def decrypt_message(bip32, address_n, nonce_pub, payload, msg_hmac):
priv_node = bip32.get_private_node(address_n)
priv_key = tools.EcKey(priv_node.private_key)
shared_secret_point = tools.public_key_to_point(nonce_pub) * priv_key.privkey.secret_multiplier
shared_secret = tools.point_to_public_key(shared_secret_point, True)
keying_bytes = PBKDF2(shared_secret, "Bitcoin Secure Message" + nonce_pub, iterations=2048, macmodule=hmac, digestmodule=sha256).read(80)
aes_key = keying_bytes[:32]
hmac_key = keying_bytes[32:64]
aes_iv = keying_bytes[64:]
msg_hmac_new = hmac.HMAC(key=hmac_key, msg=payload, digestmod=sha256).digest()[:8]
if msg_hmac_new != msg_hmac:
raise Exception('Message_HMAC does not match')
decrypter = pyaes.Decrypter(pyaes.AESModeOfOperationCFB(key=aes_key, iv=aes_iv, segment_size=16))
payload = decrypter.feed(payload) + decrypter.feed()
if not ord(payload[0]) in [0x00, 0x01, 0x80, 0x81]:
raise Exception('AES decryption failed')
signing = (ord(payload[0]) & 0x01) > 0
display_only = (ord(payload[0]) & 0x80) > 0
if signing:
message = tools.deser_length_string(payload[1:-(21+65)])
address_bin = payload[-(21+65):-65]
signature = payload[-65:]
address = tools.hash_160_to_bc_address(address_bin[1:], ord(address_bin[0]))
verify_message(address, signature, message)
else:
message = tools.deser_length_string(payload[1:])
address = None
return (message, address, display_only)
def _get_address(self, coin, address_n, multisig):
if multisig:
# check if we own the pubkey
pubkey = BIP32(self.storage.get_node()).get_public_node(address_n).public_key
try:
pubkeys = [ public_ckd(n.node, list(n.address_n)).public_key for n in multisig.pubkeys ]
sig_index = list(pubkeys).index(pubkey)
except ValueError:
return proto.Failure(code=proto_types.Failure_Other, message="Pubkey not found in multisig script")
# convert script to P2SH address
script = transaction.compile_script_multisig(multisig)
h160 = tools.hash_160(script)
address = tools.hash_160_to_bc_address(h160, coin.address_type_p2sh)
else:
address = BIP32(self.storage.get_node()).get_address(coin, address_n)
self.layout.show_receiving_address(address)
self.custom_message = True # Yes button will redraw screen
return proto.Address(address=address)
