undeath
7 years ago
6 changed files with 13 additions and 709 deletions
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#!/usr/bin/python |
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# |
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# aes.py: implements AES - Advanced Encryption Standard |
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# from the SlowAES project, http://code.google.com/p/slowaes/ |
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# |
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# Copyright (c) 2008 Josh Davis ( http://www.josh-davis.org ), |
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# Alex Martelli ( http://www.aleax.it ) |
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# |
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# Ported from C code written by Laurent Haan ( http://www.progressive-coding.com ) |
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# |
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# Licensed under the Apache License, Version 2.0 |
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# http://www.apache.org/licenses/ |
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# |
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from __future__ import (absolute_import, division, |
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print_function, unicode_literals) |
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from builtins import * |
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import math |
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import os |
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def append_PKCS7_padding(s): |
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"""return s padded to a multiple of 16-bytes by PKCS7 padding""" |
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numpads = 16 - (len(s) % 16) |
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return s + numpads * chr(numpads) |
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def strip_PKCS7_padding(s): |
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"""return s stripped of PKCS7 padding""" |
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if len(s) % 16 or not s: |
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raise ValueError("String of len %d can't be PCKS7-padded" % len(s)) |
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numpads = ord(s[-1]) |
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if numpads > 16: |
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raise ValueError("String ending with %r can't be PCKS7-padded" % s[-1]) |
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if not all(numpads == x for x in map(ord, s[-numpads:-1])): |
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raise ValueError("Invalid PKCS7 padding") |
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return s[:-numpads] |
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class AES(object): |
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# valid key sizes |
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keySize = dict(SIZE_128=16, SIZE_192=24, SIZE_256=32) |
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# Rijndael S-box |
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sbox = [0x63, 0x7c, 0x77, 0x7b, 0xf2, 0x6b, 0x6f, 0xc5, 0x30, 0x01, 0x67, |
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0x2b, 0xfe, 0xd7, 0xab, 0x76, 0xca, 0x82, 0xc9, 0x7d, 0xfa, 0x59, |
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0x47, 0xf0, 0xad, 0xd4, 0xa2, 0xaf, 0x9c, 0xa4, 0x72, 0xc0, 0xb7, |
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0xfd, 0x93, 0x26, 0x36, 0x3f, 0xf7, 0xcc, 0x34, 0xa5, 0xe5, 0xf1, |
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0x71, 0xd8, 0x31, 0x15, 0x04, 0xc7, 0x23, 0xc3, 0x18, 0x96, 0x05, |
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0x9a, 0x07, 0x12, 0x80, 0xe2, 0xeb, 0x27, 0xb2, 0x75, 0x09, 0x83, |
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0x2c, 0x1a, 0x1b, 0x6e, 0x5a, 0xa0, 0x52, 0x3b, 0xd6, 0xb3, 0x29, |
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0xe3, 0x2f, 0x84, 0x53, 0xd1, 0x00, 0xed, 0x20, 0xfc, 0xb1, 0x5b, |
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0x6a, 0xcb, 0xbe, 0x39, 0x4a, 0x4c, 0x58, 0xcf, 0xd0, 0xef, 0xaa, |
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0xfb, 0x43, 0x4d, 0x33, 0x85, 0x45, 0xf9, 0x02, 0x7f, 0x50, 0x3c, |
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0x9f, 0xa8, 0x51, 0xa3, 0x40, 0x8f, 0x92, 0x9d, 0x38, 0xf5, 0xbc, |
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0xb6, 0xda, 0x21, 0x10, 0xff, 0xf3, 0xd2, 0xcd, 0x0c, 0x13, 0xec, |
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0x5f, 0x97, 0x44, 0x17, 0xc4, 0xa7, 0x7e, 0x3d, 0x64, 0x5d, 0x19, |
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0x73, 0x60, 0x81, 0x4f, 0xdc, 0x22, 0x2a, 0x90, 0x88, 0x46, 0xee, |
