From 964b1ec662ed439b0f56c8bc232a987fa20cd0e1 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Joachim=20Stro=CC=88mbergson?= Date: Thu, 27 Nov 2014 15:50:21 +0100 Subject: Adding Python models for AES as well as key expansion and rcon. --- src/model/python/aes.py | 1057 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 1057 insertions(+) create mode 100755 src/model/python/aes.py (limited to 'src/model/python/aes.py') diff --git a/src/model/python/aes.py b/src/model/python/aes.py new file mode 100755 index 0000000..582f2b4 --- /dev/null +++ b/src/model/python/aes.py @@ -0,0 +1,1057 @@ +#!/usr/bin/env python3 +# -*- coding: utf-8 -*- +#======================================================================= +# +# aes.py +# ------ +# Simple, pure Python, word based model of the AES cipher with +# support for 128 and 256 bit keys. +# +# +# Author: Joachim Strombergson +# Copyright (c) 2014, SUNET +# 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 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. +#------------------------------------------------------------------- +VERBOSE = True +DUMP_VARS = True + +AES_128_ROUNDS = 10 +AES_256_ROUNDS = 14 + + +sbox = [0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, + 0x30, 0x01, 0x67, 0x2b, 0xfe, 0xd7, 0xab, 0x76, + 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, 0x47, 0xf0, + 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, + 0xb7, 0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, + 0x34, 0xa5, 0xe5, 0xf1, 0x71, 0xd8, 0x31, 0x15, + 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, 0x9a, + 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, + 0x09, 0x83, 0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, + 0x52, 0x3b, 0xd6, 0xb3, 0x29, 0xe3, 0x2f, 0x84, + 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, + 0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, + 0xd0, 0xef, 0xaa, 0xfb, 0x43, 0x4d, 0x33, 0x85, + 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, 0x9f, 0xa8, + 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, + 0xbc, 0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, + 0xcd, 0x0c, 0x13, 0xec, 0x5f, 0x97, 0x44, 0x17, + 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, 0x73, + 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, + 0x46, 0xee, 0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, + 0xe0, 0x32, 0x3a, 0x0a, 0x49, 0x06, 0x24, 0x5c, + 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, + 0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, + 0x6c, 0x56, 0xf4, 0xea, 0x65, 0x7a, 0xae, 0x08, + 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, 0xb4, 0xc6, + 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, + 0x70, 0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, + 0x61, 0x35, 0x57, 0xb9, 0x86, 0xc1, 0x1d, 0x9e, + 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, 0x94, + 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, + 0x8c, 0xa1, 0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, + 0x41, 0x99, 0x2d, 0x0f, 0xb0, 0x54, 0xbb, 0x16] + + +inv_sbox = [0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, + 0xbf, 0x40, 0xa3, 0x9e, 0x81, 0xf3, 0xd7, 0xfb, + 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, 0xff, 0x87, + 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, + 0x54, 0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, + 0xee, 0x4c, 0x95, 0x0b, 0x42, 0xfa, 0xc3, 0x4e, + 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, 0xb2, + 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, + 0x72, 0xf8, 0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, + 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, 0x65, 0xb6, 0x92, + 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, + 0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, + 0x90, 0xd8, 0xab, 0x00, 0x8c, 0xbc, 0xd3, 0x0a, + 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, 0x45, 0x06, + 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, + 0xc1, 0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, + 0x3a, 0x91, 0x11, 0x41, 0x4f, 0x67, 0xdc, 0xea, + 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, 