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Blind signature updates

- added serializing and deserializing
- added a signature chain class `ECCBlindSigChain`
- added more tests
v0.6
Peter Šurda 2 years ago
parent
commit
ff1f451691
Signed by untrusted user: PeterSurda GPG Key ID: 0C5F50C0B5F37D87
  1. 2
      src/pyelliptic/__init__.py
  2. 77
      src/pyelliptic/blindchain.py
  3. 316
      src/pyelliptic/eccblind.py
  4. 52
      src/pyelliptic/eccblindchain.py
  5. 82
      src/pyelliptic/openssl.py
  6. 262
      src/tests/test_blindsig.py
  7. 54
      src/tests/test_openssl.py

2
src/pyelliptic/__init__.py

@ -12,6 +12,7 @@ This is an abandoned package maintained inside of the PyBitmessage.
from .cipher import Cipher
from .ecc import ECC
from .eccblind import ECCBlind
from .eccblindchain import ECCBlindChain
from .hash import hmac_sha256, hmac_sha512, pbkdf2
from .openssl import OpenSSL
@ -21,6 +22,7 @@ __all__ = [
'OpenSSL',
'ECC',
'ECCBlind',
'ECCBlindChain',
'Cipher',
'hmac_sha256',
'hmac_sha512',

77
src/pyelliptic/blindchain.py

@ -1,77 +0,0 @@
"""
Blind signature chain with a top level CA
"""
from eccblind import ECCBlind
try:
import msgpack
except ImportError:
try:
import umsgpack as msgpack
except ImportError:
import fallback.umsgpack.umsgpack as msgpack
from eccblind import ECCBlind
def encode_datetime(obj):
"""
Method to format time
"""
return {'Time': int(obj.strftime("%s"))}
class ECCBlindChain(object): # pylint: disable=too-many-instance-attributes
"""
# Class for ECC Blind Chain signature functionality
"""
chain = []
ca = []
def __init__(self, chain=None):
if chain is not None:
self.chain = chain
def serialize(self):
data = msgpack.packb(self.chain)
return data
@staticmethod
def deserialize(self, chain):
"""
Deserialize the data using msgpack
"""
data = msgpack.unpackb(chain)
return ECCBlindChain(data)
def add_level(self, pubkey, metadata, signature):
self.chain.append((pubkey, metadata, signature))
def add_ca(self, ca):
pubkey, metadata = ECCBlind.deserialize(ca)
self.ca.append(pubkey)
def verify(self, msg, value):
lastpubkey = None
retval = False
for level in reversed(self.chain):
pubkey, metadata, signature = level
verifier_obj = ECCBlind(pubkey=pubkey, metadata)
if not lastpubkey:
retval = verifier_obj.verify(msg, signature, value)
else:
retval = verifier_obj.verify(lastpubkey, signature, value)
if not reval:
break
lastpubkey = pubkey
if retval:
retval = False
for ca in self.ca:
match = True
for i in range(4):
if lastpubkey[i] != ca[i]:
match = False
break
if match:
return True
return retval