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0xb8, 0x14, 0xde, 0x5e, 0x0b, 0xdb, 0xe0, 0x32, 0x3a, 0x0a, 0x49, |
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0x06, 0x24, 0x5c, 0xc2, 0xd3, 0xac, 0x62, 0x91, 0x95, 0xe4, 0x79, |
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0xe7, 0xc8, 0x37, 0x6d, 0x8d, 0xd5, 0x4e, 0xa9, 0x6c, 0x56, 0xf4, |
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0xea, 0x65, 0x7a, 0xae, 0x08, 0xba, 0x78, 0x25, 0x2e, 0x1c, 0xa6, |
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0xb4, 0xc6, 0xe8, 0xdd, 0x74, 0x1f, 0x4b, 0xbd, 0x8b, 0x8a, 0x70, |
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0x3e, 0xb5, 0x66, 0x48, 0x03, 0xf6, 0x0e, 0x61, 0x35, 0x57, 0xb9, |
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0x86, 0xc1, 0x1d, 0x9e, 0xe1, 0xf8, 0x98, 0x11, 0x69, 0xd9, 0x8e, |
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0x94, 0x9b, 0x1e, 0x87, 0xe9, 0xce, 0x55, 0x28, 0xdf, 0x8c, 0xa1, |
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0x89, 0x0d, 0xbf, 0xe6, 0x42, 0x68, 0x41, 0x99, 0x2d, 0x0f, 0xb0, |
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0x54, 0xbb, 0x16] |
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# Rijndael Inverted S-box |
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rsbox = [0x52, 0x09, 0x6a, 0xd5, 0x30, 0x36, 0xa5, 0x38, 0xbf, 0x40, 0xa3, |
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0x9e, 0x81, 0xf3, 0xd7, 0xfb, 0x7c, 0xe3, 0x39, 0x82, 0x9b, 0x2f, |
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0xff, 0x87, 0x34, 0x8e, 0x43, 0x44, 0xc4, 0xde, 0xe9, 0xcb, 0x54, |
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0x7b, 0x94, 0x32, 0xa6, 0xc2, 0x23, 0x3d, 0xee, 0x4c, 0x95, 0x0b, |
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0x42, 0xfa, 0xc3, 0x4e, 0x08, 0x2e, 0xa1, 0x66, 0x28, 0xd9, 0x24, |
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0xb2, 0x76, 0x5b, 0xa2, 0x49, 0x6d, 0x8b, 0xd1, 0x25, 0x72, 0xf8, |
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0xf6, 0x64, 0x86, 0x68, 0x98, 0x16, 0xd4, 0xa4, 0x5c, 0xcc, 0x5d, |
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0x65, 0xb6, 0x92, 0x6c, 0x70, 0x48, 0x50, 0xfd, 0xed, 0xb9, 0xda, |
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0x5e, 0x15, 0x46, 0x57, 0xa7, 0x8d, 0x9d, 0x84, 0x90, 0xd8, 0xab, |
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0x00, 0x8c, 0xbc, 0xd3, 0x0a, 0xf7, 0xe4, 0x58, 0x05, 0xb8, 0xb3, |
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0x45, 0x06, 0xd0, 0x2c, 0x1e, 0x8f, 0xca, 0x3f, 0x0f, 0x02, 0xc1, |
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0xaf, 0xbd, 0x03, 0x01, 0x13, 0x8a, 0x6b, 0x3a, 0x91, 0x11, 0x41, |
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0x4f, 0x67, 0xdc, 0xea, 0x97, 0xf2, 0xcf, 0xce, 0xf0, 0xb4, 0xe6, |
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0x73, 0x96, 0xac, 0x74, 0x22, 0xe7, 0xad, 0x35, 0x85, 0xe2, 0xf9, |
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0x37, 0xe8, 0x1c, 0x75, 0xdf, 0x6e, 0x47, 0xf1, 0x1a, 0x71, 0x1d, |
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0x29, 0xc5, 0x89, 0x6f, 0xb7, 0x62, 0x0e, 0xaa, 0x18, 0xbe, 0x1b, |
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0xfc, 0x56, 0x3e, 0x4b, 0xc6, 0xd2, 0x79, 0x20, 0x9a, 0xdb, 0xc0, |
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0xfe, 0x78, 0xcd, 0x5a, 0xf4, 0x1f, 0xdd, 0xa8, 0x33, 0x88, 0x07, |
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0xc7, 0x31, 0xb1, 0x12, 0x10, 0x59, 0x27, 0x80, 0xec, 0x5f, 0x60, |
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0x51, 0x7f, 0xa9, 0x19, 0xb5, 0x4a, 0x0d, 0x2d, 0xe5, 0x7a, 0x9f, |
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0x93, 0xc9, 0x9c, 0xef, 0xa0, 0xe0, 0x3b, 0x4d, 0xae, 0x2a, 0xf5, |
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0xb0, 0xc8, 0xeb, 0xbb, 0x3c, 0x83, 0x53, 0x99, 0x61, 0x17, 0x2b, |
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0x04, 0x7e, 0xba, 0x77, 0xd6, 0x26, 0xe1, 0x69, 0x14, 0x63, 0x55, |
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0x21, 0x0c, 0x7d] |
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def getSBoxValue(self, num): |
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"""Retrieves a given S-Box Value""" |
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return self.sbox[num] |
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def getSBoxInvert(self, num): |
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"""Retrieves a given Inverted S-Box Value""" |
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return self.rsbox[num] |
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@staticmethod |
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def rotate(word): |
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""" Rijndael's key schedule rotate operation. |
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Rotate a word eight bits to the left: eg, rotate(1d2c3a4f) == 2c3a4f1d |
