// package PKG:
//
// PKG = P1 || P2
-// P1 = Salsa20(key=r, nonce=0x00, 0x00) XOR (M || BLAKE2b(r || M))
+// P1 = ChaCha20(key=r, nonce=0x00, 0x00) XOR (M || BLAKE2b(r || M))
// P2 = BLAKE2b(P1) XOR r
package aont
"crypto/subtle"
"errors"
+ "chacha20"
"golang.org/x/crypto/blake2b"
- "golang.org/x/crypto/salsa20"
)
const (
)
var (
- dummyNonce []byte = make([]byte, 8)
+ dummyNonce *[16]byte = new([16]byte)
)
// Encode the data, produce AONT package. Data size will be larger than
h.Write(r[:])
h.Write(in)
copy(out[len(in):], h.Sum(nil))
- salsaKey := new([32]byte)
- copy(salsaKey[:], r[:])
- salsa20.XORKeyStream(out, out, dummyNonce, salsaKey)
+ chachaKey := new([32]byte)
+ copy(chachaKey[:], r[:])
+ chacha20.XORKeyStream(out, out, dummyNonce, chachaKey)
h.Reset()
h.Write(out[:len(in)+32])
for i, b := range h.Sum(nil)[:RSize] {
return nil, err
}
h.Write(in[:len(in)-RSize])
- salsaKey := new([32]byte)
+ chachaKey := new([32]byte)
for i, b := range h.Sum(nil)[:RSize] {
- salsaKey[i] = b ^ in[len(in)-RSize+i]
+ chachaKey[i] = b ^ in[len(in)-RSize+i]
}
h.Reset()
- h.Write(salsaKey[:RSize])
+ h.Write(chachaKey[:RSize])
out := make([]byte, len(in)-RSize)
- salsa20.XORKeyStream(out, in[:len(in)-RSize], dummyNonce, salsaKey)
+ chacha20.XORKeyStream(out, in[:len(in)-RSize], dummyNonce, chachaKey)
h.Write(out[:len(out)-HSize])
if subtle.ConstantTimeCompare(h.Sum(nil), out[len(out)-HSize:]) != 1 {
return nil, errors.New("Invalid checksum")