise
+func exists(nm string) bool {
+	if _, err := os.Stat(nm); err == nil {
+		return true
+	}
+
+	return false
+}
+
+// This will be filled in by "build"
+var RepoVersion string = "UNDEFINED"
+var ProductVersion string = "UNDEFINED"
+
+// vim: ft=go:sw=8:ts=8:noexpandtab:tw=98:

src/verify.go

@@ -0,0 +1,96 @@
+// verify.go -- Verify signatures
+//
+// (c) 2016 Sudhi Herle <sudhi@herle.net>
+//
+// Licensing Terms: GPLv2
+//
+// If you need a commercial license for this work, please contact
+// the author.
+//
+// This software does not come with any express or implied
+// warranty; it is provided "as is". No claim  is made to its
+// suitability for any purpose.
+
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"git.rgst.io/homelab/sigtool/v3/sign"
+	flag "github.com/opencoff/pflag"
+)
+
+func verify(args []string) {
+	var help, quiet bool
+
+	fs := flag.NewFlagSet("verify", flag.ExitOnError)
+	fs.BoolVarP(&help, "help", "h", false, "Show this help and exit")
+	fs.BoolVarP(&quiet, "quiet", "q", false, "Don't show any output; exit with status code only")
+
+	fs.Parse(args)
+
+	if help {
+		fs.SetOutput(os.Stdout)
+		fmt.Printf(`%s verify|v [options] pubkey sig file
+
+Verify an Ed25519 signature in SIG of FILE using a public key PUBKEY.
+The pubkey can be one of:
+  - a file: either OpenSSH ed25519 pubkey or a sigtool pubkey
+  - a string: the raw OpenSSH or sigtool pubkey
+
+%s will first parse it as a string before trying to parse it as a file.
+
+Options:
+`, Z, Z)
+		fs.PrintDefaults()
+		os.Exit(0)
+	}
+
+	args = fs.Args()
+	if len(args) < 3 {
+		Die("Insufficient arguments to 'verify'. Try '%s verify -h' ..", Z)
+	}
+
+	pn := args[0]
+	sn := args[1]
+	fn := args[2]
+
+	// We first try to read the public key as a base64/openssh string
+	pk, err := sign.MakePublicKeyFromString(pn)
+	if err != nil {
+		pk, err = sign.ReadPublicKey(pn)
+		if err != nil {
+			Die("%s", err)
+		}
+	}
+
+	sig, err := sign.ReadSignature(sn)
+	if err != nil {
+		Die("Can't read signature '%s': %s", sn, err)
+	}
+
+	if !sig.IsPKMatch(pk) {
+		Die("Wrong public key '%s' for verifying '%s'", pn, sn)
+	}
+
+	ok, err := pk.VerifyFile(fn, sig)
+	if err != nil {
+		Die("%s", err)
+	}
+
+	exit := 0
+	if !ok {
+		exit = 1
+	}
+
+	if !quiet {
+		if ok {
+			fmt.Printf("%s: Signature %s verified\n", fn, sn)
+		} else {
+			fmt.Printf("%s: Signature %s verification failure\n", fn, sn)
+		}
+	}
+
+	os.Exit(exit)
+}