0x73, + 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, + 0xe2, 0xf9, 0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, + 0x47, 0xf1, 0x1a, 0x71, 0x1d, 0x29, 0xc5, 0x89, + 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, + 0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, + 0x9a, 0xdb, 0xc0, 0xfe, 0x78, 0xcd, 0x5a, 0xf4, + 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, 0xc7, 0x31, + 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, + 0x60, 0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, + 0x2d, 0xe5, 0x7a, 0x9f, 0x93, 0xc9, 0x9c, 0xef, + 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, 0xb0, + 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, + 0x17, 0x2b, 0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, + 0xe1, 0x69, 0x14, 0x63, 0x55, 0x21, 0x0c, 0x7d] + + +#------------------------------------------------------------------- +# print_bytekeys() +# +# Print a set of round keys given as an array of bytes. +#------------------------------------------------------------------- +def print_bytekeys(keys): + i = 0 + print("Number of round keys: %d" % (int(len(keys) / 16))) + while i < (len(keys) - 1): + for j in range(16): + print("0x%02x " % keys[i + j], end="") + print("") + i += 16 + +#------------------------------------------------------------------- +# print_block() +# +# Print the given block as four 32 bit words. +#------------------------------------------------------------------- +def print_block(block): + (w0, w1, w2, w3) = block + print("0x%08x, 0x%08x, 0x%08x, 0x%08x" % (w0, w1, w2, w3)) + + +#------------------------------------------------------------------- +# print_key() +# +# Print the given key as on or two sets of four 32 bit words. +#------------------------------------------------------------------- +def print_key(key): + if len(key) == 8: + (k0, k1, k2, k3, k4, k5, k6, k7) = key + print_block((k0, k1, k2, k3)) + print_block((k4, k5, k6, k7)) + else: + print_block(key) + + +#------------------------------------------------------------------- +# b2w() +# +# Create a word from the given bytes. +#------------------------------------------------------------------- +def b2w(b0, b1, b2, b3): + return (b0 << 24) + (b1 << 16) + (b2 << 8) + b3 + + +#------------------------------------------------------------------- +# w2b() +# +# Extracts the bytes in a word. +#------------------------------------------------------------------- +def w2b(w): + b0 = w >> 24 + b1 = w >> 16 & 0xff + b2 = w >> 8 & 0xff + b3 = w & 0xff + + return (b0, b1, b2, b3) + + +#------------------------------------------------------------------- +# gm2() +# +# The specific Galois Multiplication by two for a given byte. +#------------------------------------------------------------------- +def gm2(b): + return ((b << 1) ^ (0x1b & ((b >> 7) * 0xff))) & 0xff + + +#------------------------------------------------------------------- +# gm3() +# +# The specific Galois Multiplication by three for a given byte. +#------------------------------------------------------------------- +def gm3(b): + return gm2(b) ^ b + + +#------------------------------------------------------------------- +# gm4() +# +# The specific Galois Multiplication by four for a given byte. +#------------------------------------------------------------------- +def gm4(b): + return gm2(gm2(b)) + + +#------------------------------------------------------------------- +# gm8() +# +# The specific Galois Multiplication by eight for a given byte. +#------------------------------------------------------------------- +def gm8(b): + return gm2(gm4(b)) + + +#------------------------------------------------------------------- +# gm09() +# +# The specific Galois Multiplication by nine for a given byte. +#------------------------------------------------------------------- +def gm09(b): + return gm8(b) ^ b + + +#------------------------------------------------------------------- +# gm11() +# +# The specific Galois Multiplication by 11 for a given byte. +#------------------------------------------------------------------- +def gm11(b): + return gm8(b) ^ gm2(b) ^ b + + +#------------------------------------------------------------------- +# gm13() +# +# The specific Galois Multiplication by 13 for a given byte. +#------------------------------------------------------------------- +def gm13(b): + return gm8(b) ^ gm4(b) ^ b + + +#------------------------------------------------------------------- +# gm14() +# +# The specific Galois Multiplication by 14 for a given byte. +#------------------------------------------------------------------- +def gm14(b): + return gm8(b) ^ gm4(b) ^ gm2(b) + + +#------------------------------------------------------------------- +# substw() +# +# Returns a 32-bit word in which each of the bytes in the +# given 32-bit word has been used as lookup into the AES S-box. +#------------------------------------------------------------------- +def substw(w): + (b0, b1, b2, b3) = w2b(w) + + s0 = sbox[b0] + s1 = sbox[b1] + s2 = sbox[b2] + s3 = sbox[b3] + + res = b2w(s0, s1, s2, s3) + + if VERBOSE: + print("Inside substw:") + print("b0 = 0x%02x, b1 = 0x%02x, b2 = 0x%02x, b3 = 0x%02x" % + (b0, b1, b2, b3)) + print("s0 = 0x%02x, s1 = 0x%02x, s2 = 0x%02x, s3 = 0x%02x" % + (s0, s1, s2, s3)) + print("res = 0x%08x" % (res)) + + return res + + +#------------------------------------------------------------------- +# inv_substw() +# +# Returns a 32-bit word in which each of the bytes in the +# given 32-bit word has been used as lookup into +# the inverse AES S-box. +#------------------------------------------------------------------- +def inv_substw(w): + (b0, b1, b2, b3) = w2b(w) + + s0 = inv_sbox[b0] + s1 = inv_sbox[b1] + s2 = inv_sbox[b2] + s3 = inv_sbox[b3] + + res = b2w(s0, s1, s2, s3) + + if VERBOSE: + print("Inside inv_substw:") + print("b0 = 0x%02x, b1 = 0x%02x, b2 = 0x%02x, b3 = 0x%02x" % + (b0, b1, b2, b3)) + print("s0 = 0x%02x, s1 = 0x%02x, s2 = 0x%02x, s3 = 0x%02x" % + (s0, s1, s2, s3)) + print("res = 0x%08x" % (res)) + + return res + + +#------------------------------------------------------------------- +# rolx() +# +# Rotate the given 32 bit word x bits left. +#------------------------------------------------------------------- +def rolx(w, x): + return ((w << x) | (w >> (32 - x))) & 0xffffffff + + +#------------------------------------------------------------------- +# next_128bit_key() +# +# Generate the next four key words for aes-128 based on given +# rcon and previous key words. +#------------------------------------------------------------------- +def next_128bit_key(prev_key, rcon): + (w0, w1, w2, w3) = prev_key + + rol = rolx(w3, 8) + subst = substw(rol) + t = subst ^ (rcon << 24) + + k0 = w0 ^ t + k1 = w1 ^ w0 ^ t + k2 = w2 ^ w1 ^ w0 ^ t + k3 = w3 ^ w2 ^ w1 ^ w0 ^ t + + if VERBOSE: + print("Inside next 128bit key:") + print("w0 = 0x%08x, w1 = 0x%08x, w2 = 0x%08x, w3 = 0x%08x" % + (w0, w1, w2, w3)) + print("rol = 0x%08x, subst = 0x%08x, rcon = 0x%02x, t = 0x%08x" % + (rol, subst, rcon, t)) + print("k0 = 0x%08x, k1 = 0x%08x, k2 = 0x%08x, k3 = 0x%08x" % + (k0, k1, k2, k3)) + + return (k0, k1, k2, k3) + + +#------------------------------------------------------------------- +# key_gen128() +# +# Generating the keys for 128 bit keys. +#------------------------------------------------------------------- +def key_gen128(key): + print("Doing the 128 bit key expansion") + + round_keys = [] + + round_keys.append(key) + + for i in range(10): + round_keys.append(next_128bit_key(round_keys[i], get_rcon(i + 1))) + + if VERBOSE: + print("Input key:") + print_block(key) + print("") + + print("Generated keys:") + for k in round_keys: + print_block(k) + print("") + + return round_keys + + +#------------------------------------------------------------------- +# next_256bit_key_a() +# +# Generate the next four key words for aes-256 using algorithm A +# based on given rcon and the previous two keys. +#------------------------------------------------------------------- +def next_256it_key_a(key0, key1, rcon): + (w0, w1, w2, w3) = key0 + (w4, w5, w6, w7) = key1 + + sw = substw(rolx(w7, 8)) + rw = (rcon << 24) + t = sw ^ rw + + k0 = w0 ^ t + k1 = w1 ^ w0 ^ t + k2 = w2 ^ w1 ^ w0 ^ t + k3 = w3 ^ w2 ^ w1 ^ w0 ^ t + + if (DUMP_VARS): + print("next_256bit_key_a:") + print("w0 = 0x%08x, w0 = 0x%08x, w0 = 0x%08x, w0 = 0x%08x" % (w0, w1, w2, w3)) + print("w4 = 0x%08x, w5 = 0x%08x, w6 = 0x%08x, w7 = 0x%08x" % (w4, w5, w6, w7)) + print("t = 0x%08x, sw = 0x%08x, rw = 0x%08x" % (t, sw, rw)) + print("k0 = 0x%08x, k0 = 0x%08x, k0 = 0x%08x, k0 = 0x%08x" % (k0, k1, k2, k3)) + print("") + + return (k0, k1, k2, k3) + + +#------------------------------------------------------------------- +# next_256bit_key_b() +# +# Generate the next four key words for aes-256 using algorithm B +# based on given previous eight keywords. +#------------------------------------------------------------------- +def next_256it_key_b(key0, key1): + (w0, w1, w2, w3) = key0 + (w4, w5, w6, w7) = key1 + + t = substw(w7) + + k0 = w0 ^ t + k1 = w1 ^ w0 ^ t + k2 = w2 ^ w1 ^ w0 ^ t + k3 = w3 ^ w2 ^ w1 ^ w0 ^ t + + if (DUMP_VARS): + print("next_256bit_key_b:") + print("w0 = 0x%08x, w0 = 0x%08x, w0 = 0x%08x, w0 = 0x%08x" % (w0, w1, w2, w3)) + print("w4 = 0x%08x, w5 = 0x%08x, w6 = 0x%08x, w7 = 0x%08x" % (w4, w5, w6, w7)) + print("t = 0x%08x" % (t)) + print("k0 = 0x%08x, k0 = 0x%08x, k0 = 0x%08x, k0 = 0x%08x" % (k0, k1, k2, k3)) + print("") + + return (k0, k1, k2, k3) + + +#------------------------------------------------------------------- +# key_gen256() +# +# Generating the keys for 256 bit keys. +#------------------------------------------------------------------- +def key_gen256(key): + round_keys = [] + (k0, k1, k2, k3, k4, k5, k6, k7) = key + + round_keys.append((k0, k1, k2, k3)) + round_keys.append((k4, k5, k6, k7)) + + j = 1 + for i in range(0, (AES_256_ROUNDS - 2), 2): + k = next_256it_key_a(round_keys[i], round_keys[i + 1], get_rcon(j)) + round_keys.append(k) + k = next_256it_key_b(round_keys[i + 1], round_keys[i + 2]) + round_keys.append(k) + j += 1 + + # One final key needs to be generated. + k = next_256it_key_a(round_keys[12], round_keys[13], get_rcon(7)) + round_keys.append(k) + + if VERBOSE: + print("Input key:") + print_block((k0, k1, k2, k3)) + print_block((k4, k5, k6, k7)) + print("") + + print("Generated keys:") + for k in round_keys: + print_block(k) + print("") + + return round_keys + + +#------------------------------------------------------------------- +# get_rcon() +# +# Function implementation of rcon. Calculates rcon for a +# given round. This could be implemented as an iterator. +#------------------------------------------------------------------- +def get_rcon(round): + rcon = 0x8d + + for i in range(0, round): + rcon = ((rcon << 1) ^ (0x11b & - (rcon >> 7))) & 0xff + + return rcon + + +#------------------------------------------------------------------- +# addroundkey() +# +# AES AddRoundKey block operation. +# Perform XOR combination of the given block and the given key. +#------------------------------------------------------------------- +def addroundkey(key, block): + (w0, w1, w2, w3) = block + (k0, k1, k2, k3) = key + + res_block = (w0 ^ k0, w1 ^ k1, w2 ^ k2, w3 ^ k3) + + if VERBOSE: + print("AddRoundKey key, block in and block out:") + print_block(key) + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# mixw() +# +# Perform bit mixing of the given words. +#------------------------------------------------------------------- +def mixw(w): + (b0, b1, b2, b3) = w2b(w) + + mb0 = gm2(b0) ^ gm3(b1) ^ b2 ^ b3 + mb1 = b0 ^ gm2(b1) ^ gm3(b2) ^ b3 + mb2 = b0 ^ b1 ^ gm2(b2) ^ gm3(b3) + mb3 = gm3(b0) ^ b1 ^ b2 ^ gm2(b3) + + return b2w(mb0, mb1, mb2, mb3) + + +#------------------------------------------------------------------- +# mixcolumns() +# +# AES MixColumns on the given block. +#------------------------------------------------------------------- +def mixcolumns(block): + (c0, c1, c2, c3) = block + + mc0 = mixw(c0) + mc1 = mixw(c1) + mc2 = mixw(c2) + mc3 = mixw(c3) + + res_block = (mc0, mc1, mc2, mc3) + + if VERBOSE: + print("MixColumns block in and block out:") + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# subbytes() +# +# AES SubBytes operation on the given block. +#------------------------------------------------------------------- +def subbytes(block): + (w0, w1, w2, w3) = block + + res_block = (substw(w0), substw(w1), substw(w2), substw(w3)) + + if VERBOSE: + print("SubBytes block in and block out:") + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# shiftrows() +# +# AES ShiftRows block operation. +#------------------------------------------------------------------- +def shiftrows(block): + (w0, w1, w2, w3) = block + + c0 = w2b(w0) + c1 = w2b(w1) + c2 = w2b(w2) + c3 = w2b(w3) + + ws0 = b2w(c0[0], c1[1], c2[2], c3[3]) + ws1 = b2w(c1[0], c2[1], c3[2], c0[3]) + ws2 = b2w(c2[0], c3[1], c0[2], c1[3]) + ws3 = b2w(c3[0], c0[1], c1[2], c2[3]) + + res_block = (ws0, ws1, ws2, ws3) + + if VERBOSE: + print("ShiftRows block in and block out:") + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# aes_encipher() +# +# Perform AES encipher operation for the given block using the +# given key length. +#------------------------------------------------------------------- +def aes_encipher_block(key, block): + tmp_block = block[:] + + # Get round keys based on the given key. + if len(key) == 4: + round_keys = key_gen128(key) + num_rounds = AES_128_ROUNDS + else: + round_keys = key_gen256(key) + num_rounds = AES_256_ROUNDS + + # Init round + print(" Initial AddRoundKeys round.") + tmp_block4 = addroundkey(round_keys[0], block) + + # Main rounds + for i in range(1 , (num_rounds)): + print("") + print(" Round %02d" % i) + print(" ---------") + + tmp_block1 = subbytes(tmp_block4) + tmp_block2 = shiftrows(tmp_block1) + tmp_block3 = mixcolumns(tmp_block2) + tmp_block4 = addroundkey(round_keys[i], tmp_block3) + + + # Final round + print(" Final round.") + tmp_block1 = subbytes(tmp_block4) + tmp_block2 = shiftrows(tmp_block1) + tmp_block3 = addroundkey(round_keys[num_rounds], tmp_block2) + + return tmp_block3 + + +#------------------------------------------------------------------- +# inv_mixw() +# +# Perform inverse bit mixing of the given words. +#------------------------------------------------------------------- +def inv_mixw(w): + (b0, b1, b2, b3) = w2b(w) + + mb0 = gm14(b0) ^ gm11(b1) ^ gm13(b2) ^ gm09(b3) + mb1 = gm09(b0) ^ gm14(b1) ^ gm11(b2) ^ gm13(b3) + mb2 = gm13(b0) ^ gm09(b1) ^ gm14(b2) ^ gm11(b3) + mb3 = gm11(b0) ^ gm13(b1) ^ gm09(b2) ^ gm14(b3) + + return b2w(mb0, mb1, mb2, mb3) + + +#------------------------------------------------------------------- +# inv_mixcolumns() +# +# AES Inverse MixColumns on the given block. +#------------------------------------------------------------------- +def inv_mixcolumns(block): + (c0, c1, c2, c3) = block + + mc0 = inv_mixw(c0) + mc1 = inv_mixw(c1) + mc2 = inv_mixw(c2) + mc3 = inv_mixw(c3) + + res_block = (mc0, mc1, mc2, mc3) + + if VERBOSE: + print("Inverse MixColumns block in and block out:") + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# inv_shiftrows() +# +# AES inverse ShiftRows block operation. +#------------------------------------------------------------------- +def inv_shiftrows(block): + (w0, w1, w2, w3) = block + + c0 = w2b(w0) + c1 = w2b(w1) + c2 = w2b(w2) + c3 = w2b(w3) + + ws0 = b2w(c0[0], c3[1], c2[2], c1[3]) + ws1 = b2w(c1[0], c0[1], c3[2], c2[3]) + ws2 = b2w(c2[0], c1[1], c0[2], c3[3]) + ws3 = b2w(c3[0], c2[1], c1[2], c0[3]) + + res_block = (ws0, ws1, ws2, ws3) + + if VERBOSE: + print("Inverse ShiftRows block in and block out:") + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# inv_subbytes() +# +# AES inverse SubBytes operation on the given block. +#------------------------------------------------------------------- +def inv_subbytes(block): + (w0, w1, w2, w3) = block + + res_block = (inv_substw(w0), inv_substw(w1), inv_substw(w2), inv_substw(w3)) + + if VERBOSE: + print("Inverse SubBytes block in and block out:") + print_block(block) + print_block(res_block) + print("") + + return res_block + + +#------------------------------------------------------------------- +# aes_decipher() +# +# Perform AES decipher operation for the given block +# using the given key length. +#------------------------------------------------------------------- +def aes_decipher_block(key, block): + tmp_block = block[:] + + # Get round keys based on the given key. + if len(key) == 4: + round_keys = key_gen128(key) + num_rounds = AES_128_ROUNDS + else: + round_keys = key_gen256(key) + num_rounds = AES_256_ROUNDS + + # Initial round + print(" Initial, partial round.") + tmp_block1 = addroundkey(round_keys[len(round_keys) - 1], tmp_block) + tmp_block2 = inv_shiftrows(tmp_block1) + tmp_block4 = inv_subbytes(tmp_block2) + + # Main rounds + for i in range(1 , (num_rounds)): + print("") + print(" Round %02d" % i) + print(" ---------") + + tmp_block1 = addroundkey(round_keys[(len(round_keys) - i - 1)], tmp_block4) + tmp_block2 = inv_mixcolumns(tmp_block1) + tmp_block3 = inv_shiftrows(tmp_block2) + tmp_block4 = inv_subbytes(tmp_block3) + + # Final round + print(" Final AddRoundKeys round.") + res_block = addroundkey(round_keys[0], tmp_block4) + + return res_block + + +#------------------------------------------------------------------- +# test_mixcolumns() +# +# Test the mixcolumns and inverse mixcolumns operations using +# some simple test values. +#------------------------------------------------------------------- +def test_mixcolumns(): + nist_aes128_key = (0x2b7e1516, 0x28aed2a6, 0xabf71588, 0x09cf4f3c) + + print("Test of mixcolumns and inverse mixcolumns:") + mixresult = mixcolumns(nist_aes128_key) + inv_mixresult = inv_mixcolumns(mixresult) + + print("Test of mixw ochi inv_mixw:") + testw = 0xdb135345 + expw = 0x8e4da1bc + mixresult = mixw(testw) + inv_mixresult = inv_mixw(mixresult) + print("Testword: 0x%08x" % testw) + print("expexted: 0x%08x" % expw) + print("mixword: 0x%08x" % mixresult) + print("invmixword: 0x%08x" % inv_mixresult) + + +#------------------------------------------------------------------- +# test_aes() +# +# Test the AES implementation with 128 and 256 bit keys. +#------------------------------------------------------------------- +def test_aes(): + nist_aes128_key = (0x2b7e1516, 0x28aed2a6, 0xabf71588, 0x09cf4f3c) + nist_aes256_key = (0x603deb10, 0x15ca71be, 0x2b73aef0, 0x857d7781, + 0x1f352c07, 0x3b6108d7, 0x2d9810a3, 0x0914dff4) + + nist_plaintext0 = (0x6bc1bee2, 0x2e409f96, 0xe93d7e11, 0x7393172a) + nist_plaintext1 = (0xae2d8a57, 0x1e03ac9c, 0x9eb76fac, 0x45af8e51) + nist_plaintext2 = (0x30c81c46, 0xa35ce411, 0xe5fbc119, 0x1a0a52ef) + nist_plaintext3 = (0xf69f2445, 0xdf4f9b17, 0xad2b417b, 0xe66c3710) + + nist_exp128_0 = (0x3ad77bb4, 0x0d7a3660, 0xa89ecaf3, 0x2466ef97) + nist_exp128_1 = (0xf5d3d585, 0x03b9699d, 0xe785895a, 0x96fdbaaf) + nist_exp128_2 = (0x43b1cd7f, 0x598ece23, 0x881b00e3, 0xed030688) + nist_exp128_3 = (0x7b0c785e, 0x27e8ad3f, 0x82232071, 0x04725dd4) + + nist_exp256_0 = (0xf3eed1bd, 0xb5d2a03c, 0x064b5a7e, 0x3db181f8) + nist_exp256_1 = (0x591ccb10, 0xd410ed26, 0xdc5ba74a, 0x31362870) + nist_exp256_2 = (0xb6ed21b9, 0x9ca6f4f9, 0xf153e7b1, 0xbeafed1d) + nist_exp256_3 = (0x23304b7a, 0x39f9f3ff, 0x067d8d8f, 0x9e24ecc7) + + + print("Doing block encryption.") + enc_result128_0 = aes_encipher_block(nist_aes128_key, nist_plaintext0) + enc_result128_1 = aes_encipher_block(nist_aes128_key, nist_plaintext1) + enc_result128_2 = aes_encipher_block(nist_aes128_key, nist_plaintext2) + enc_result128_3 = aes_encipher_block(nist_aes128_key, nist_plaintext3) + + enc_result256_0 = aes_encipher_block(nist_aes256_key, nist_plaintext0) + enc_result256_1 = aes_encipher_block(nist_aes256_key, nist_plaintext1) + enc_result256_2 = aes_encipher_block(nist_aes256_key, nist_plaintext2) + enc_result256_3 = aes_encipher_block(nist_aes256_key, nist_plaintext3) + + print("Doing block decryption.") + dec_result128_0 = aes_decipher_block(nist_aes128_key, nist_exp128_0) + dec_result128_1 = aes_decipher_block(nist_aes128_key, nist_exp128_1) + dec_result128_2 = aes_decipher_block(nist_aes128_key, nist_exp128_2) + dec_result128_3 = aes_decipher_block(nist_aes128_key, nist_exp128_3) + + dec_result256_0 = aes_decipher_block(nist_aes256_key, nist_exp256_0) + dec_result256_1 = aes_decipher_block(nist_aes256_key, nist_exp256_1) + dec_result256_2 = aes_decipher_block(nist_aes256_key, nist_exp256_2) + dec_result256_3 = aes_decipher_block(nist_aes256_key, nist_exp256_3) + + + if VERBOSE: + print(" AES Encipher tests") + print(" ==================") + + print("Test 0 