mirror of
https://github.com/bitcoin/bitcoin.git
synced 2024-11-20 10:38:42 +01:00
227 lines
8.0 KiB
Python
227 lines
8.0 KiB
Python
# Copyright (c) 2011 Sam Rushing
|
|
"""ECC secp256k1 OpenSSL wrapper.
|
|
|
|
WARNING: This module does not mlock() secrets; your private keys may end up on
|
|
disk in swap! Use with caution!
|
|
|
|
This file is modified from python-bitcoinlib.
|
|
"""
|
|
|
|
import ctypes
|
|
import ctypes.util
|
|
import hashlib
|
|
|
|
ssl = ctypes.cdll.LoadLibrary(ctypes.util.find_library ('ssl') or 'libeay32')
|
|
|
|
ssl.BN_new.restype = ctypes.c_void_p
|
|
ssl.BN_new.argtypes = []
|
|
|
|
ssl.BN_bin2bn.restype = ctypes.c_void_p
|
|
ssl.BN_bin2bn.argtypes = [ctypes.c_char_p, ctypes.c_int, ctypes.c_void_p]
|
|
|
|
ssl.BN_CTX_free.restype = None
|
|
ssl.BN_CTX_free.argtypes = [ctypes.c_void_p]
|
|
|
|
ssl.BN_CTX_new.restype = ctypes.c_void_p
|
|
ssl.BN_CTX_new.argtypes = []
|
|
|
|
ssl.ECDH_compute_key.restype = ctypes.c_int
|
|
ssl.ECDH_compute_key.argtypes = [ctypes.c_void_p, ctypes.c_int, ctypes.c_void_p, ctypes.c_void_p]
|
|
|
|
ssl.ECDSA_sign.restype = ctypes.c_int
|
|
ssl.ECDSA_sign.argtypes = [ctypes.c_int, ctypes.c_void_p, ctypes.c_int, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p]
|
|
|
|
ssl.ECDSA_verify.restype = ctypes.c_int
|
|
ssl.ECDSA_verify.argtypes = [ctypes.c_int, ctypes.c_void_p, ctypes.c_int, ctypes.c_void_p, ctypes.c_int, ctypes.c_void_p]
|
|
|
|
ssl.EC_KEY_free.restype = None
|
|
ssl.EC_KEY_free.argtypes = [ctypes.c_void_p]
|
|
|
|
ssl.EC_KEY_new_by_curve_name.restype = ctypes.c_void_p
|
|
ssl.EC_KEY_new_by_curve_name.argtypes = [ctypes.c_int]
|
|
|
|
ssl.EC_KEY_get0_group.restype = ctypes.c_void_p
|
|
ssl.EC_KEY_get0_group.argtypes = [ctypes.c_void_p]
|
|
|
|
ssl.EC_KEY_get0_public_key.restype = ctypes.c_void_p
|
|
ssl.EC_KEY_get0_public_key.argtypes = [ctypes.c_void_p]
|
|
|
|
ssl.EC_KEY_set_private_key.restype = ctypes.c_int
|
|
ssl.EC_KEY_set_private_key.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
|
|
|
|
ssl.EC_KEY_set_conv_form.restype = None
|
|
ssl.EC_KEY_set_conv_form.argtypes = [ctypes.c_void_p, ctypes.c_int]
|
|
|
|
ssl.EC_KEY_set_public_key.restype = ctypes.c_int
|
|
ssl.EC_KEY_set_public_key.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
|
|
|
|
ssl.i2o_ECPublicKey.restype = ctypes.c_void_p
|
|
ssl.i2o_ECPublicKey.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
|
|
|
|
ssl.EC_POINT_new.restype = ctypes.c_void_p
|
|
ssl.EC_POINT_new.argtypes = [ctypes.c_void_p]
|
|
|
|
ssl.EC_POINT_free.restype = None
|
|
ssl.EC_POINT_free.argtypes = [ctypes.c_void_p]
|
|
|
|
ssl.EC_POINT_mul.restype = ctypes.c_int
|
|
ssl.EC_POINT_mul.argtypes = [ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p, ctypes.c_void_p]