tests.sh

@@ -0,0 +1,124 @@
+#! /usr/bin/env bash
+# simple round-trip tests to verify the tool
+# Usage:
+#    $0 [bin=/path/to/sigtool] [tmpdir=/path/to/workdir]
+
+Z=`basename $0`
+die() {
+    echo "$Z: $@" 1>&2
+    echo "$Z: Test output in $tmpdir .." 1>&2
+    exit 1
+}
+
+# cmd line args processing
+for a in $*; do
+    key=${a%=*}
+    val=${a#*=}
+    case $key in
+        bin)
+            bin=$val
+            ;;
+
+        tmpdir)
+            tmpdir=$val
+            ;;
+
+        *)
+            echo "Ignoring $key .."
+            ;;
+    esac
+done
+
+if [ -z "$bin" ]; then
+    arch=`./build --print-arch`
+    bin=./bin/$arch/sigtool
+
+    [ -x $bin ] || ./build || die "can't find & build sigtool"
+fi
+
+[ -z "$tmpdir" ] && tmpdir=/tmp/sigtool$$
+
+mkdir -p $tmpdir        || die "can't mkdir $tmpdir"
+
+# env name for reading the password
+passenv=FOO
+
+# this is the password for SKs
+FOO=bar
+
+
+#trap "rm -rf $tmpdir" EXIT
+
+bn=$tmpdir/foo
+sig=$tmpdir/$Z.sig
+pk=$bn.pub
+sk=$bn.key
+bn2=$tmpdir/bar
+pk2=$bn2.pub
+sk2=$bn2.key
+
+encout=$tmpdir/$Z.enc
+decout=$tmpdir/$Z.dec
+
+# exit on any failure
+set -e
+
+# Now try with ssh ed25519 keys
+keygen=`which ssh-keygen`
+[ -z "$keygen" ] && die "can't find ssh-keygen"
+
+ssk1=$tmpdir/ssk1
+spk1=$ssk1.pub
+
+ssk2=$tmpdir/ssk2
+spk2=$ssk2.pub
+
+# first generate two ssh keys
+$keygen -q -C 'ssk1@foo' -t ed25519 -f $ssk1 -N "" 
+$keygen -q -C 'ssk2@foo' -t ed25519 -f $ssk2 -N "" 
+
+# extract the pk string
+spk1_str=$(cat $spk1 | awk '{ print $2 }')
+
+$bin s --no-password $ssk1 -o $sig $0       || die "can't sign with $ssk1"
+$bin v -q $spk1 $sig $0                     || die "can't verify with $spk2"
+$bin v -q $spk1_str $sig $0                 || die "can't verify with $spk2_str"
+
+$bin e --no-password -o $encout $spk2 $0       || die "can't encrypt to $spk2 with $ssk1"
+$bin d --no-password -o $decout $ssk2 $encout  || die "can't decrypt with $ssk2"
+
+# cleanup state
+rm -f $sig $encout $decout
+
+# generate keys
+$bin g -E FOO $bn                || die "can't gen keypair $pk, $sk"
+$bin g -E FOO $bn 2>/dev/null    && die "overwrote prev keypair"
+$bin g -E FOO --overwrite $bn    || die "can't force gen keypair $pk, $sk"
+$bin g -E FOO $bn2               || die "can't force gen keypair $pk2, $sk2"
+
+# extract pk string
+pk_str=$(cat $pk | grep 'pk:' | sed -e 's/^pk: //g')
+pk2_str=$(cat $pk2 | grep 'pk:' | sed -e 's/^pk: //g')
+
+# sign and verify
+$bin s -E FOO $sk $0 -o $sig            || die "can't sign $0"
+$bin v -q $pk $sig $0                   || die "can't verify signature of $0"
+$bin v -q $pk_str $sig $0               || die "can't verify signature of $0"
+$bin v -q $pk2 $sig $0 2>/dev/null      && die "bad verification with wrong $pk2"
+$bin v -q $pk2_str $sig $0 2>/dev/null  && die "bad verification with wrong $pk2"
+
+# encrypt/decrypt
+$bin e -E FOO -o $encout $pk2 $0      || die "can't encrypt to $pk2"
+$bin d -E FOO -o $decout $sk2 $encout || die "can't decrypt with $sk2"
+cmp -s $decout $0                     || die "decrypted file mismatch with $0"
+
+# now with sender verification
+$bin e -E FOO --overwrite -o $encout -s $sk $pk2 $0      || die "can't sender-encrypt to $pk2"
+$bin d -E FOO --overwrite -o $decout -v $pk $sk2 $encout || die "can't decrypt with $sk2"
+cmp -s $decout $0                                        || die "decrypted file mismatch with $0"
+
+# Only delete if everything worked
+echo "$Z: All tests pass!"
+rm -rf $tmpdir
+
+# vim: tw=100 sw=4 ts=4 expandtab