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-rwxr-xr-xsrc/model/python/sha1.py222
1 files changed, 222 insertions, 0 deletions
diff --git a/src/model/python/sha1.py b/src/model/python/sha1.py
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+#!/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
+#=======================================================================