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Word is an char list of size 4 (32 bits overall). |
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""" |
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return word[1:] + word[:1] |
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# Rijndael Rcon |
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Rcon = [0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, |
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0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, |
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0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, |
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0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, |
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0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, |
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0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, |
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0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, |
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0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, |
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0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, |
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0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, |
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0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, |
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0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, |
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0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, |
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0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, |
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0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, |
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0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, |
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0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, |
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0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, |
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0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, |
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0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, |
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0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, |
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0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, |
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0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, |
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0xe8, 0xcb] |
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def getRconValue(self, num): |
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"""Retrieves a given Rcon Value""" |
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return self.Rcon[num] |
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def core(self, word, iteration): |
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"""Key schedule core.""" |
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# rotate the 32-bit word 8 bits to the left |
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word = self.rotate(word) |
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# apply S-Box substitution on all 4 parts of the 32-bit word |
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for i in range(4): |
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word[i] = self.getSBoxValue(word[i]) |
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# XOR the output of the rcon operation with i to the first part |
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# (leftmost) only |
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word[0] = word[0] ^ self.getRconValue(iteration) |
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return word |
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def expandKey(self, key, size, expandedKeySize): |
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"""Rijndael's key expansion. |
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Expands an 128,192,256 key into an 176,208,240 bytes key |
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expandedKey is a char list of large enough size, |
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key is the non-expanded key. |
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""" |
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# current expanded keySize, in bytes |
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currentSize = 0 |
