// getAntiTag returns a digest for the entire header stack. It needs to be run
// before a new header is inserted but after deterministic headers are appended
// to the bottom of the header stack.
func (m *encMessage) getAntiTag() []byte {
digest, err := blake2s.New(nil)
if err != nil {
panic(err)
}
digest.Write(m.payload[headerBytes:])
return digest.Sum(nil)
}
// makeKeyID generates a 16 Byte KeyID based on the hash of a Public Key
func makeKeyID(pub []byte) []byte {
digest, err := blake2s.New(&blake2s.Config{Size: 16})
if err != nil {
panic(err)
}
digest.Write(pub)
return digest.Sum(nil)
}
// testAntiTag creates a Blake2 hash of the entire payload (less the top
// headerBytes) and compares it with the provided hash. If the two collide, it
// returns True.
func (m *decMessage) testAntiTag(tag []byte) bool {
digest, err := blake2s.New(nil)
if err != nil {
panic(err)
}
digest.Write(m.payload[headerBytes:])
if bytes.Compare(tag, digest.Sum(nil)) == 0 {
return true
}
return false
}
// Generate 1-byte checksum using blake2s.
func (ks *Keys) checksum() ([]byte, error) {
var written int
blakeHasher, err := blake2s.New(&blake2s.Config{Size: 1})
if err != nil {
return nil, err
}
written, err = blakeHasher.Write(ks.Public)
if err != nil {
return nil, err
}
if written != 32 {
return nil, ErrChecksumFail
}
checksum := blakeHasher.Sum(nil)
if len(checksum) != 1 {
return nil, ErrChecksumFail
}
return checksum, nil
}
// Generate 1-byte checksum using blake2s.
func (self *Keys) checksum() ([]byte, error) {
var written int
blakeHasher, err := blake2s.New(&blake2s.Config{Size: 1})
if err != nil {
return nil, err
}
written, err = blakeHasher.Write(self.Public)
if err != nil {
return nil, err
}
if written != 32 {
return nil, ChecksumGenerationError
}
checksum := blakeHasher.Sum(nil)
if len(checksum) != 1 {
return nil, ChecksumGenerationError
}
return checksum, nil
}
type hashDesc struct {
name string
maxSize int
maker func(size uint8) (hash.Hash, error)
}
var algorithms = map[string]hashDesc{
"blake2b": {
"BLAKE2b",
blake2b.Size,
func(size uint8) (hash.Hash, error) { return blake2b.New(&blake2b.Config{Size: size}) },
},
"blake2s": {
"BLAKE2s",
blake2s.Size,
func(size uint8) (hash.Hash, error) { return blake2s.New(&blake2s.Config{Size: size}) },
},
}
func calcSum(f *os.File, h hash.Hash) (sum []byte, err error) {
h.Reset()
_, err = io.Copy(h, f)
sum = h.Sum(nil)
return
}
func main() {
flag.Parse()
algo, ok := algorithms[*algoFlag]
if !ok {
