def sec(self, compressed=True):
'''returns the binary version of the SEC format'''
if compressed:
if not self.csec:
serialized = ffi.new('unsigned char [33]')
output_len = ffi.new('size_t *', 33)
lib.secp256k1_ec_pubkey_serialize(
GLOBAL_CTX,
serialized,
output_len,
self.c,
lib.SECP256K1_EC_COMPRESSED,
)
self.csec = bytes(ffi.buffer(serialized, 33))
return self.csec
else:
if not self.usec:
serialized = ffi.new('unsigned char [65]')
output_len = ffi.new('size_t *', 65)
lib.secp256k1_ec_pubkey_serialize(
GLOBAL_CTX,
serialized,
output_len,
self.c,
lib.SECP256K1_EC_UNCOMPRESSED,
)
self.usec = bytes(ffi.buffer(serialized, 65))
return self.usec
def __rmul__(self, coefficient):
coef = coefficient % N
new_key = ffi.new('secp256k1_pubkey *')
s = self.sec(compressed=False)
lib.secp256k1_ec_pubkey_parse(GLOBAL_CTX, new_key, s, len(s))
lib.secp256k1_ec_pubkey_tweak_mul(GLOBAL_CTX, new_key,
coef.to_bytes(32, 'big'))
serialized = ffi.new('unsigned char [65]')
output_len = ffi.new('size_t *', 65)
lib.secp256k1_ec_pubkey_serialize(GLOBAL_CTX, serialized, output_len,
new_key,
lib.SECP256K1_EC_UNCOMPRESSED)
return self.__class__(usec=bytes(serialized))
def __add__(self, scalar):
'''Multiplies scalar by generator, adds result to current point'''
coef = scalar % N
new_key = ffi.new('secp256k1_pubkey *')
s = self.sec(compressed=False)
lib.secp256k1_ec_pubkey_parse(GLOBAL_CTX, new_key, s, len(s))
lib.secp256k1_ec_pubkey_tweak_add(GLOBAL_CTX, new_key,
coef.to_bytes(32, 'big'))
serialized = ffi.new('unsigned char [65]')
output_len = ffi.new('size_t *', 65)
lib.secp256k1_ec_pubkey_serialize(GLOBAL_CTX, serialized, output_len,
new_key,
lib.SECP256K1_EC_UNCOMPRESSED)
return self.__class__(usec=bytes(serialized))