def test_shared_secrets_equal(self):
wifs = cycle([x[0] for x in test_shared_secrets])
for i in range(len(test_shared_secrets)):
sender_private_key = PrivateKey(next(wifs))
sender_public_key = sender_private_key.pubkey
receiver_private_key = PrivateKey(next(wifs))
receiver_public_key = receiver_private_key.pubkey
self.assertEqual(
get_shared_secret(sender_private_key, receiver_public_key),
get_shared_secret(receiver_private_key, sender_public_key),
)
def encode_memo(priv, pub, nonce, message, **kwargs):
"""
Encode a message with a shared secret between Alice and Bob.
:param PrivateKey priv: Private Key (of Alice)
:param PublicKey pub: Public Key (of Bob)
:param int nonce: Random nonce
:param str message: Memo message
:return: Encrypted message
:rtype: hex
"""
shared_secret = get_shared_secret(priv, pub)
aes, check = init_aes(shared_secret, nonce)
raw = bytes(message, "utf8")
" Padding "
bs = 16
if len(raw) % bs:
raw = _pad(raw, bs)
" Encryption "
cipher = hexlify(aes.encrypt(raw)).decode("ascii")
prefix = kwargs.pop("prefix")
op = {
"from": format(priv.pubkey, prefix),
"to": format(pub, prefix),
"nonce": nonce,
"check": check,
"encrypted": cipher,
}
tx = Memo(**op)
return "#" + base58encode(hexlify(bytes(tx)).decode("ascii"))
def decode_memo(priv, message):
"""
Decode a message with a shared secret between Alice and Bob.
:param PrivateKey priv: Private Key (of Bob)
:param base58encoded message: Encrypted Memo message
:return: Decrypted message
:rtype: str
:raise ValueError: if message cannot be decoded as valid UTF-8
string
"""
" decode structure "
raw = base58decode(message[1:])
from_key = PublicKey(raw[:66])
raw = raw[66:]
to_key = PublicKey(raw[:66])
raw = raw[66:]
nonce = str(struct.unpack_from("<Q", unhexlify(raw[:16]))[0])
raw = raw[16:]
check = struct.unpack_from("<I", unhexlify(raw[:8]))[0]
raw = raw[8:]
cipher = raw
if repr(to_key) == repr(priv.pubkey):
shared_secret = get_shared_secret(priv, from_key)
elif repr(from_key) == repr(priv.pubkey):
shared_secret = get_shared_secret(priv, to_key)
else:
raise ValueError("Incorrect PrivateKey")
" Init encryption "
aes, checksum = init_aes(shared_secret, nonce)
" Check "
assert check == checksum, "Checksum failure"
" Encryption "
# remove the varint prefix (FIXME, long messages!)
message = cipher[2:]
message = aes.decrypt(unhexlify(bytes(message, "ascii")))
try:
return _unpad(message.decode("utf8"), 16)
except Exception:
raise ValueError(message)
def test_shared_secret(self):
for s in test_shared_secrets:
priv = PrivateKey(s[0])
pub = PublicKey(s[1], prefix="GPH")
shared_secret = get_shared_secret(priv, pub)
self.assertEqual(s[2], shared_secret)
def test_shared_secret(self):
for s in test_shared_secrets:
priv = PrivateKey(s[0])
pub = PublicKey(s[1], prefix="GPH")
shared_secret = get_shared_secret(priv, pub)
self.assertEqual(s[2], shared_secret)