lnbits-legend/lnbits/extensions/cashu/core/secp.py

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2022-10-07 10:09:16 +03:00
from secp256k1 import PrivateKey, PublicKey
# We extend the public key to define some operations on points
# Picked from https://github.com/WTRMQDev/secp256k1-zkp-py/blob/master/secp256k1_zkp/__init__.py
class PublicKeyExt(PublicKey):
def __add__(self, pubkey2):
if isinstance(pubkey2, PublicKey):
new_pub = PublicKey()
new_pub.combine([self.public_key, pubkey2.public_key])
return new_pub
else:
raise TypeError("Cant add pubkey and %s" % pubkey2.__class__)
def __neg__(self):
serialized = self.serialize()
first_byte, remainder = serialized[:1], serialized[1:]
# flip odd/even byte
first_byte = {b"\x03": b"\x02", b"\x02": b"\x03"}[first_byte]
return PublicKey(first_byte + remainder, raw=True)
def __sub__(self, pubkey2):
if isinstance(pubkey2, PublicKey):
return self + (-pubkey2)
else:
raise TypeError("Can't add pubkey and %s" % pubkey2.__class__)
def mult(self, privkey):
if isinstance(privkey, PrivateKey):
return self.tweak_mul(privkey.private_key)
else:
raise TypeError("Can't multiply with non privatekey")
def __eq__(self, pubkey2):
if isinstance(pubkey2, PublicKey):
seq1 = self.to_data()
seq2 = pubkey2.to_data()
return seq1 == seq2
else:
raise TypeError("Can't compare pubkey and %s" % pubkey2.__class__)
def to_data(self):
return [self.public_key.data[i] for i in range(64)]
# Horrible monkeypatching
PublicKey.__add__ = PublicKeyExt.__add__
PublicKey.__neg__ = PublicKeyExt.__neg__
PublicKey.__sub__ = PublicKeyExt.__sub__
PublicKey.mult = PublicKeyExt.mult
PublicKey.__eq__ = PublicKeyExt.__eq__
PublicKey.to_data = PublicKeyExt.to_data