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rconIteration = 1 |
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expandedKey = [0] * expandedKeySize |
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# set the 16, 24, 32 bytes of the expanded key to the input key |
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for j in range(size): |
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expandedKey[j] = key[j] |
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currentSize += size |
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while currentSize < expandedKeySize: |
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# assign the previous 4 bytes to the temporary value t |
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t = expandedKey[currentSize - 4:currentSize] |
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# every 16,24,32 bytes we apply the core schedule to t |
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# and increment rconIteration afterwards |
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if currentSize % size == 0: |
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t = self.core(t, rconIteration) |
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rconIteration += 1 |
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# For 256-bit keys, we add an extra sbox to the calculation |
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if size == self.keySize["SIZE_256"] and ( |
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(currentSize % size) == 16): |
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for l in range(4): |
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t[l] = self.getSBoxValue(t[l]) |
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# We XOR t with the four-byte block 16,24,32 bytes before the new |
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# expanded key. This becomes the next four bytes in the expanded |
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# key. |
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for m in range(4): |
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expandedKey[currentSize] = expandedKey[currentSize - size] ^ \ |
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t[m] |
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currentSize += 1 |
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return expandedKey |
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@staticmethod |
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def addRoundKey(state, roundKey): |
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"""Adds (XORs) the round key to the state.""" |
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for i in range(16): |
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state[i] ^= roundKey[i] |
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return state |
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@staticmethod |
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def createRoundKey(expandedKey, roundKeyPointer): |
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"""Create a round key. |
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Creates a round key from the given expanded key and the |
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position within the expanded key. |
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""" |
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roundKey = [0] * 16 |
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for i in range(4): |
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for j in range(4): |
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roundKey[j * 4 + i] = expandedKey[roundKeyPointer + i * 4 + j] |
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return roundKey |
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@staticmethod |
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def galois_multiplication(a, b): |
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"""Galois multiplication of 8 bit characters a and b.""" |
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p = 0 |
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for counter in range(8): |
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if b & 1: p ^= a |
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hi_bit_set = a & 0x80 |
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a <<= 1 |
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# keep a 8 bit |
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a &= 0xFF |
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if hi_bit_set: |
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a ^= 0x1b |
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b >>= 1 |
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return p |
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# |
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# substitute all the values from the state with the value in the SBox |