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_plaintext0) + print("Expected block out:") + print_block(nist_exp128_0) + print("Got block out:") + print_block(enc_result128_0) + print("") + + print("Test 1 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_plaintext1) + print("Expected block out:") + print_block(nist_exp128_1) + print("Got block out:") + print_block(enc_result128_1) + print("") + + print("Test 2 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_plaintext2) + print("Expected block out:") + print_block(nist_exp128_2) + print("Got block out:") + print_block(enc_result128_2) + print("") + + print("Test 3 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_plaintext3) + print("Expected block out:") + print_block(nist_exp128_3) + print("Got block out:") + print_block(enc_result128_3) + print("") + + + print("Test 0 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_plaintext0) + print("Expected block out:") + print_block(nist_exp256_0) + print("Got block out:") + print_block(enc_result256_0) + print("") + + print("Test 1 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_plaintext1) + print("Expected block out:") + print_block(nist_exp256_1) + print("Got block out:") + print_block(enc_result256_1) + print("") + + print("Test 2 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_plaintext2) + print("Expected block out:") + print_block(nist_exp256_2) + print("Got block out:") + print_block(enc_result256_2) + print("") + + print("Test 3 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_plaintext3) + print("Expected block out:") + print_block(nist_exp256_3) + print("Got block out:") + print_block(enc_result256_3) + print("") + + print("") + print(" AES Decipher tests") + print(" ==================") + + print("Test 0 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_exp128_0) + print("Expected block out:") + print_block(nist_plaintext0) + print("Got block out:") + print_block(dec_result128_0) + print("") + + print("Test 1 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_exp128_1) + print("Expected block out:") + print_block(nist_plaintext1) + print("Got block out:") + print_block(dec_result128_1) + print("") + + print("Test 2 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_exp128_2) + print("Expected block out:") + print_block(nist_plaintext2) + print("Got block out:") + print_block(dec_result128_2) + print("") + + print("Test 3 for AES-128.") + print("Key:") + print_key(nist_aes128_key) + print("Block in:") + print_block(nist_exp128_3) + print("Expected block out:") + print_block(nist_plaintext3) + print("Got block out:") + print_block(dec_result128_3) + print("") + + print("Test 0 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_exp256_0) + print("Expected block out:") + print_block(nist_plaintext0) + print("Got block out:") + print_block(dec_result256_0) + print("") + + print("Test 1 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_exp256_1) + print("Expected block out:") + print_block(nist_plaintext1) + print("Got block out:") + print_block(dec_result256_1) + print("") + + print("Test 2 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_exp256_2) + print("Expected block out:") + print_block(nist_plaintext2) + print("Got block out:") + print_block(dec_result256_2) + print("") + + print("Test 3 for AES-256.") + print("Key:") + print_key(nist_aes256_key) + print("Block in:") + print_block(nist_exp256_3) + print("Expected block out:") + print_block(nist_plaintext3) + print("Got block out:") + print_block(dec_result256_3) + print("") + + +#------------------------------------------------------------------- +# main() +# +# If executed tests the ChaCha class using known test vectors. +#------------------------------------------------------------------- +def main(): + print("Testing the AES cipher model") + print("============================") + print + + # test_mixcolumns() + test_aes() + + +#------------------------------------------------------------------- +# __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 aes_key_gen.py +#======================================================================= -- cgit v1.2.3