316
src/pyelliptic/eccblind.py

@ -10,50 +10,69 @@ http://www.isecure-journal.com/article_39171_47f9ec605dd3918c2793565ec21fcd7a.pd
# variable names are based on the math in the paper, so they don't conform
# to PEP8
from hashlib import sha256
import time
try:
import msgpack
except ImportError:
try:
import umsgpack as msgpack
except ImportError:
import fallback.umsgpack.umsgpack as msgpack
from hashlib import sha256
from struct import pack, unpack
from .openssl import OpenSSL
# first byte in serialisation can contain data
Y_BIT = 0x01
COMPRESSED_BIT = 0x02
class Metadata(object):
"""
Pubkey metadata
"""
def __init__(self, exp=0, value=0):
self.exp = 0
self.value = 0
if exp:
self.exp = exp
if value:
self.value = value
# formats
BIGNUM = '!32s'
EC = '!B32s'
PUBKEY = '!BB33s'
class Expiration(object):
"""Expiration of pubkey"""
@staticmethod
def deserialize(val):
"""Create an object out of int"""
year = ((val & 0xF0) >> 4) + 2020
month = val & 0x0F
assert month < 12
return Expiration(year, month)
def __init__(self, year, month):
assert isinstance(year, int)
assert year > 2019 and year < 2036
assert isinstance(month, int)
assert month < 12
self.year = year
self.month = month
self.exp = year + month / 12.0
def serialize(self):
if self.exp or self.value:
return [self.exp, self.value]
else:
return []
"""Make int out of object"""
return ((self.year - 2020) << 4) + self.month
def verify(self):
"""Check if the pubkey has expired"""
now = time.gmtime()
return self.exp >= now.tm_year + (now.tm_mon - 1) / 12.0
class Value(object):
"""Value of a pubkey"""
@staticmethod
def deserialize(self, data):
exp, value = data
return Medatadata(exp, value)
def deserialize(val):
"""Make object out of int"""
return Value(val)
def __init__(self, value=0xFF):
assert isinstance(value, int)
self.value = value
def serialize(self):
"""Make int out of object"""
return self.value & 0xFF
def verify(self, value):
if self.value and value > self.value:
return False
if self.exp:
if time.time() > self.exp:
return False
return True
"""Verify against supplied value"""
return value <= self.value
class ECCBlind(object): # pylint: disable=too-many-instance-attributes
@ -64,8 +83,8 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
# init
k = None
R = None
keypair = None
F = None
d = None
Q = None
a = None
b = None
@ -76,115 +95,183 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
m_ = None
s_ = None
signature = None
exp = None
val = None
@staticmethod
def ec_get_random(group, ctx):
def ec_get_random(self):
"""
Random point from finite field
Random integer within the EC order
"""
order = OpenSSL.BN_new()
OpenSSL.EC_GROUP_get_order(group, order, ctx)
OpenSSL.BN_rand(order, OpenSSL.BN_num_bits(order), 0, 0)
return order
randomnum = OpenSSL.BN_new()
OpenSSL.BN_rand(randomnum, OpenSSL.BN_num_bits(self.n), 0, 0)
return randomnum
@staticmethod
def ec_invert(group, a, ctx):
def ec_invert(self, a):
"""
ECC inversion
"""
order = OpenSSL.BN_new()
OpenSSL.EC_GROUP_get_order(group, order, ctx)
inverse = OpenSSL.BN_mod_inverse(0, a, order, ctx)
inverse = OpenSSL.BN_mod_inverse(0, a, self.n, self.ctx)
return inverse
@staticmethod
def ec_gen_keypair(group, ctx):
def ec_gen_keypair(self):
"""
Generate an ECC keypair
We're using compressed keys
"""
d = ECCBlind.ec_get_random(group, ctx)
Q = OpenSSL.EC_POINT_new(group)
OpenSSL.EC_POINT_mul(group, Q, d, 0, 0, 0)
d = self.ec_get_random()
Q = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_mul(self.group, Q, d, 0, 0, 0)
return (d, Q)
@staticmethod
def ec_Ftor(F, group, ctx):
def ec_Ftor(self, F):
"""
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)
OpenSSL.EC_POINT_get_affine_coordinates(self.group, F, x0, y0, self.ctx)
OpenSSL.BN_free(y0)
return x0
@staticmethod
def deserialize(self, data):
pubkey_deserialized, meta = msgpack.unpackb(data)
if meta:
obj = ECCBlind(pubkey=pubkey_deserialized, metadata=meta)
else:
obj = ECCBlind(pubkey=pubkey_deserialized)
return obj
def serialize(self):
data = (self.pubkey, self.metadata.serialize)
retval = msgpack.packb(data)
def _ec_point_serialize(self, point):
"""Make an EC point into a string"""
try:
x = OpenSSL.BN_new()
y = OpenSSL.BN_new()
OpenSSL.EC_POINT_get_affine_coordinates(
self.group, point, x, y, 0)
y_byte = (OpenSSL.BN_is_odd(y) & Y_BIT) | COMPRESSED_BIT
l_ = OpenSSL.BN_num_bytes(self.n)
try:
bx = OpenSSL.malloc(0, l_)
OpenSSL.BN_bn2binpad(x, bx, l_)
out = bx.raw
except AttributeError:
# padding manually
bx = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(x))
OpenSSL.BN_bn2bin(x, bx)
out = bx.raw.rjust(l_, chr(0))
return pack(EC, y_byte, out)
finally:
OpenSSL.BN_clear_free(x)
OpenSSL.BN_clear_free(y)
def _ec_point_deserialize(self, data):
"""Make a string into an EC point"""
y_bit, x_raw = unpack(EC, data)
x = OpenSSL.BN_bin2bn(x_raw, OpenSSL.BN_num_bytes(self.n), 0)
y_bit &= Y_BIT
retval = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_set_compressed_coordinates(self.group,
retval,
x,
y_bit,
self.ctx)
return retval
def __init__(self, curve="secp256k1", pubkey=None, metadata=None):
def _bn_serialize(self, bn):
"""Make a string out of BigNum"""
l_ = OpenSSL.BN_num_bytes(self.n)
try:
o = OpenSSL.malloc(0, l_)
OpenSSL.BN_bn2binpad(bn, o, l_)
return o.raw
except AttributeError:
o = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(bn))
OpenSSL.BN_bn2bin(bn, o)
return o.raw.rjust(l_, chr(0))
def _bn_deserialize(self, data):
"""Make a BigNum out of string"""
x = OpenSSL.BN_bin2bn(data, OpenSSL.BN_num_bytes(self.n), 0)