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# using the state value as index for the SBox |
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# |
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def subBytes(self, state, isInv): |
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if isInv: |
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getter = self.getSBoxInvert |
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else: |
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getter = self.getSBoxValue |
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for i in range(16): |
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state[i] = getter(state[i]) |
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return state |
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# iterate over the 4 rows and call shiftRow() with that row |
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def shiftRows(self, state, isInv): |
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for i in range(4): |
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state = self.shiftRow(state, i * 4, i, isInv) |
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return state |
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# each iteration shifts the row to the left by 1 |
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@staticmethod |
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def shiftRow(state, statePointer, nbr, isInv): |
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for i in range(nbr): |
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if isInv: |
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state[statePointer:statePointer + 4] = \ |
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state[statePointer + 3:statePointer + 4] + \ |
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state[statePointer:statePointer + 3] |
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else: |
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state[statePointer:statePointer + 4] = \ |
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state[statePointer + 1:statePointer + 4] + \ |
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state[statePointer:statePointer + 1] |
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return state |
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# galois multiplication of the 4x4 matrix |
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def mixColumns(self, state, isInv): |
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# iterate over the 4 columns |
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for i in range(4): |
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# construct one column by slicing over the 4 rows |
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column = state[i:i + 16:4] |
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# apply the mixColumn on one column |
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column = self.mixColumn(column, isInv) |
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# put the values back into the state |
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state[i:i + 16:4] = column |
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return state |
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# galois multiplication of 1 column of the 4x4 matrix |
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def mixColumn(self, column, isInv): |
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if isInv: |
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mult = [14, 9, 13, 11] |
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else: |
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mult = [2, 1, 1, 3] |
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cpy = list(column) |
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g = self.galois_multiplication |
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column[0] = g(cpy[0], mult[0]) ^ g(cpy[3], mult[1]) ^ \ |
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g(cpy[2], mult[2]) ^ g(cpy[1], mult[3]) |
|
||||||
column[1] = g(cpy[1], mult[0]) ^ g(cpy[0], mult[1]) ^ \ |
|
||||||
g(cpy[3], mult[2]) ^ g(cpy[2], mult[3]) |
|
||||||
column[2] = g(cpy[2], mult[0]) ^ g(cpy[1], mult[1]) ^ \ |
|
||||||
g(cpy[0], mult[2]) ^ g(cpy[3], mult[3]) |
|
||||||
column[3] = g(cpy[3], mult[0]) ^ g(cpy[2], mult[1]) ^ \ |
|
||||||
g(cpy[1], mult[2]) ^ g(cpy[0], mult[3]) |
|
||||||
return column |
|
||||||
|
|
||||||
# applies the 4 operations of the forward round in sequence |
|
||||||
def aes_round(self, state, roundKey): |
|
||||||
state = self.subBytes(state, False) |
|
||||||
state = self.shiftRows(state, False) |
|
||||||
state = self.mixColumns(state, False) |
|
||||||
state = self.addRoundKey(state, roundKey) |
|
||||||
return state |
|
||||||
|
|
||||||
