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Diffstat (limited to 'src/model')
| -rwxr-xr-x | src/model/python/sha1.py | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/src/model/python/sha1.py b/src/model/python/sha1.py new file mode 100755 index 0000000..4cb74bd --- /dev/null +++ b/src/model/python/sha1.py @@ -0,0 +1,222 @@ +#!/usr/bin/env python3 +# -*- coding: utf-8 -*- +#======================================================================= +# +# sha1.py +# --------- +# Simple, pure Python model of the SHA-1 function. Used as a +# reference for the HW implementation. The code follows the structure +# of the HW implementation as much as possible. +# +# +# Author: Joachim Strömbergson +# (c) 2014 SUNET +# +# 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 OWNER 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. +# +#======================================================================= + +#------------------------------------------------------------------- +# Python module imports. +#------------------------------------------------------------------- +import sys + + +#------------------------------------------------------------------- +# Constants. +#------------------------------------------------------------------- + + +#------------------------------------------------------------------- +# ChaCha() +#------------------------------------------------------------------- +class SHA1(): + def __init__(self, verbose = 0): + self.verbose = verbose + self.H = [0] * 5 + self.T = 0 + self.a = 0 + self.b = 0 + self.c = 0 + self.d = 0 + self.e = 0 + self.W = [0] * 80 + self.k = 0 + + + def init(self): + self.H = [0x67452301, 0xefcdab89, 0x98badcfe, + 0x10325476, 0xc3d2e1f0] + + + def next(self, block): + self._W_schedule(block) + self._copy_digest() + for i in range(80): + self._sha1_round(i) + self._update_digest() + + + def get_digest(self): + return self.H + + + def _copy_digest(self): + self.a = self.H[0] + self.b = self.H[1] + self.c = self.H[2] + self.d = self.H[3] + self.e = self.H[4] + + + def _update_digest(self): + self.H[0] = (self.H[0] + self.a) & 0xffffffff + self.H[1] = (self.H[1] + self.b) & 0xffffffff + self.H[2] = (self.H[2] + self.c) & 0xffffffff + self.H[3] = (self.H[3] + self.d) & 0xffffffff + self.H[4] = (self.H[4] + self.e) & 0xffffffff + + + def _sha1_round(self, round): + if round <= 19: + self.k = 0x5a827999 + self.f = self._Ch(self.b, self.c, self.d) + + elif 20 <= round <= 39: + self.k = 0x6ed9eba1 + self.f = self._Parity(self.b, self.c, self.d) + + elif 40 <= round <= 59: + self.k = 0x8f1bbcdc + self.f = self._Maj(self.b, self.c, self.d) + + elif 60 <= round <= 79: + self.k = 0xca62c1d6 + self.f = self._Parity(self.b, self.c, self.d) + + if self.verbose: + print("Round %0d" % round) + print("Round input values:") + print("a = 0x%08x, b = 0x%08x, c = 0x%08x" % (self.a, self.b, self.c)) + print("d = 0x%08x, e = 0x%08x" % (self.d, self.e)) + print("f = 0x%08x, k = 0x%08x, w = 0x%08x" % (self.f, self.k, self.W[round])) + + + self.T = (self._rotl32(self.a, 5) + self.f + self.e + self.k + self.W[round]) & 0xffffffff + self.e = self.d + self.d = self.c + self.c = self._rotl32(self.b, 30) + self.b = self.a + self.a = self.T + + if self.verbose: + print("Round output values:") + print("a = 0x%08x, b = 0x%08x, c = 0x%08x" % (self.a, self.b, self.c)) + print("d = 0x%08x, e = 0x%08x" % (self.d, self.e)) + print("") + + + def _W_schedule(self, block): + # Expand the block into 80 words before round operations. + for i in range(80): + if (i < 16): + self.W[i] = block[i] + else: + self.W[i] = self._rotl32((self.W[(i - 3)] ^ self.W[(i - 8)] ^ + self.W[(i - 14)] ^ self.W[(i - 16)]), 1) + if (self.verbose): + print("W after schedule:") + for i in range(80): + print("W[%02d] = 0x%08x" % (i, self.W[i])) + print("") + + + def _Ch(self, x, y, z): + return (x & y) ^ (~x & z) + + + def _Maj(self, x, y, z): + return (x & y) ^ (x & z) ^ (y & z) + + + def _Parity(self, x, y, z): + return (x ^ y ^ z) + + def _rotl32(self, n, r): + return ((n << r) | (n >> (32 - r))) & 0xffffffff + + +def compare_digests(digest, expected): + if (digest != expected): + print("Error:") + print("Got:") + print(digest) + print("Expected:") + print(expected) + else: + print("Test case ok.") + + +#------------------------------------------------------------------- +# main() +# +# If executed tests the ChaCha class using known test vectors. +#------------------------------------------------------------------- +def main(): + print("Testing the SHA-256 Python model.") + print("---------------------------------") + print + + my_sha1 = SHA1(verbose=1); + + # TC1: NIST testcase with message "abc" + TC1_block = [0x61626380, 0x00000000, 0x00000000, 0x00000000, + 0x00000000, 0x00000000, 0x00000000, 0x00000000, + 0x00000000, 0x00000000, 0x00000000, 0x00000000, + 0x00000000, 0x00000000, 0x00000000, 0x00000018] + + TC1_expected = [0xa9993e36, 0x4706816a, 0xba3e2571, + 0x7850c26c, 0x9cd0d89d] + + my_sha1.init() + my_sha1.next(TC1_block) + my_digest = my_sha1.get_digest() + compare_digests(my_digest, TC1_expected) + + + +#------------------------------------------------------------------- +# __name__ +# Python thingy which allows the file to be run standalone as +# well as parsed from within a Python interpreter. +#------------------------------------------------------------------- +if __name__=="__main__": + # Run the main function. + sys.exit(main()) + +#======================================================================= +# EOF sha1.py +#======================================================================= |