sigtool/sign/encrypt_test.go
Sudhi Herle 00542dec02 Major breaking changes: Reworked file encryption scheme
* all encryption now uses ephmeral curve25519 keys
* sender can identify themselves by providing a signing key
* sign/verify now uses a string prefix for calculating checksum of the
  incoming message + known prefix [prevents us from verifying unknown
  blobs]
* encrypt/decrypt key is now expanded with a known prefix _and_ the
  header checksum
* protobuf definition changed to include an encrypted sender
  identification blob (sender public key)
* moved protobuf files into an internal/pb directory
* general code rearrangement to make it easy to find files
* added extra validation for reading all keys
* bumped version to 1.0.0
2020-03-20 17:40:52 -07:00

331 lines
7.7 KiB
Go

// crypt_test.go -- Test harness for encrypt/decrypt bits
//
// (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 (
"bytes"
"crypto/rand"
"encoding/binary"
"fmt"
"io"
"testing"
)
type Buffer struct {
bytes.Buffer
}
func (b *Buffer) Close() error {
return nil
}
// one sender, one receiver no verification of sender
func TestEncryptSimple(t *testing.T) {
assert := newAsserter(t)
receiver, err := NewKeypair()
assert(err == nil, "receiver keypair gen failed: %s", err)
var blkSize int = 1024
var size int = (blkSize * 10)
// cleartext
buf := make([]byte, size)
for i := 0; i < len(buf); i++ {
buf[i] = byte(i & 0xff)
}
ee, err := NewEncryptor(nil, uint64(blkSize))
assert(err == nil, "encryptor create fail: %s", err)
err = ee.AddRecipient(&receiver.Pub)
assert(err == nil, "can't add recipient: %s", err)
rd := bytes.NewBuffer(buf)
wr := Buffer{}
err = ee.Encrypt(rd, &wr)
assert(err == nil, "encrypt fail: %s", err)
rd = bytes.NewBuffer(wr.Bytes())
dd, err := NewDecryptor(rd)
assert(err == nil, "decryptor create fail: %s", err)
err = dd.SetPrivateKey(&receiver.Sec, nil)
assert(err == nil, "decryptor can't add SK: %s", err)
wr = Buffer{}
err = dd.Decrypt(&wr)
assert(err == nil, "decrypt fail: %s", err)
b := wr.Bytes()
assert(len(b) == len(buf), "decrypt length mismatch: exp %d, saw %d", len(buf), len(b))
assert(byteEq(b, buf), "decrypt content mismatch")
}
// test corrupted header or corrupted input
func TestEncryptCorrupted(t *testing.T) {
assert := newAsserter(t)
receiver, err := NewKeypair()
assert(err == nil, "receiver keypair gen failed: %s", err)
var blkSize int = 1024
var size int = (blkSize * 23) + randmod(blkSize)
// cleartext
buf := make([]byte, size)
for i := 0; i < len(buf); i++ {
buf[i] = byte(i & 0xff)
}
ee, err := NewEncryptor(nil, uint64(blkSize))
assert(err == nil, "encryptor create fail: %s", err)
err = ee.AddRecipient(&receiver.Pub)
assert(err == nil, "can't add recipient: %s", err)
rd := bytes.NewReader(buf)
wr := Buffer{}
err = ee.Encrypt(rd, &wr)
assert(err == nil, "encrypt fail: %s", err)
rb := wr.Bytes()
n := len(rb)
for i := 0; i < n; i++ {
j := randint() % n
rb[j] = byte(randint() & 0xff)
}
rd = bytes.NewReader(rb)
dd, err := NewDecryptor(rd)
assert(err != nil, "decryptor works on bad input")
assert(dd == nil, "decryptor not nil for bad input")
}
// one sender, one receiver with verification of sender
func TestEncryptSenderVerified(t *testing.T) {
assert := newAsserter(t)
sender, err := NewKeypair()
assert(err == nil, "sender keypair gen failed: %s", err)