# applies the 4 operations of the inverse round in sequence |
|
||||||
def aes_invRound(self, state, roundKey): |
|
||||||
state = self.shiftRows(state, True) |
|
||||||
state = self.subBytes(state, True) |
|
||||||
state = self.addRoundKey(state, roundKey) |
|
||||||
state = self.mixColumns(state, True) |
|
||||||
return state |
|
||||||
|
|
||||||
# Perform the initial operations, the standard round, and the final |
|
||||||
# operations of the forward aes, creating a round key for each round |
|
||||||
def aes_main(self, state, expandedKey, nbrRounds): |
|
||||||
state = self.addRoundKey(state, self.createRoundKey(expandedKey, 0)) |
|
||||||
i = 1 |
|
||||||
while i < nbrRounds: |
|
||||||
state = self.aes_round(state, |
|
||||||
self.createRoundKey(expandedKey, 16 * i)) |
|
||||||
i += 1 |
|
||||||
state = self.subBytes(state, False) |
|
||||||
state = self.shiftRows(state, False) |
|
||||||
state = self.addRoundKey( |
|
||||||
state, self.createRoundKey(expandedKey, 16 * nbrRounds)) |
|
||||||
return state |
|
||||||
|
|
||||||
# Perform the initial operations, the standard round, and the final |
|
||||||
# operations of the inverse aes, creating a round key for each round |
|
||||||
def aes_invMain(self, state, expandedKey, nbrRounds): |
|
||||||
state = self.addRoundKey( |
|
||||||
state, self.createRoundKey(expandedKey, 16 * nbrRounds)) |
|
||||||
i = nbrRounds - 1 |
|
||||||
while i > 0: |
|
||||||
state = self.aes_invRound(state, |
|
||||||
self.createRoundKey(expandedKey, 16 * i)) |
|
||||||
i -= 1 |
|
||||||
state = self.shiftRows(state, True) |
|
||||||
state = self.subBytes(state, True) |
|
||||||
state = self.addRoundKey(state, self.createRoundKey(expandedKey, 0)) |
|
||||||
return state |
|
||||||
|
|
||||||
# encrypts a 128 bit input block against the given key of size specified |
|
||||||
def encrypt(self, iput, key, size): |
|
||||||
output = [0] * 16 |
|
||||||
# the number of rounds |
|
||||||
nbrRounds = 0 |
|
||||||
# the 128 bit block to encode |
|
||||||
block = [0] * 16 |
|
||||||
# set the number of rounds |
|
||||||
if size == self.keySize["SIZE_128"]: |
|
||||||
nbrRounds = 10 |
|
||||||
elif size == self.keySize["SIZE_192"]: |
|
||||||
nbrRounds = 12 |
|
||||||
elif size == self.keySize["SIZE_256"]: |
|
||||||
nbrRounds = 14 |
|
||||||
else: |
|
||||||
return None |
|
||||||
|
|
||||||
# the expanded keySize |
|
||||||
expandedKeySize = 16 * (nbrRounds + 1) |
|
||||||
|
|
||||||
# Set the block values, for the block: |
|
||||||
# a0,0 a0,1 a0,2 a0,3 |
|
||||||
# a1,0 a1,1 a1,2 a1,3 |
|
||||||
# a2,0 a2,1 a2,2 a2,3 |
|
||||||
# a3,0 a3,1 a3,2 a3,3 |
|
||||||
# the mapping order is a0,0 a1,0 a2,0 a3,0 a0,1 a1,1 ... a2,3 a3,3 |
|
||||||
# |
|
||||||
# iterate over the columns |
|
||||||
for i in range(4): |
|
||||||
# iterate over the rows |
|
||||||
for j in range(4): |
|
||||||
block[(i + (j * 4))] = iput[(i * 4) + j] |
|
||||||
|
|
||||||
# expand the key into an 176, 208, 240 bytes key |
|
||||||
# the expanded key |
|
||||||
expandedKey = self.expandKey(key, size, expandedKeySize) |
|
||||||
|
|
||||||
# encrypt the block using the expandedKey |
|
||||||
block = self.aes_main(block, expandedKey, nbrRounds) |
|
||||||
|
|
||||||
# unmap the block again into the output |
|
||||||
for k in range(4): |
|
||||||
# iterate over the rows |
|
||||||
for l in range(4): |
|
||||||
output[(k * 4) + l] = block[(k + (l * 4))] |
|
||||||
return output |
|
||||||
|
|
||||||
# decrypts a 128 bit input block against the given key of size specified |
|
||||||
def decrypt(self, iput, key, size): |
|
||||||
output = [0] * 16 |
|
||||||
# the number of rounds |
|
||||||
nbrRounds = 0 |
|
||||||
# the 128 bit block to decode |
|
||||||
block = [0] * 16 |
|
||||||
# set the number of rounds |
|
||||||
if size == self.keySize["SIZE_128"]: |
|
||||||
nbrRounds = 10 |
|
||||||
elif size == self.keySize["SIZE_192"]: |
|
||||||
nbrRounds = 12 |
|
||||||
elif size == self.keySize["SIZE_256"]: |
|
||||||
nbrRounds = 14 |
|
||||||
else: |
|
||||||
return None |
|
||||||
|
|
||||||
# the expanded keySize |
|
||||||
expandedKeySize = 16 * (nbrRounds + 1) |
|
||||||
|
|
||||||
# Set the block values, for the block: |
|
||||||
# a0,0 a0,1 a0,2 a0,3 |
|
||||||
# a1,0 a1,1 a1,2 a1,3 |
|
||||||
# a2,0 a2,1 a2,2 a2,3 |
|
||||||
# a3,0 a3,1 a3,2 a3,3 |
|
||||||
# the mapping order is a0,0 a1,0 a2,0 a3,0 a0,1 a1,1 ... a2,3 a3,3 |
|
||||||
|
|
||||||
# iterate over the columns |
|
||||||
for i in range(4): |
|
||||||
# iterate over the rows |
|
||||||
for j in range(4): |
|
||||||
block[(i + (j * 4))] = iput[(i * 4) + j] |
|
||||||
# expand the key into an 176, 208, 240 bytes key |
|
||||||
expandedKey = self.expandKey(key, size, expandedKeySize) |
|
||||||
# decrypt the block using the expandedKey |
|
||||||
block = self.aes_invMain(block, expandedKey, nbrRounds) |
|
||||||
# unmap the block again into the output |
|
||||||
for k in range(4): |
|
||||||
# iterate over the rows |
|
||||||