return x
def _init_privkey(self, privkey):
"""Initialise private key out of string/bytes"""
self.d = self._bn_deserialize(privkey)
def privkey(self):
"""Make a private key into a string"""
return pack(BIGNUM, self.d)
def _init_pubkey(self, pubkey):
"""Initialise pubkey out of string/bytes"""
unpacked = unpack(PUBKEY, pubkey)
self.expiration = Expiration.deserialize(unpacked[0])
self.value = Value.deserialize(unpacked[1])
self.Q = self._ec_point_deserialize(unpacked[2])
def pubkey(self):
"""Make a pubkey into a string"""
return pack(PUBKEY, self.expiration.serialize(),
self.value.serialize(),
self._ec_point_serialize(self.Q))
def __init__(self, curve="secp256k1", pubkey=None, privkey=None, # pylint: disable=too-many-arguments
year=2025, month=11, value=0xFF):
self.ctx = OpenSSL.BN_CTX_new()
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)
# ECC group
self.group = OpenSSL.EC_GROUP_new_by_curve_name(
OpenSSL.get_curve(curve))
self.Q = self.keypair[1]
# Order n
self.n = OpenSSL.BN_new()
OpenSSL.EC_GROUP_get_order(self.group, self.n, self.ctx)
self.pubkey = (self.group, self.G, self.n, self.Q)
# Generator G
self.G = OpenSSL.EC_GROUP_get0_generator(self.group)
# Identity O (infinity)
self.iO = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_set_to_infinity(self.group, self.iO)
if metadata:
self._set_metadata(self, metadata)
else:
self.metadata = Metadata()
def _set_metadata(self, metadata):
self.metadata = Metadata.deserialise(metadata)
if privkey:
assert pubkey
# load both pubkey and privkey from bytes
self._init_privkey(privkey)
self._init_pubkey(pubkey)
elif pubkey:
# load pubkey from bytes
self._init_pubkey(pubkey)
else:
# new keypair
self.d, self.Q = self.ec_gen_keypair()
if not year or not month:
now = time.gmtime()
if now.tm_mon == 12:
self.expiration = Expiration(now.tm_year + 1, 1)
else:
self.expiration = Expiration(now.tm_year, now.tm_mon + 1)
else:
self.expiration = Expiration(year, month)
self.value = Value(value)
def __del__(self):
OpenSSL.BN_free(self.n)
OpenSSL.BN_CTX_free(self.ctx)
def signer_init(self):
"""
Init signer
"""
# Signer: Random integer k
self.k = ECCBlind.ec_get_random(self.group, self.ctx)
self.k = self.ec_get_random()
# R = kG
self.R = OpenSSL.EC_POINT_new(self.group)
OpenSSL.EC_POINT_mul(self.group, self.R, self.k, 0, 0, 0)
return self.R
return self._ec_point_serialize(self.R)
def create_signing_request(self, R, msg):
"""
Requester creates a new signing request
"""
self.R = R
msghash = sha256(msg)
self.R = self._ec_point_deserialize(R)
msghash = sha256(msg).digest()
# Requester: 3 random blinding factors
self.F = OpenSSL.EC_POINT_new(self.group)
@ -194,12 +281,12 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
# F != O
while OpenSSL.EC_POINT_cmp(self.group, self.F, self.iO, self.ctx) == 0:
self.a = ECCBlind.ec_get_random(self.group, self.ctx)
self.b = ECCBlind.ec_get_random(self.group, self.ctx)
self.c = ECCBlind.ec_get_random(self.group, self.ctx)
self.a = self.ec_get_random()
self.b = self.ec_get_random()
self.c = self.ec_get_random()
# F = b^-1 * R...
self.binv = ECCBlind.ec_invert(self.group, self.b, self.ctx)
self.binv = self.ec_invert(self.b)
OpenSSL.EC_POINT_mul(self.group, temp, 0, self.R, self.binv, 0)
OpenSSL.EC_POINT_copy(self.F, temp)
@ -213,7 +300,7 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
OpenSSL.EC_POINT_add(self.group, self.F, self.F, temp, 0)
# F = (x0, y0)
self.r = ECCBlind.ec_Ftor(self.F, self.group, self.ctx)
self.r = self.ec_Ftor(self.F)
# Requester: Blinding (m' = br(m) + a)
self.m = OpenSSL.BN_new()
@ -223,43 +310,48 @@ 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_
return self._bn_serialize(self.m_)
def blind_sign(self, m_):
"""
Signer blind-signs the request
"""
self.m_ = m_
self.m_ = self._bn_deserialize(m_)
self.s_ = OpenSSL.BN_new()
OpenSSL.BN_mod_mul(self.s_, self.keypair[0], self.m_, self.n, self.ctx)
OpenSSL.BN_mod_mul(self.s_, self.d, self.m_, self.n, self.ctx)
OpenSSL.BN_mod_add(self.s_, self.s_, self.k, self.n, self.ctx)
return self.s_
OpenSSL.BN_free(self.k)
return self._bn_serialize(self.s_)
def unblind(self, s_):
"""
Requester unblinds the signature
"""
self.s_ = s_
self.s_ = self._bn_deserialize(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)
OpenSSL.BN_free(self.a)
OpenSSL.BN_free(self.b)
OpenSSL.BN_free(self.c)
self.signature = (s, self.F)
return self.signature
return self._bn_serialize(s) + self._ec_point_serialize(self.F)
def verify(self, msg, signature, value=0):
def verify(self, msg, signature, value=1):
"""
Verify signature with certifier's pubkey
"""
# convert msg to BIGNUM
self.m = OpenSSL.BN_new()
msghash = sha256(msg)
msghash = sha256(msg).digest()
OpenSSL.BN_bin2bn(msghash, len(msghash), self.m)
# init
s, self.F = signature
s, self.F = (self._bn_deserialize(signature[0:32]),
self._ec_point_deserialize(signature[32:]))
if self.r is None:
self.r = ECCBlind.ec_Ftor(self.F, self.group, self.ctx)
self.r = self.ec_Ftor(self.F)
lhs = OpenSSL.EC_POINT_new(self.group)
rhs = OpenSSL.EC_POINT_new(self.group)
@ -273,8 +365,10 @@ class ECCBlind(object): # pylint: disable=too-many-instance-attributes
retval = OpenSSL.EC_POINT_cmp(self.group, lhs, rhs, self.ctx)
if retval == -1:
raise RuntimeError("EC_POINT_cmp returned an error")
elif not self.value.verify(value):
return False
elif not self.expiration.verify():
return False
elif retval != 0:
return False
elif self.metadata:
return self.metadata.verify(value)
return True

