278 lines
11 KiB
Python
278 lines
11 KiB
Python
"""
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Test for ECC blind signatures
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"""
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import os
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import unittest
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from hashlib import sha256
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from .common import skip_python3
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skip_python3()
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from pybitmessage.pyelliptic import ECCBlind, ECCBlindChain, OpenSSL
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# pylint: disable=protected-access
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class TestBlindSig(unittest.TestCase):
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"""
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Test case for ECC blind signature
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"""
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def test_blind_sig(self):
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"""Test full sequence using a random certifier key and a random message"""
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# See page 127 of the paper
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# (1) Initialization
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signer_obj = ECCBlind()
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point_r = signer_obj.signer_init()
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self.assertEqual(len(signer_obj.pubkey()), 35)
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# (2) Request
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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# only 64 byte messages are planned to be used in Bitmessage
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msg = os.urandom(64)
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msg_blinded = requester_obj.create_signing_request(point_r, msg)
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self.assertEqual(len(msg_blinded), 32)
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# check
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self.assertNotEqual(sha256(msg).digest(), msg_blinded)
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# (3) Signature Generation
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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assert isinstance(signature_blinded, bytes)
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self.assertEqual(len(signature_blinded), 32)
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# (4) Extraction
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signature = requester_obj.unblind(signature_blinded)
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assert isinstance(signature, bytes)
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self.assertEqual(len(signature), 65)
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self.assertNotEqual(signature, signature_blinded)
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# (5) Verification
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verifier_obj = ECCBlind(pubkey=signer_obj.pubkey())
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self.assertTrue(verifier_obj.verify(msg, signature))
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def test_is_odd(self):
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"""Test our implementation of BN_is_odd"""
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for _ in range(1024):
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obj = ECCBlind()
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x = OpenSSL.BN_new()
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y = OpenSSL.BN_new()
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OpenSSL.EC_POINT_get_affine_coordinates(
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obj.group, obj.Q, x, y, 0)
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self.assertEqual(OpenSSL.BN_is_odd(y),
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OpenSSL.BN_is_odd_compatible(y))
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def test_serialize_ec_point(self):
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"""Test EC point serialization/deserialization"""
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for _ in range(1024):
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try:
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obj = ECCBlind()
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obj2 = ECCBlind()
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randompoint = obj.Q
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serialized = obj._ec_point_serialize(randompoint)
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secondpoint = obj2._ec_point_deserialize(serialized)
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x0 = OpenSSL.BN_new()
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y0 = OpenSSL.BN_new()
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OpenSSL.EC_POINT_get_affine_coordinates(obj.group,
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randompoint, x0,
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y0, obj.ctx)
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x1 = OpenSSL.BN_new()
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y1 = OpenSSL.BN_new()
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OpenSSL.EC_POINT_get_affine_coordinates(obj2.group,
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secondpoint, x1,
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y1, obj2.ctx)
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self.assertEqual(OpenSSL.BN_cmp(y0, y1), 0)
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self.assertEqual(OpenSSL.BN_cmp(x0, x1), 0)
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self.assertEqual(OpenSSL.EC_POINT_cmp(obj.group, randompoint,
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secondpoint, 0), 0)
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finally:
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OpenSSL.BN_free(x0)
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OpenSSL.BN_free(x1)
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OpenSSL.BN_free(y0)
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OpenSSL.BN_free(y1)
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del obj
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del obj2
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def test_serialize_bn(self):
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"""Test Bignum serialization/deserialization"""
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for _ in range(1024):
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obj = ECCBlind()
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obj2 = ECCBlind()
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randomnum = obj.d
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serialized = obj._bn_serialize(randomnum)
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secondnum = obj2._bn_deserialize(serialized)
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self.assertEqual(OpenSSL.BN_cmp(randomnum, secondnum), 0)
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def test_blind_sig_many(self):
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"""Test a lot of blind signatures"""
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for _ in range(1024):
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self.test_blind_sig()
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def test_blind_sig_value(self):
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"""Test blind signature value checking"""
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signer_obj = ECCBlind(value=5)
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point_r = signer_obj.signer_init()
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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msg = os.urandom(64)
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msg_blinded = requester_obj.create_signing_request(point_r, msg)
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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signature = requester_obj.unblind(signature_blinded)
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verifier_obj = ECCBlind(pubkey=signer_obj.pubkey())
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self.assertFalse(verifier_obj.verify(msg, signature, value=8))
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def test_blind_sig_expiration(self):
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"""Test blind signature expiration checking"""
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signer_obj = ECCBlind(year=2020, month=1)
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point_r = signer_obj.signer_init()
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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msg = os.urandom(64)
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msg_blinded = requester_obj.create_signing_request(point_r, msg)
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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signature = requester_obj.unblind(signature_blinded)
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verifier_obj = ECCBlind(pubkey=signer_obj.pubkey())
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self.assertFalse(verifier_obj.verify(msg, signature))
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def test_blind_sig_chain(self): # pylint: disable=too-many-locals