for l in range(4): |
|
||||||
output[(k * 4) + l] = block[(k + (l * 4))] |
|
||||||
return output |
|
||||||
|
|
||||||
|
|
||||||
class AESModeOfOperation(object): |
|
||||||
aes = AES() |
|
||||||
|
|
||||||
# structure of supported modes of operation |
|
||||||
modeOfOperation = dict(OFB=0, CFB=1, CBC=2) |
|
||||||
|
|
||||||
# converts a 16 character string into a number array |
|
||||||
def convertString(self, string, start, end, mode): |
|
||||||
if end - start > 16: end = start + 16 |
|
||||||
if mode == self.modeOfOperation["CBC"]: |
|
||||||
ar = [0] * 16 |
|
||||||
else: |
|
||||||
ar = [] |
|
||||||
|
|
||||||
i = start |
|
||||||
j = 0 |
|
||||||
while len(ar) < end - start: |
|
||||||
ar.append(0) |
|
||||||
while i < end: |
|
||||||
ar[j] = ord(string[i]) |
|
||||||
j += 1 |
|
||||||
i += 1 |
|
||||||
return ar |
|
||||||
|
|
||||||
# Mode of Operation Encryption |
|
||||||
# stringIn - Input String |
|
||||||
# mode - mode of type modeOfOperation |
|
||||||
# hexKey - a hex key of the bit length size |
|
||||||
# size - the bit length of the key |
|
||||||
# hexIV - the 128 bit hex Initilization Vector |
|
||||||
def encrypt(self, stringIn, mode, key, size, IV): |
|
||||||
if len(key) % size: |
|
||||||
return None |
|
||||||
if len(IV) % 16: |
|
||||||
return None |
|
||||||
# the AES input/output |
|
||||||
plaintext = [] |
|
||||||
iput = [0] * 16 |
|
||||||
output = [] |
|
||||||
ciphertext = [0] * 16 |
|
||||||
# the output cipher string |
|
||||||
cipherOut = [] |
|
||||||
# char firstRound |
|
||||||
firstRound = True |
|
||||||
if stringIn is not None: |
|
||||||
for j in range(int(math.ceil(float(len(stringIn)) / 16))): |
|
||||||
start = j * 16 |
|
||||||
end = j * 16 + 16 |
|
||||||
if end > len(stringIn): |
|
||||||
end = len(stringIn) |
|
||||||
plaintext = self.convertString(stringIn, start, end, mode) |
|
||||||
# print 'PT@%s:%s' % (j, plaintext) |
|
||||||
if mode == self.modeOfOperation["CFB"]: |
|
||||||
if firstRound: |
|
||||||
output = self.aes.encrypt(IV, key, size) |
|
||||||
firstRound = False |
|
||||||
else: |
|
||||||
output = self.aes.encrypt(iput, key, size) |
|
||||||
for i in range(16): |
|
||||||
if len(plaintext) - 1 < i: |
|
||||||
ciphertext[i] = 0 ^ output[i] |
|
||||||
elif len(output) - 1 < i: |
|
||||||
ciphertext[i] = plaintext[i] ^ 0 |
|
||||||
elif len(plaintext) - 1 < i and len(output) < i: |
|
||||||
ciphertext[i] = 0 ^ 0 |
|
||||||
else: |
|
||||||
ciphertext[i] = plaintext[i] ^ output[i] |
|
||||||
for k in range(end - start): |
|
||||||
cipherOut.append(ciphertext[k]) |
|
||||||
iput = ciphertext |
|
||||||
elif mode == self.modeOfOperation["OFB"]: |
|
||||||
if firstRound: |
|
||||||
output = self.aes.encrypt(IV, key, size) |
|
||||||
firstRound = False |
|
||||||
else: |
|
||||||
output = self.aes.encrypt(iput, key, size) |
|
||||||
for i in range(16): |
|
||||||
if len(plaintext) - 1 < i: |
|
||||||
ciphertext[i] = 0 ^ output[i] |
|
||||||
elif len(output) - 1 < i: |
|
||||||
ciphertext[i] = plaintext[i] ^ 0 |
|
||||||
elif len(plaintext) - 1 < i and len(output) < i: |
|
||||||
ciphertext[i] = 0 ^ 0 |
|
||||||
else: |
|
||||||
ciphertext[i] = plaintext[i] ^ output[i] |
|
||||||
for k in range(end - start): |
|
||||||
cipherOut.append(ciphertext[k]) |
|
||||||
iput = output |
|
||||||
elif mode == self.modeOfOperation["CBC"]: |
|
||||||
for i in range(16): |
|
||||||
if firstRound: |
|
||||||
iput[i] = plaintext[i] ^ IV[i] |
|
||||||
else: |
|
||||||
iput[i] = plaintext[i] ^ ciphertext[i] |
|
||||||
# print 'IP@%s:%s' % (j, iput) |
|
||||||
firstRound = False |
|
||||||
ciphertext = self.aes.encrypt(iput, key, size) |
|
||||||
# always 16 bytes because of the padding for CBC |
|
||||||
for k in range(16): |
|
||||||
cipherOut.append(ciphertext[k]) |
|
||||||
return mode, len(stringIn), cipherOut |
|
||||||
|
|
||||||
# Mode of Operation Decryption |
|
||||||
# cipherIn - Encrypted String |
|
||||||
# originalsize - The unencrypted string length - required for CBC |
|
||||||
# mode - mode of type modeOfOperation |
|
||||||
# key - a number array of the bit length size |
|
||||||
# size - the bit length of the key |
|
||||||
# IV - the 128 bit number array Initilization Vector |
|
||||||
def decrypt(self, cipherIn, originalsize, mode, key, size, IV): |
|
||||||
# cipherIn = unescCtrlChars(cipherIn) |
|
||||||
if len(key) % size: |
|
||||||
return None |
|
||||||
if len(IV) % 16: |
|
||||||
return None |
|
||||||
# the AES input/output |
|
||||||
ciphertext = [] |
|
||||||
iput = [] |
|
||||||
output = [] |
|
||||||
plaintext = [0] * 16 |
|
||||||
# the output plain text string |
|
||||||
stringOut = '' |
|
||||||
# char firstRound |
|
||||||
firstRound = True |
|
||||||
if cipherIn is not None: |
|
||||||
for j in range(int(math.ceil(float(len(cipherIn)) / 16))): |
|
||||||
start = j * 16 |
|
||||||
end = j * 16 + 16 |
|
||||||
if j * 16 + 16 > len(cipherIn): |
|
||||||
end = len(cipherIn) |
|
||||||