|
|
|
|
# this specifies the curve used with ECDSA.
|
|
NID_secp256k1 = 714 # from openssl/obj_mac.h
|
|
|
|
SECP256K1_ORDER = 0xFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEBAAEDCE6AF48A03BBFD25E8CD0364141
|
|
SECP256K1_ORDER_HALF = SECP256K1_ORDER // 2
|
|
|
|
# Thx to Sam Devlin for the ctypes magic 64-bit fix.
|
|
def _check_result(val, func, args):
|
|
if val == 0:
|
|
raise ValueError
|
|
else:
|
|
return ctypes.c_void_p (val)
|
|
|
|
ssl.EC_KEY_new_by_curve_name.restype = ctypes.c_void_p
|
|
ssl.EC_KEY_new_by_curve_name.errcheck = _check_result
|
|
|
|
class CECKey():
|
|
"""Wrapper around OpenSSL's EC_KEY"""
|
|
|
|
POINT_CONVERSION_COMPRESSED = 2
|
|
POINT_CONVERSION_UNCOMPRESSED = 4
|
|
|
|
def __init__(self):
|
|
self.k = ssl.EC_KEY_new_by_curve_name(NID_secp256k1)
|
|
|
|
def __del__(self):
|
|
if ssl:
|
|
ssl.EC_KEY_free(self.k)
|
|
self.k = None
|
|
|
|
def set_secretbytes(self, secret):
|
|
priv_key = ssl.BN_bin2bn(secret, 32, ssl.BN_new())
|
|
group = ssl.EC_KEY_get0_group(self.k)
|
|
pub_key = ssl.EC_POINT_new(group)
|
|
ctx = ssl.BN_CTX_new()
|
|
if not ssl.EC_POINT_mul(group, pub_key, priv_key, None, None, ctx):
|
|
raise ValueError("Could not derive public key from the supplied secret.")
|
|
ssl.EC_POINT_mul(group, pub_key, priv_key, None, None, ctx)
|
|
ssl.EC_KEY_set_private_key(self.k, priv_key)
|
|
ssl.EC_KEY_set_public_key(self.k, pub_key)
|
|
ssl.EC_POINT_free(pub_key)
|
|
ssl.BN_CTX_free(ctx)
|
|
return self.k
|
|
|
|
def set_privkey(self, key):
|
|
self.mb = ctypes.create_string_buffer(key)
|
|
return ssl.d2i_ECPrivateKey(ctypes.byref(self.k), ctypes.byref(ctypes.pointer(self.mb)), len(key))
|
|
|
|
def set_pubkey(self, key):
|
|
self.mb = ctypes.create_string_buffer(key)
|
|
return ssl.o2i_ECPublicKey(ctypes.byref(self.k), ctypes.byref(ctypes.pointer(self.mb)), len(key))
|
|
|
|
def get_privkey(self):
|
|
size = ssl.i2d_ECPrivateKey(self.k, 0)
|
|
mb_pri = ctypes.create_string_buffer(size)
|
|
ssl.i2d_ECPrivateKey(self.k, ctypes.byref(ctypes.pointer(mb_pri)))
|
|
return mb_pri.raw
|
|
|
|
def get_pubkey(self):
|
|
size = ssl.i2o_ECPublicKey(self.k, 0)
|
|
mb = ctypes.create_string_buffer(size)
|
|
ssl.i2o_ECPublicKey(self.k, ctypes.byref(ctypes.pointer(mb)))
|
|
return mb.raw
|
|
|
|
def get_raw_ecdh_key(self, other_pubkey):
|
|
ecdh_keybuffer = ctypes.create_string_buffer(32)
|
|
r = ssl.ECDH_compute_key(ctypes.pointer(ecdh_keybuffer), 32,
|
|
ssl.EC_KEY_get0_public_key(other_pubkey.k),
|
|
self.k, 0)
|
|
if r != 32:
|
|
raise Exception('CKey.get_ecdh_key(): ECDH_compute_key() failed')
|
|
return ecdh_keybuffer.raw
|
|
|
|
def get_ecdh_key(self, other_pubkey, kdf=lambda k: hashlib.sha256(k).digest()):
|
|
# FIXME: be warned it's not clear what the kdf should be as a default
|
|
