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Diffstat (limited to 'lib/Crypto/SelfTest/Math/test_modexp.py')
| -rw-r--r-- | lib/Crypto/SelfTest/Math/test_modexp.py | 201 |
1 files changed, 201 insertions, 0 deletions
diff --git a/lib/Crypto/SelfTest/Math/test_modexp.py b/lib/Crypto/SelfTest/Math/test_modexp.py new file mode 100644 index 0000000..b9eb869 --- /dev/null +++ b/lib/Crypto/SelfTest/Math/test_modexp.py @@ -0,0 +1,201 @@ +# +# SelfTest/Math/test_modexp.py: Self-test for module exponentiation +# +# =================================================================== +# +# Copyright (c) 2017, Helder Eijs <helderijs@gmail.com> +# All rights reserved. +# +# Redistribution and use in source and binary forms, with or without +# modification, are permitted provided that the following conditions +# are met: +# +# 1. Redistributions of source code must retain the above copyright +# notice, this list of conditions and the following disclaimer. +# 2. Redistributions in binary form must reproduce the above copyright +# notice, this list of conditions and the following disclaimer in +# the documentation and/or other materials provided with the +# distribution. +# +# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS +# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT +# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS +# FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE +# COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, +# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, +# BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; +# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER +# CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN +# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE +# POSSIBILITY OF SUCH DAMAGE. +# =================================================================== + +"""Self-test for the custom module exponentiation""" + +import unittest + +from Crypto.SelfTest.st_common import list_test_cases + +from Crypto.Util.number import long_to_bytes, bytes_to_long + +from Crypto.Util.py3compat import * + +from Crypto.Util._raw_api import (load_pycryptodome_raw_lib, + create_string_buffer, + get_raw_buffer, + c_size_t, + c_ulonglong) + +from Crypto.Hash import SHAKE128 +from Crypto.Math.Numbers import Integer +from Crypto.Math._IntegerCustom import _raw_montgomery + +from Crypto.Random.random import StrongRandom + + +def create_rng(tag): + rng = StrongRandom(SHAKE128.new(data=tag)) + return rng + +class ExceptionModulus(ValueError): + pass + +def monty_pow(base, exp, modulus): + max_len = len(long_to_bytes(max(base, exp, modulus))) + + base_b, exp_b, modulus_b = [ long_to_bytes(x, max_len) for x in + (base, exp, modulus) ] + + out = create_string_buffer(max_len) + error = _raw_montgomery.monty_pow( + out, + base_b, + exp_b, + modulus_b, + c_size_t(max_len), + c_ulonglong(32) + ) + + if error == 17: + raise ExceptionModulus() + if error: + raise ValueError("monty_pow failed with error: %d" % error) + + result = bytes_to_long(get_raw_buffer(out)) + return result + +exponent1 = 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 +modulus1 = 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 + + +class TestModExp(unittest.TestCase): + + def test_small(self): + self.assertEqual(1, monty_pow(11,12,19)) + + def test_large_1(self): + base = 0xfffffffffffffffffffffffffffffffffffffffffffffffffff + expected = pow(base, exponent1, modulus1) + result = monty_pow(base, exponent1, modulus1) + self.assertEqual(result, expected) + + def test_zero_exp(self): + base = 0xfffffffffffffffffffffffffffffffffffffffffffffffffff + result = monty_pow(base, 0, modulus1) + self.assertEqual(result, 1) + + def test_zero_base(self): + result = monty_pow(0, exponent1, modulus1) + self.assertEqual(result, 0) + + def test_zero_modulus(self): + base = 0xfffffffffffffffffffffffffffffffffffffffffffffffff + self.assertRaises(ExceptionModulus, monty_pow, base, exponent1, 0) + self.assertRaises(ExceptionModulus, monty_pow, 0, 0, 0) + + def test_larger_exponent(self): + base = modulus1 - 0xFFFFFFF + expected = pow(base, modulus1<<64, modulus1) + result = monty_pow(base, modulus1<<64, modulus1) + self.assertEqual(result, expected) + + def test_even_modulus(self): + base = modulus1 >> 4 + self.assertRaises(ExceptionModulus, monty_pow, base, exponent1, modulus1-1) + + def test_several_lengths(self): + prng = SHAKE128.new().update(b('Test')) + for length in range(1, 100): + modulus2 = Integer.from_bytes(prng.read(length)) | 1 + base = Integer.from_bytes(prng.read(length)) % modulus2 + exponent2 = Integer.from_bytes(prng.read(length)) + + expected = pow(base, exponent2, modulus2) + result = monty_pow(base, exponent2, modulus2) + self.assertEqual(result, expected) + + def test_variable_exponent(self): + prng = create_rng(b('Test variable exponent')) + for i in range(20): + for j in range(7): + modulus = prng.getrandbits(8*30) | 1 + base = prng.getrandbits(8*30) % modulus + exponent = prng.getrandbits(i*8+j) + + expected = pow(base, exponent, modulus) + result = monty_pow(base, exponent, modulus) + self.assertEqual(result, expected) + + exponent ^= (1 << (i*8+j)) - 1 + + expected = pow(base, exponent, modulus) + result = monty_pow(base, exponent, modulus) + self.assertEqual(result, expected) + + def test_stress_63(self): + prng = create_rng(b('Test 63')) + length = 63 + for _ in range(2000): + modulus = prng.getrandbits(8*length) | 1 + base = prng.getrandbits(8*length) % modulus + exponent = prng.getrandbits(8*length) + + expected = pow(base, exponent, modulus) + result = monty_pow(base, exponent, modulus) + self.assertEqual(result, expected) + + def test_stress_64(self): + prng = create_rng(b('Test 64')) + length = 64 + for _ in range(2000): + modulus = prng.getrandbits(8*length) | 1 + base = prng.getrandbits(8*length) % modulus + exponent = prng.getrandbits(8*length) + + expected = pow(base, exponent, modulus) + result = monty_pow(base, exponent, modulus) + self.assertEqual(result, expected) + + def test_stress_65(self): + prng = create_rng(b('Test 65')) + length = 65 + for _ in range(2000): + modulus = prng.getrandbits(8*length) | 1 + base = prng.getrandbits(8*length) % modulus + exponent = prng.getrandbits(8*length) + + expected = pow(base, exponent, modulus) + result = monty_pow(base, exponent, modulus) + self.assertEqual(result, expected) + + +def get_tests(config={}): + tests = [] + tests += list_test_cases(TestModExp) + return tests + + +if __name__ == '__main__': + suite = lambda: unittest.TestSuite(get_tests()) + unittest.main(defaultTest='suite') |