receiver, err := NewKeypair()
assert(err == nil, "receiver keypair gen failed: %s", err)
var blkSize int = 1024
var size int = (blkSize * 23) + randmod(blkSize)
// cleartext
buf := make([]byte, size)
for i := 0; i < len(buf); i++ {
buf[i] = byte(i & 0xff)
}
ee, err := NewEncryptor(&sender.Sec, uint64(blkSize))
assert(err == nil, "encryptor create fail: %s", err)
err = ee.AddRecipient(&receiver.Pub)
assert(err == nil, "can't add recipient: %s", err)
rd := bytes.NewBuffer(buf)
wr := Buffer{}
err = ee.Encrypt(rd, &wr)
assert(err == nil, "encrypt fail: %s", err)
rd = bytes.NewBuffer(wr.Bytes())
dd, err := NewDecryptor(rd)
assert(err == nil, "decryptor create fail: %s", err)
// first send a wrong sender key
randkey, err := NewKeypair()
assert(err == nil, "receiver rand keypair gen failed: %s", err)
err = dd.SetPrivateKey(&receiver.Sec, &randkey.Pub)
assert(err != nil, "decryptor failed to verify sender")
err = dd.SetPrivateKey(&receiver.Sec, &sender.Pub)
assert(err == nil, "decryptor can't add SK: %s", err)
wr = Buffer{}
err = dd.Decrypt(&wr)
assert(err == nil, "decrypt fail: %s", err)
b := wr.Bytes()
assert(len(b) == len(buf), "decrypt length mismatch: exp %d, saw %d", len(buf), len(b))
assert(byteEq(b, buf), "decrypt content mismatch")
}
// one sender, multiple receivers, each decrypting the blob
func TestEncryptMultiReceiver(t *testing.T) {
assert := newAsserter(t)
sender, err := NewKeypair()
assert(err == nil, "sender keypair gen failed: %s", err)
var blkSize int = 1024
var size int = (blkSize * 23) + randmod(blkSize)
// cleartext
buf := make([]byte, size)
for i := 0; i < len(buf); i++ {
buf[i] = byte(i & 0xff)
}
ee, err := NewEncryptor(&sender.Sec, uint64(blkSize))
assert(err == nil, "encryptor create fail: %s", err)
n := 4
rx := make([]*Keypair, n)
for i := 0; i < n; i++ {
r, err := NewKeypair()
assert(err == nil, "can't make receiver key %d: %s", i, err)
rx[i] = r
err = ee.AddRecipient(&r.Pub)
assert(err == nil, "can't add recipient %d: %s", i, err)
}
rd := bytes.NewBuffer(buf)
wr := Buffer{}
err = ee.Encrypt(rd, &wr)
assert(err == nil, "encrypt fail: %s", err)
encBytes := wr.Bytes()
for i := 0; i < n; i++ {
rd = bytes.NewBuffer(encBytes)
dd, err := NewDecryptor(rd)
assert(err == nil, "decryptor %d create fail: %s", i, err)
err = dd.SetPrivateKey(&rx[i].Sec, &sender.Pub)
assert(err == nil, "decryptor can't add SK %d: %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 stream write and read
func TestStreamIO(t *testing.T) {
assert := newAsserter(t)
receiver, err := NewKeypair()
assert(err == nil, "receiver keypair gen failed: %s", err)
var blkSize int = 1024
var size int = (blkSize * 10)
// cleartext
buf := make([]byte, size)
for i := 0; i < len(buf); i++ {
buf[i] = byte(i & 0xff)
}
ee, err := NewEncryptor(nil, uint64(blkSize))
assert(err == nil, "encryptor create fail: %s", err)
err = ee.AddRecipient(&receiver.Pub)
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 := 19
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.Sec, 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
_, err := io.ReadFull(rand.Reader, b[:])
if err != nil {
panic(fmt.Sprintf("can't read 4 rand bytes: %s", err))
}
u := binary.BigEndian.Uint32(b[:])
return int(u & 0x7fffffff)
}
func randmod(m int) int {
return randint() % m
}