52
src/pyelliptic/eccblindchain.py

@ -0,0 +1,52 @@
"""
Blind signature chain with a top level CA
"""
from .eccblind import ECCBlind
class ECCBlindChain(object): # pylint: disable=too-few-public-methods
"""
# Class for ECC Blind Chain signature functionality
"""
def __init__(self, ca=None, chain=None):
self.chain = []
self.ca = []
if ca:
for i in range(0, len(ca), 35):
self.ca.append(ca[i:i + 35])
if chain:
self.chain.append(chain[0:35])
for i in range(35, len(chain), 100):
if len(chain[i:]) == 65:
self.chain.append(chain[i:i + 65])
else:
self.chain.append(chain[i:i + 100])
def verify(self, msg, value):
"""Verify a chain provides supplied message and value"""
parent = None
l_ = 0
for level in self.chain:
l_ += 1
pubkey = None
signature = None
if len(level) == 100:
pubkey, signature = (level[0:35], level[35:])
elif len(level) == 35:
if level not in self.ca:
return False
parent = level
continue
else:
signature = level
verifier_obj = ECCBlind(pubkey=parent)
if pubkey:
if not verifier_obj.verify(pubkey, signature, value):
return False
parent = pubkey
else:
return verifier_obj.verify(msg=msg, signature=signature,
value=value)
return None

