def decode_auth_ack_message(
self, ciphertext: bytes) -> Tuple[datatypes.PublicKey, bytes]:
if len(ciphertext) < ENCRYPTED_AUTH_ACK_LEN:
raise BadAckMessage(f"Auth ack msg too short: {len(ciphertext)}")
elif len(ciphertext) == ENCRYPTED_AUTH_ACK_LEN:
eph_pubkey, nonce, _ = decode_ack_plain(ciphertext, self.privkey)
else:
eph_pubkey, nonce, _ = decode_ack_eip8(ciphertext, self.privkey)
return eph_pubkey, nonce
def decode_ack_plain(
ciphertext: bytes, privkey: datatypes.PrivateKey
) -> Tuple[datatypes.PublicKey, bytes, int]:
"""Decrypts and decodes a legacy pre-EIP-8 auth ack message.
Returns the remote's ephemeral pubkey, nonce and protocol version.
"""
message = ecies.decrypt(ciphertext, privkey)
if len(message) != AUTH_ACK_LEN:
raise BadAckMessage(f"Unexpected size for ack message: {len(message)}")
eph_pubkey = keys.PublicKey(message[:PUBKEY_LEN])
nonce = message[PUBKEY_LEN:PUBKEY_LEN + HASH_LEN]
return eph_pubkey, nonce, SUPPORTED_RLPX_VERSION
def decode_auth_plain(
ciphertext: bytes, privkey: datatypes.PrivateKey
) -> Tuple[datatypes.Signature, datatypes.PublicKey, bytes, int]:
"""Decode legacy pre-EIP-8 auth message format"""
message = ecies.decrypt(ciphertext, privkey)
if len(message) != AUTH_MSG_LEN:
raise BadAckMessage(f"Unexpected size for auth message: {len(message)}")
signature = keys.Signature(signature_bytes=message[:SIGNATURE_LEN])
pubkey_start = SIGNATURE_LEN + HASH_LEN
pubkey = keys.PublicKey(message[pubkey_start : pubkey_start + PUBKEY_LEN])
nonce_start = pubkey_start + PUBKEY_LEN
nonce = message[nonce_start : nonce_start + HASH_LEN]
return signature, pubkey, nonce, SUPPORTED_RLPX_VERSION