#!/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 #=======================================================================