82
src/pyelliptic/openssl.py

@ -8,6 +8,7 @@ needed openssl functionality in class _OpenSSL.
"""
import ctypes
import sys
# pylint: disable=protected-access
OpenSSL = None
@ -97,6 +98,10 @@ class _OpenSSL(object):
self.BN_free.restype = None
self.BN_free.argtypes = [ctypes.c_void_p]
self.BN_clear_free = self._lib.BN_clear_free
self.BN_clear_free.restype = None
self.BN_clear_free.argtypes = [ctypes.c_void_p]
self.BN_num_bits = self._lib.BN_num_bits
self.BN_num_bits.restype = ctypes.c_int
self.BN_num_bits.argtypes = [ctypes.c_void_p]
@ -105,6 +110,15 @@ class _OpenSSL(object):
self.BN_bn2bin.restype = ctypes.c_int
self.BN_bn2bin.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
try:
self.BN_bn2binpad = self._lib.BN_bn2binpad
self.BN_bn2binpad.restype = ctypes.c_int
self.BN_bn2binpad.argtypes = [ctypes.c_void_p, ctypes.c_void_p,
ctypes.c_int]
except AttributeError:
# optional, we have a workaround
pass
self.BN_bin2bn = self._lib.BN_bin2bn
self.BN_bin2bn.restype = ctypes.c_void_p
self.BN_bin2bn.argtypes = [ctypes.c_void_p, ctypes.c_int,
@ -147,6 +161,20 @@ class _OpenSSL(object):
ctypes.c_void_p,
ctypes.c_void_p]
try:
self.EC_POINT_get_affine_coordinates = \
self._lib.EC_POINT_get_affine_coordinates
except AttributeError:
# OpenSSL docs say only use this for backwards compatibility
self.EC_POINT_get_affine_coordinates = \
self._lib.EC_POINT_get_affine_coordinates_GF2m
self.EC_POINT_get_affine_coordinates.restype = ctypes.c_int
self.EC_POINT_get_affine_coordinates.argtypes = [ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p]
self.EC_KEY_set_private_key = self._lib.EC_KEY_set_private_key
self.EC_KEY_set_private_key.restype = ctypes.c_int
self.EC_KEY_set_private_key.argtypes = [ctypes.c_void_p,
@ -171,6 +199,34 @@ class _OpenSSL(object):
ctypes.c_void_p,
ctypes.c_void_p]
try:
self.EC_POINT_set_affine_coordinates = \
self._lib.EC_POINT_set_affine_coordinates
except AttributeError:
# OpenSSL docs say only use this for backwards compatibility
self.EC_POINT_set_affine_coordinates = \
self._lib.EC_POINT_set_affine_coordinates_GF2m
self.EC_POINT_set_affine_coordinates.restype = ctypes.c_int
self.EC_POINT_set_affine_coordinates.argtypes = [ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p]
try:
self.EC_POINT_set_compressed_coordinates = \
self._lib.EC_POINT_set_compressed_coordinates
except AttributeError:
# OpenSSL docs say only use this for backwards compatibility
self.EC_POINT_set_compressed_coordinates = \
self._lib.EC_POINT_set_compressed_coordinates_GF2m
self.EC_POINT_set_compressed_coordinates.restype = ctypes.c_int
self.EC_POINT_set_compressed_coordinates.argtypes = [ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_void_p,
ctypes.c_int,
ctypes.c_void_p]
self.EC_POINT_new = self._lib.EC_POINT_new
self.EC_POINT_new.restype = ctypes.c_void_p
self.EC_POINT_new.argtypes = [ctypes.c_void_p]
@ -215,10 +271,6 @@ class _OpenSSL(object):
self._lib.ECDH_set_method.argtypes = [ctypes.c_void_p,
ctypes.c_void_p]
self.BN_CTX_new = self._lib.BN_CTX_new
self._lib.BN_CTX_new.restype = ctypes.c_void_p
self._lib.BN_CTX_new.argtypes = []
self.ECDH_compute_key = self._lib.ECDH_compute_key
self.ECDH_compute_key.restype = ctypes.c_int
self.ECDH_compute_key.argtypes = [ctypes.c_void_p,
@ -477,13 +529,19 @@ class _OpenSSL(object):
self.BN_cmp.argtypes = [ctypes.c_void_p,
ctypes.c_void_p]
try:
self.BN_is_odd = self._lib.BN_is_odd
self.BN_is_odd.restype = ctypes.c_int
self.BN_is_odd.argtypes = [ctypes.c_void_p]
except AttributeError:
# OpenSSL 1.1.0 implements this as a function, but earlier
# versions as macro, so we need to workaround
self.BN_is_odd = self.BN_is_odd_compatible
self.BN_bn2dec = self._lib.BN_bn2dec
self.BN_bn2dec.restype = ctypes.c_char_p
self.BN_bn2dec.argtypes = [ctypes.c_void_p]
self.BN_CTX_free = self._lib.BN_CTX_free
self.BN_CTX_free.argtypes = [ctypes.c_void_p]
self.EC_GROUP_new_by_curve_name = self._lib.EC_GROUP_new_by_curve_name
self.EC_GROUP_new_by_curve_name.restype = ctypes.c_void_p
self.EC_GROUP_new_by_curve_name.argtypes = [ctypes.c_int]
@ -600,6 +658,16 @@ class _OpenSSL(object):
"""
return int((self.BN_num_bits(x) + 7) / 8)
def BN_is_odd_compatible(self, x):
"""
returns if BN is odd
we assume big endianness, and that BN is initialised
"""
length = self.BN_num_bytes(x)
data = self.malloc(0, length)
OpenSSL.BN_bn2bin(x, data)
return ord(data[length - 1]) & 1
def get_cipher(self, name):
"""
returns the OpenSSL cipher instance

