Minor refactoring to separate objects

python3android
Peter Šurda 3 years ago
parent 076aeaa19f
commit b934c4e01e
Signed by untrusted user: PeterSurda
GPG Key ID: 0C5F50C0B5F37D87
  1. 79
      src/pyelliptic/eccblind.py
  2. 25
      src/tests/test_blindsig.py

@ -64,24 +64,43 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
OpenSSL.EC_POINT_mul(group, Q, d, 0, 0, 0)
return (d, Q)
def __init__(self, curve="secp256k1"):
self.group = OpenSSL.EC_GROUP_new_by_curve_name(OpenSSL.get_curve(curve))
@staticmethod
def ec_Ftor(F, group, ctx):
"""
x0 coordinate of F
"""
# F = (x0, y0)
x0 = OpenSSL.BN_new()
y0 = OpenSSL.BN_new()
OpenSSL.EC_POINT_get_affine_coordinates_GFp(group, F, x0, y0,
ctx)
return x0
def __init__(self, curve="secp256k1", pubkey=None):
self.ctx = OpenSSL.BN_CTX_new()
# Order n
self.n = OpenSSL.BN_new()
OpenSSL.EC_GROUP_get_order(self.group, self.n, self.ctx)
if pubkey:
self.group, self.G, self.n, self.Q = pubkey
else:
self.group = OpenSSL.EC_GROUP_new_by_curve_name(OpenSSL.get_curve(curve))
# Order n
self.n = OpenSSL.BN_new()
OpenSSL.EC_GROUP_get_order(self.group, self.n, self.ctx)
# Generator G
self.G = OpenSSL.EC_GROUP_get0_generator(self.group)
# new keypair
self.keypair = ECCBlind.ec_gen_keypair(self.group, self.ctx)
self.Q = self.keypair[1]
self.pubkey = (self.group, self.G, self.n, self.Q)
# Identity O (infinity)
self.iO = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_set_to_infinity(self.group, self.iO)
# Generator G
self.G = OpenSSL.EC_GROUP_get0_generator(self.group)
# Certifier's pubkey
self.pubkey = (self.group, self.G, self.n)
def signer_init(self):
"""
Init signer
@ -93,18 +112,18 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
self.R = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_mul(self.group, self.R, self.k, 0, 0, 0)
def create_signing_request(self, msg):
return self.R
def create_signing_request(self, R, msg):
"""
Requester creates a new signing request
"""
# new keypair
self.keypair = ECCBlind.ec_gen_keypair(self.group, self.ctx)
self.R = R
# Requester: 3 random blinding factors
self.F = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_set_to_infinity(self.group, self.F)
temp = OpenSSL.EC_POINT_new(self.group)
self.Q = self.keypair[1]
abinv = OpenSSL.BN_new()
# F != O
@ -128,11 +147,7 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
OpenSSL.EC_POINT_add(self.group, self.F, self.F, temp, 0)
# F = (x0, y0)
x0 = OpenSSL.BN_new()
y0 = OpenSSL.BN_new()
OpenSSL.EC_POINT_get_affine_coordinates_GFp(self.group, self.F, x0, y0,
self.ctx)
self.r = x0
self.r = ECCBlind.ec_Ftor(self.F, self.group, self.ctx)
# Requester: Blinding (m' = br(m) + a)
self.m = OpenSSL.BN_new()
@ -142,32 +157,48 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
OpenSSL.BN_mod_mul(self.m_, self.b, self.r, self.n, self.ctx)
OpenSSL.BN_mod_mul(self.m_, self.m_, self.m, self.n, self.ctx)
OpenSSL.BN_mod_add(self.m_, self.m_, self.a, self.n, self.ctx)
return self.m_
def blind_sign(self):
def blind_sign(self, m_):
"""
Signer blind-signs the request
"""
self.m_ = m_
self.s_ = OpenSSL.BN_new()
OpenSSL.BN_mod_mul(self.s_, self.keypair[0], self.m_, self.n, self.ctx)
OpenSSL.BN_mod_add(self.s_, self.s_, self.k, self.n, self.ctx)
return self.s_
def unblind(self):
def unblind(self, s_):
"""
Requester unblinds the signature
"""
self.s_ = s_
s = OpenSSL.BN_new()
OpenSSL.BN_mod_mul(s, self.binv, self.s_, self.n, self.ctx)
OpenSSL.BN_mod_add(s, s, self.c, self.n, self.ctx)
self.signature = (s, self.F)
return self.signature
def verify(self):
def verify(self, msg, signature):
"""
Verify signature with certifier's pubkey
"""
# convert msg to BIGNUM
self.m = OpenSSL.BN_new()
OpenSSL.BN_bin2bn(msg, len(msg), self.m)
# init
s, self.F = signature
if self.r is None:
self.r = ECCBlind.ec_Ftor(self.F, self.group, self.ctx)
lhs = OpenSSL.EC_POINT_new(self.group)
rhs = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_mul(self.group, lhs, self.signature[0], 0, 0, 0)
OpenSSL.EC_POINT_mul(self.group, lhs, s, 0, 0, 0)
OpenSSL.EC_POINT_mul(self.group, rhs, 0, self.Q, self.m, 0)
OpenSSL.EC_POINT_mul(self.group, rhs, 0, rhs, self.r, 0)
OpenSSL.EC_POINT_add(self.group, rhs, rhs, self.F, self.ctx)

@ -13,10 +13,23 @@ class TestBlindSig(unittest.TestCase):
"""
def test_blind_sig(self):
"""Test full sequence using a random certifier key and a random message"""
blind_sig = ECCBlind()
blind_sig.signer_init()
# See page 127 of the paper
# (1) Initialization
signer_obj = ECCBlind()
point_r = signer_obj.signer_init()
# (2) Request
requester_obj = ECCBlind(pubkey=signer_obj.pubkey)
# only 64 byte messages are planned to be used in Bitmessage
msg = os.urandom(64)
blind_sig.create_signing_request(msg)
blind_sig.blind_sign()
blind_sig.unblind()
self.assertTrue(blind_sig.verify())
msg_blinded = requester_obj.create_signing_request(point_r, msg)
# (3) Signature Generation
signature_blinded = signer_obj.blind_sign(msg_blinded)
# (4) Extraction
signature = requester_obj.unblind(signature_blinded)
# (5) Verification
verifier_obj = ECCBlind(pubkey=signer_obj.pubkey)
self.assertTrue(verifier_obj.verify(msg, signature))

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