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"""Test blind signature chain using a random certifier key and a random message"""
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test_levels = 4
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msg = os.urandom(1024)
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ca = ECCBlind()
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signer_obj = ca
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output = bytearray()
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for level in range(test_levels):
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if not level:
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output.extend(ca.pubkey())
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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child_obj = ECCBlind()
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point_r = signer_obj.signer_init()
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pubkey = child_obj.pubkey()
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if level == test_levels - 1:
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msg_blinded = requester_obj.create_signing_request(point_r,
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msg)
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else:
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msg_blinded = requester_obj.create_signing_request(point_r,
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pubkey)
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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signature = requester_obj.unblind(signature_blinded)
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if level != test_levels - 1:
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output.extend(pubkey)
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output.extend(signature)
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signer_obj = child_obj
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verifychain = ECCBlindChain(ca=ca.pubkey(), chain=bytes(output))
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self.assertTrue(verifychain.verify(msg=msg, value=1))
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def test_blind_sig_chain_wrong_ca(self): # pylint: disable=too-many-locals
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"""Test blind signature chain with an unlisted ca"""
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test_levels = 4
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msg = os.urandom(1024)
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ca = ECCBlind()
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fake_ca = ECCBlind()
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signer_obj = fake_ca
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output = bytearray()
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for level in range(test_levels):
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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child_obj = ECCBlind()
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if not level:
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# unlisted CA, but a syntactically valid pubkey
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output.extend(fake_ca.pubkey())
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point_r = signer_obj.signer_init()
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pubkey = child_obj.pubkey()
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if level == test_levels - 1:
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msg_blinded = requester_obj.create_signing_request(point_r,
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msg)
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else:
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msg_blinded = requester_obj.create_signing_request(point_r,
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pubkey)
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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signature = requester_obj.unblind(signature_blinded)
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if level != test_levels - 1:
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output.extend(pubkey)
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output.extend(signature)
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signer_obj = child_obj
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verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
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self.assertFalse(verifychain.verify(msg, 1))
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def test_blind_sig_chain_wrong_msg(self): # pylint: disable=too-many-locals
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"""Test blind signature chain with a fake message"""
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test_levels = 4
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msg = os.urandom(1024)
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fake_msg = os.urandom(1024)
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ca = ECCBlind()
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signer_obj = ca
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output = bytearray()
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for level in range(test_levels):
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if not level:
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output.extend(ca.pubkey())
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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child_obj = ECCBlind()
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point_r = signer_obj.signer_init()
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pubkey = child_obj.pubkey()
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if level == test_levels - 1:
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msg_blinded = requester_obj.create_signing_request(point_r,
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msg)
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else:
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msg_blinded = requester_obj.create_signing_request(point_r,
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pubkey)
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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signature = requester_obj.unblind(signature_blinded)
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if level != test_levels - 1:
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output.extend(pubkey)
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output.extend(signature)
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signer_obj = child_obj
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verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
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self.assertFalse(verifychain.verify(fake_msg, 1))
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def test_blind_sig_chain_wrong_intermediary(self): # pylint: disable=too-many-locals
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"""Test blind signature chain using a fake intermediary pubkey"""
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test_levels = 4
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msg = os.urandom(1024)
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wrong_level = 2
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ca = ECCBlind()
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signer_obj = ca
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fake_intermediary = ECCBlind()
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output = bytearray()
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for level in range(test_levels):
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if not level:
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output.extend(ca.pubkey())
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requester_obj = ECCBlind(pubkey=signer_obj.pubkey())
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child_obj = ECCBlind()
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point_r = signer_obj.signer_init()
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pubkey = child_obj.pubkey()
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if level == test_levels - 1:
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msg_blinded = requester_obj.create_signing_request(point_r,
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msg)
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else:
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msg_blinded = requester_obj.create_signing_request(point_r,
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pubkey)
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signature_blinded = signer_obj.blind_sign(msg_blinded)
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signature = requester_obj.unblind(signature_blinded)
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if level == wrong_level:
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output.extend(fake_intermediary.pubkey())
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elif level != test_levels - 1:
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output.extend(pubkey)
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output.extend(signature)
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signer_obj = child_obj
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verifychain = ECCBlindChain(ca=ca.pubkey(), chain=str(output))
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self.assertFalse(verifychain.verify(msg, 1))
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