262
src/tests/test_blindsig.py

@ -2,14 +2,15 @@
Test for ECC blind signatures
"""
import os
import time
import unittest
from ctypes import cast, c_char_p
from hashlib import sha256
from pybitmessage.pyelliptic.eccblind import ECCBlind, Metadata
from pybitmessage.pyelliptic.eccblind import ECCBlind
from pybitmessage.pyelliptic.eccblindchain import ECCBlindChain
from pybitmessage.pyelliptic.openssl import OpenSSL
# pylint: disable=protected-access
class TestBlindSig(unittest.TestCase):
"""
@ -21,78 +22,255 @@ class TestBlindSig(unittest.TestCase):
# (1) Initialization
signer_obj = ECCBlind()
point_r = signer_obj.signer_init()
self.assertEqual(len(signer_obj.pubkey()), 35)
# (2) Request
requester_obj = ECCBlind(pubkey=signer_obj.pubkey)
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
# only 64 byte messages are planned to be used in Bitmessage
msg = os.urandom(64)
msg_blinded = requester_obj.create_signing_request(point_r, msg)
self.assertEqual(len(msg_blinded), 32)
# check
msg_blinded_str = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(msg_blinded))
OpenSSL.BN_bn2bin(msg_blinded, msg_blinded_str)
self.assertNotEqual(msg, cast(msg_blinded_str, c_char_p).value)
self.assertNotEqual(sha256(msg).digest(), msg_blinded)
# (3) Signature Generation
signature_blinded = signer_obj.blind_sign(msg_blinded)
assert isinstance(signature_blinded, str)
self.assertEqual(len(signature_blinded), 32)
# (4) Extraction
signature = requester_obj.unblind(signature_blinded)
assert isinstance(signature, str)
self.assertEqual(len(signature), 65)
# check
signature_blinded_str = OpenSSL.malloc(0,
OpenSSL.BN_num_bytes(
signature_blinded))
signature_str = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(signature[0]))
OpenSSL.BN_bn2bin(signature_blinded, signature_blinded_str)
OpenSSL.BN_bn2bin(signature[0], signature_str)
self.assertNotEqual(cast(signature_str, c_char_p).value,
cast(signature_blinded_str, c_char_p).value)
self.assertNotEqual(signature, signature_blinded)
# (5) Verification
verifier_obj = ECCBlind(pubkey=signer_obj.pubkey)
verifier_obj = ECCBlind(pubkey=signer_obj.pubkey())
self.assertTrue(verifier_obj.verify(msg, signature))
# Serialization and deserialisation
pk = signer_obj.serialize()
pko = ECCBlind.deserialize(pk)
self.assertTrue(pko.verify(msg, signature))
def test_is_odd(self):
"""Test our implementation of BN_is_odd"""
for _ in range(1024):
obj = ECCBlind()
x = OpenSSL.BN_new()
y = OpenSSL.BN_new()
OpenSSL.EC_POINT_get_affine_coordinates(
obj.group, obj.Q, x, y, 0)
self.assertEqual(OpenSSL.BN_is_odd(y),
OpenSSL.BN_is_odd_compatible(y))
def test_serialize_ec_point(self):
"""Test EC point serialization/deserialization"""
for _ in range(1024):
try:
obj = ECCBlind()
obj2 = ECCBlind()
randompoint = obj.Q
serialized = obj._ec_point_serialize(randompoint)
secondpoint = obj2._ec_point_deserialize(serialized)
x0 = OpenSSL.BN_new()
y0 = OpenSSL.BN_new()
OpenSSL.EC_POINT_get_affine_coordinates(obj.group,
randompoint, x0,
y0, obj.ctx)
x1 = OpenSSL.BN_new()
y1 = OpenSSL.BN_new()
OpenSSL.EC_POINT_get_affine_coordinates(obj2.group,
secondpoint, x1,
y1, obj2.ctx)
self.assertEqual(OpenSSL.BN_cmp(y0, y1), 0)
self.assertEqual(OpenSSL.BN_cmp(x0, x1), 0)
self.assertEqual(OpenSSL.EC_POINT_cmp(obj.group, randompoint,
secondpoint, 0), 0)
finally:
OpenSSL.BN_free(x0)
OpenSSL.BN_free(x1)
OpenSSL.BN_free(y0)
OpenSSL.BN_free(y1)
del obj
del obj2
def test_serialize_bn(self):
"""Test Bignum serialization/deserialization"""
for _ in range(1024):
obj = ECCBlind()
obj2 = ECCBlind()
randomnum = obj.d
serialized = obj._bn_serialize(randomnum)
secondnum = obj2._bn_deserialize(serialized)
self.assertEqual(OpenSSL.BN_cmp(randomnum, secondnum), 0)
def test_blind_sig_many(self):
"""Test a lot of blind signatures"""
for _ in range(1024):
self.test_blind_sig()
def test_blind_sig_value(self):
"""Test blind signature value checking"""
signer_obj = ECCBlind(value=5)
point_r = signer_obj.signer_init()
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
msg = os.urandom(64)
msg_blinded = requester_obj.create_signing_request(point_r, msg)
signature_blinded = signer_obj.blind_sign(msg_blinded)
signature = requester_obj.unblind(signature_blinded)
verifier_obj = ECCBlind(pubkey=signer_obj.pubkey())
self.assertFalse(verifier_obj.verify(msg, signature, value=8))
def test_blind_sig_expiration(self):
"""Test blind signature expiration checking"""
signer_obj = ECCBlind(year=2020, month=1)
point_r = signer_obj.signer_init()
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
msg = os.urandom(64)
msg_blinded = requester_obj.create_signing_request(point_r, msg)
signature_blinded = signer_obj.blind_sign(msg_blinded)
signature = requester_obj.unblind(signature_blinded)
