Exemplo n.º 1
0
// Open authenticates and recovers the message secured in the box.
func Open(password, box []byte) (msg []byte, ok bool) {
	if len(box) < (secretbox.Overhead + 2*saltLength) {
		return
	}

	key, ok := recoverKey(password, box[:saltLength])
	if !ok {
		return
	}
	ok = false

	tag := keccakMac(key[:saltLength], box[:saltLength])
	if subtle.ConstantTimeCompare(tag, box[saltLength:2*saltLength]) != 1 {
		return
	}

	var sbKey [secretbox.KeySize]byte
	copy(sbKey[:], key[saltLength:])
	msg, ok = secretbox.Open(box[2*saltLength:], &sbKey)
	secretbox.Zero(sbKey[:])
	if !ok {
		msg = nil
		return
	}
	ok = true
	return
}
Exemplo n.º 2
0
// Open authenticates and recovers a message secured with public
// key cryptography.
func Open(box []byte, priv *[PrivateKeySize]byte) (msg []byte, ok bool) {
	if len(box) < (2 + PublicKeySize + secretbox.Overhead) {
		return
	} else if box[0] != BoxVersion {
		// Need to convert box to newer version!
		return
	} else if box[1] != TypeSingle {
		return
	} else if box[2] != CipherDualCurve25519 {
		return
	}
	var pub = new([PublicKeySize]byte)
	copy(pub[:], box[3:3+PublicKeySize])
	var sbox = make([]byte, len(box)-3-PublicKeySize)
	copy(sbox, box[3+PublicKeySize:])

	sk := SharedKey(priv, pub)
	return secretbox.Open(sbox, sk)
}
Exemplo n.º 3
0
// Decrypt authenticates and opens the message stored in a box.
func Decrypt(key *Key, box *Box) []byte {
	if key == nil || box == nil {
		return nil
	}

	sbkey := cekdf(key, box.Timestamp)
	defer zero(sbkey[:])

	var tagKey [k512Size]byte
	copy(tagKey[:], sbkey[k512Size:])
	defer zero(tagKey[:])

	tag := tagTimestamp(tagKey, box.Timestamp)
	if subtle.ConstantTimeCompare(tag, box.Tag) != 1 {
		return nil
	}

	msg, ok := secretbox.Open(box.Data, sbkey)
	if !ok {
		return nil
	}
	return msg
}