r = self.get_raw_ecdh_key(other_pubkey)
|
|
return kdf(r)
|
|
|
|
def sign(self, hash, low_s = True):
|
|
# FIXME: need unit tests for below cases
|
|
if not isinstance(hash, bytes):
|
|
raise TypeError('Hash must be bytes instance; got %r' % hash.__class__)
|
|
if len(hash) != 32:
|
|
raise ValueError('Hash must be exactly 32 bytes long')
|
|
|
|
sig_size0 = ctypes.c_uint32()
|
|
sig_size0.value = ssl.ECDSA_size(self.k)
|
|
mb_sig = ctypes.create_string_buffer(sig_size0.value)
|
|
result = ssl.ECDSA_sign(0, hash, len(hash), mb_sig, ctypes.byref(sig_size0), self.k)
|
|
assert 1 == result
|
|
assert mb_sig.raw[0] == 0x30
|
|
assert mb_sig.raw[1] == sig_size0.value - 2
|
|
total_size = mb_sig.raw[1]
|
|
assert mb_sig.raw[2] == 2
|
|
r_size = mb_sig.raw[3]
|
|
assert mb_sig.raw[4 + r_size] == 2
|
|
s_size = mb_sig.raw[5 + r_size]
|
|
s_value = int.from_bytes(mb_sig.raw[6+r_size:6+r_size+s_size], byteorder='big')
|
|
if (not low_s) or s_value <= SECP256K1_ORDER_HALF:
|
|
return mb_sig.raw[:sig_size0.value]
|
|
else:
|
|
low_s_value = SECP256K1_ORDER - s_value
|
|
low_s_bytes = (low_s_value).to_bytes(33, byteorder='big')
|
|
while len(low_s_bytes) > 1 and low_s_bytes[0] == 0 and low_s_bytes[1] < 0x80:
|
|
low_s_bytes = low_s_bytes[1:]
|
|
new_s_size = len(low_s_bytes)
|
|
new_total_size_byte = (total_size + new_s_size - s_size).to_bytes(1,byteorder='big')
|
|
new_s_size_byte = (new_s_size).to_bytes(1,byteorder='big')
|
|
return b'\x30' + new_total_size_byte + mb_sig.raw[2:5+r_size] + new_s_size_byte + low_s_bytes
|
|
|
|
def verify(self, hash, sig):
|
|
"""Verify a DER signature"""
|
|
return ssl.ECDSA_verify(0, hash, len(hash), sig, len(sig), self.k) == 1
|
|
|
|
def set_compressed(self, compressed):
|
|
if compressed:
|
|
form = self.POINT_CONVERSION_COMPRESSED
|
|
else:
|
|
form = self.POINT_CONVERSION_UNCOMPRESSED
|
|
ssl.EC_KEY_set_conv_form(self.k, form)
|
|
|
|
|
|
class CPubKey(bytes):
|
|
"""An encapsulated public key
|
|
|
|
Attributes:
|
|
|
|
is_valid - Corresponds to CPubKey.IsValid()
|
|
is_fullyvalid - Corresponds to CPubKey.IsFullyValid()
|
|
is_compressed - Corresponds to CPubKey.IsCompressed()
|
|
"""
|
|
|
|
def __new__(cls, buf, _cec_key=None):
|
|
self = super(CPubKey, cls).__new__(cls, buf)
|
|
if _cec_key is None:
|
|
_cec_key = CECKey()
|
|
self._cec_key = _cec_key
|
|
self.is_fullyvalid = _cec_key.set_pubkey(self) != 0
|
|
return self
|
|
|
|
@property
|
|
def is_valid(self):
|
|
return len(self) > 0
|
|
|
|
@property
|
|
def is_compressed(self):
|
|
return len(self) == 33
|
|
|
|
def verify(self, hash, sig):
|
|
return self._cec_key.verify(hash, sig)
|
|
|
|
def __str__(self):
|
|
return repr(self)
|
|
|
|
def __repr__(self):
|
|
return '%s(%s)' % (self.__class__.__name__, super(CPubKey, self).__repr__())
|
|
|