verifier_obj = ECCBlind(pubkey=signer_obj.pubkey())
self.assertFalse(verifier_obj.verify(msg, signature))
def test_blind_sig_chain(self):
def test_blind_sig_chain(self): # pylint: disable=too-many-locals
"""Test blind signature chain using a random certifier key and a random message"""
test_levels = 5
value = 1
test_levels = 4
msg = os.urandom(1024)
ca = ECCBlind()
signer_obj = ca
output = bytearray()
for level in range(test_levels):
if not level:
output.extend(ca.pubkey())
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
child_obj = ECCBlind()
point_r = signer_obj.signer_init()
pubkey = child_obj.pubkey()
if level == test_levels - 1:
msg_blinded = requester_obj.create_signing_request(point_r,
msg)
else:
msg_blinded = requester_obj.create_signing_request(point_r,
pubkey)
signature_blinded = signer_obj.blind_sign(msg_blinded)
signature = requester_obj.unblind(signature_blinded)
if level != test_levels - 1:
output.extend(pubkey)
output.extend(signature)
signer_obj = child_obj
verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
self.assertTrue(verifychain.verify(msg=msg, value=1))
def test_blind_sig_chain_wrong_ca(self): # pylint: disable=too-many-locals
"""Test blind signature chain with an unlisted ca"""
test_levels = 4
msg = os.urandom(1024)
chain = ECCBlindChain()
ca = ECCBlind()
fake_ca = ECCBlind()
signer_obj = fake_ca
output = bytearray()
for level in range(test_levels):
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
child_obj = ECCBlind()
if not level:
# unlisted CA, but a syntactically valid pubkey
output.extend(fake_ca.pubkey())
point_r = signer_obj.signer_init()
pubkey = child_obj.pubkey()
if level == test_levels - 1:
msg_blinded = requester_obj.create_signing_request(point_r,
msg)
else:
msg_blinded = requester_obj.create_signing_request(point_r,
pubkey)
signature_blinded = signer_obj.blind_sign(msg_blinded)
signature = requester_obj.unblind(signature_blinded)
if level != test_levels - 1:
output.extend(pubkey)
output.extend(signature)
signer_obj = child_obj
verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
self.assertFalse(verifychain.verify(msg, 1))
def test_blind_sig_chain_wrong_msg(self): # pylint: disable=too-many-locals
"""Test blind signature chain with a fake message"""
test_levels = 4
msg = os.urandom(1024)
fake_msg = os.urandom(1024)
ca = ECCBlind()
signer_obj = ca
signer_pubkey = signer_obj.serialize()
output = bytearray()
for level in range(test_levels):
if level == 0:
metadata = Metadata(exp=int(time.time()) + 100,
value=value).serialize()
requester_obj = ECCBlind(pubkey=signer_obj.pubkey,
metadata=metadata)
if not level:
output.extend(ca.pubkey())
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
child_obj = ECCBlind()
point_r = signer_obj.signer_init()
pubkey = child_obj.pubkey()
if level == test_levels - 1:
msg_blinded = requester_obj.create_signing_request(point_r,
msg)
else:
requester_obj = ECCBlind(pubkey=signer_obj.pubkey)
msg_blinded = requester_obj.create_signing_request(point_r,
pubkey)
signature_blinded = signer_obj.blind_sign(msg_blinded)
signature = requester_obj.unblind(signature_blinded)
if level != test_levels - 1:
output.extend(pubkey)
output.extend(signature)
signer_obj = child_obj
verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
self.assertFalse(verifychain.verify(fake_msg, 1))
def test_blind_sig_chain_wrong_intermediary(self): # pylint: disable=too-many-locals
"""Test blind signature chain using a fake intermediary pubkey"""
test_levels = 4
msg = os.urandom(1024)
wrong_level = 2
ca = ECCBlind()
signer_obj = ca
fake_intermediary = ECCBlind()
output = bytearray()
for level in range(test_levels):
if not level:
output.extend(ca.pubkey())
requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
child_obj = ECCBlind()
point_r = signer_obj.signer_init()
pubkey = child_obj.pubkey()
if level == test_levels - 1:
msg_blinded = requester_obj.create_signing_request(point_r,
msg)
else:
msg_blinded = requester.obj.create_signing_request(point_r,
signer_pubkey)
msg_blinded = requester_obj.create_signing_request(point_r,
pubkey)
signature_blinded = signer_obj.blind_sign(msg_blinded)
signature = requester_obj.unblind(signature_blinded)
chain.add_level(signer_obj.pubkey,
signer_obj.metadata.serialize,
signature)
signer_obj = requester_obj
signer_pubkey = requester_obj.serialize()
sigchain = chain.serialize()
verifychain = ECCBlindChain.deserialize(sigchain)
self.assertTrue(verifychain.verify(msg, value))
if level == wrong_level:
output.extend(fake_intermediary.pubkey())
elif level != test_levels - 1:
output.extend(pubkey)
output.extend(signature)
signer_obj = child_obj
verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
self.assertFalse(verifychain.verify(msg, 1))

54
src/tests/test_openssl.py

@ -0,0 +1,54 @@
"""
Test if OpenSSL is working correctly
"""
import unittest
from pybitmessage.pyelliptic.openssl import OpenSSL
try:
OpenSSL.BN_bn2binpad
have_pad = True
except AttributeError:
have_pad = None
class TestOpenSSL(unittest.TestCase):
"""
Test cases for OpenSSL
"""
def test_is_odd(self):
"""Test BN_is_odd implementation"""
ctx = OpenSSL.BN_CTX_new()
a = OpenSSL.BN_new()
group = OpenSSL.EC_GROUP_new_by_curve_name(
OpenSSL.get_curve("secp256k1"))
OpenSSL.EC_GROUP_get_order(group, a, ctx)
bad = 0
for _ in range(1024):
OpenSSL.BN_rand(a, OpenSSL.BN_num_bits(a), 0, 0)
if not OpenSSL.BN_is_odd(a) == OpenSSL.BN_is_odd_compatible(a):
bad += 1
self.assertEqual(bad, 0)
@unittest.skipUnless(have_pad, 'Skipping OpenSSL pad test')
def test_padding(self):
"""Test an alternatie implementation of bn2binpad"""
ctx = OpenSSL.BN_CTX_new()
a = OpenSSL.BN_new()
n = OpenSSL.BN_new()
group = OpenSSL.EC_GROUP_new_by_curve_name(
OpenSSL.get_curve("secp256k1"))
OpenSSL.EC_GROUP_get_order(group, n, ctx)
bad = 0
for _ in range(1024):
OpenSSL.BN_rand(a, OpenSSL.BN_num_bits(n), 0, 0)
b = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(n))
c = OpenSSL.malloc(0, OpenSSL.BN_num_bytes(a))
OpenSSL.BN_bn2binpad(a, b, OpenSSL.BN_num_bytes(n))
OpenSSL.BN_bn2bin(a, c)
if b.raw != c.raw.rjust(OpenSSL.BN_num_bytes(n), chr(0)):
bad += 1
self.assertEqual(bad, 0)
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