ciphertext = cipherIn[start:end] |
|
||||||
if mode == self.modeOfOperation["CFB"]: |
|
||||||
if firstRound: |
|
||||||
output = self.aes.encrypt(IV, key, size) |
|
||||||
firstRound = False |
|
||||||
else: |
|
||||||
output = self.aes.encrypt(iput, key, size) |
|
||||||
for i in range(16): |
|
||||||
if len(output) - 1 < i: |
|
||||||
plaintext[i] = 0 ^ ciphertext[i] |
|
||||||
elif len(ciphertext) - 1 < i: |
|
||||||
plaintext[i] = output[i] ^ 0 |
|
||||||
elif len(output) - 1 < i and len(ciphertext) < i: |
|
||||||
plaintext[i] = 0 ^ 0 |
|
||||||
else: |
|
||||||
plaintext[i] = output[i] ^ ciphertext[i] |
|
||||||
for k in range(end - start): |
|
||||||
stringOut += chr(plaintext[k]) |
|
||||||
iput = ciphertext |
|
||||||
elif mode == self.modeOfOperation["OFB"]: |
|
||||||
if firstRound: |
|
||||||
output = self.aes.encrypt(IV, key, size) |
|
||||||
firstRound = False |
|
||||||
else: |
|
||||||
output = self.aes.encrypt(iput, key, size) |
|
||||||
for i in range(16): |
|
||||||
if len(output) - 1 < i: |
|
||||||
plaintext[i] = 0 ^ ciphertext[i] |
|
||||||
elif len(ciphertext) - 1 < i: |
|
||||||
plaintext[i] = output[i] ^ 0 |
|
||||||
elif len(output) - 1 < i and len(ciphertext) < i: |
|
||||||
plaintext[i] = 0 ^ 0 |
|
||||||
else: |
|
||||||
plaintext[i] = output[i] ^ ciphertext[i] |
|
||||||
for k in range(end - start): |
|
||||||
stringOut += chr(plaintext[k]) |
|
||||||
iput = output |
|
||||||
elif mode == self.modeOfOperation["CBC"]: |
|
||||||
output = self.aes.decrypt(ciphertext, key, size) |
|
||||||
for i in range(16): |
|
||||||
if firstRound: |
|
||||||
plaintext[i] = IV[i] ^ output[i] |
|
||||||
else: |
|
||||||
plaintext[i] = iput[i] ^ output[i] |
|
||||||
firstRound = False |
|
||||||
if originalsize is not None and originalsize < end: |
|
||||||
for k in range(originalsize - start): |
|
||||||
stringOut += chr(plaintext[k]) |
|
||||||
else: |
|
||||||
for k in range(end - start): |
|
||||||
stringOut += chr(plaintext[k]) |
|
||||||
iput = ciphertext |
|
||||||
return stringOut |
|
||||||
|
|
||||||
|
|
||||||
def encryptData(key, data, mode=AESModeOfOperation.modeOfOperation["CBC"]): |
|
||||||
"""encrypt `data` using `key` |
|
||||||
|
|
||||||
`key` should be a string of bytes. |
|
||||||
|
|
||||||
returned cipher is a string of bytes prepended with the initialization |
|
||||||
vector. |
|
||||||
|
|
||||||
""" |
|
||||||
key = map(ord, key) |
|
||||||
if mode == AESModeOfOperation.modeOfOperation["CBC"]: |
|
||||||
data = append_PKCS7_padding(data) |
|
||||||
keysize = len(key) |
|
||||||
assert keysize in AES.keySize.values(), 'invalid key size: %s' % keysize |
|
||||||
# create a new iv using random data |
|
||||||
iv = [ord(i) for i in os.urandom(16)] |
|
||||||
moo = AESModeOfOperation() |
|
||||||
(mode, length, ciph) = moo.encrypt(data, mode, key, keysize, iv) |
|
||||||
# With padding, the original length does not need to be known. It's a bad |
|
||||||
# idea to store the original message length. |
|
||||||
# prepend the iv. |
|
||||||
return ''.join(map(chr, iv)) + ''.join(map(chr, ciph)) |
|
||||||
|
|
||||||
|
|
||||||
def decryptData(key, data, mode=AESModeOfOperation.modeOfOperation["CBC"]): |
|
||||||
"""decrypt `data` using `key` |
|
||||||
|
|
||||||
`key` should be a string of bytes. |
|
||||||
|
|
||||||
`data` should have the initialization vector prepended as a string of |
|
||||||
ordinal values. |
|
||||||
|
|
||||||
""" |
|
||||||
|
|
||||||
key = map(ord, key) |
|
||||||
keysize = len(key) |
|
||||||
assert keysize in AES.keySize.values(), 'invalid key size: %s' % keysize |
|
||||||
# iv is first 16 bytes |
|
||||||
iv = map(ord, data[:16]) |
|
||||||
data = map(ord, data[16:]) |
|
||||||
moo = AESModeOfOperation() |
|
||||||
decr = moo.decrypt(data, None, mode, key, keysize, iv) |
|
||||||
if mode == AESModeOfOperation.modeOfOperation["CBC"]: |
|
||||||
decr = strip_PKCS7_padding(decr) |
|
||||||
return decr |
|
||||||
|
|
||||||
@ -1,36 +0,0 @@ |
|||||||
from __future__ import (absolute_import, division, |
|
||||||
print_function, unicode_literals) |
|
||||||
from builtins import * # noqa: F401 |
|
||||||
import jmclient.slowaes as sa |
|
||||||
"""test general AES operation; probably not needed. |
|
||||||
Not included in coverage, but should be included in suite.""" |
|
||||||
import os |
|
||||||
import sys |
|
||||||
import pytest |
|
||||||
|
|
||||||
def test_pkcs7_bad_padding(): |
|
||||||
#used in seed decryption; check that it throws |
|
||||||
#if wrongly padded (this caused a REAL bug before!) |
|
||||||
bad_padded = [b'\x07'*14, b'\x07'*31, b'\x07'*31+b'\x11', b'\x07'*31+b'\x00', |
|
||||||
b'\x07'*14+b'\x01\x02'] |
|
||||||
for b in bad_padded: |
|
||||||
with pytest.raises(Exception) as e_info: |
|
||||||
fake_unpadded = sa.strip_PKCS7_padding(b) |
|
||||||
|
|
||||||
def test_aes(): |
|
||||||
cleartext = "This is a test!" |
|
||||||
iv = [103, 35, 148, 239, 76, 213, 47, 118, 255, 222, 123, 176, 106, 134, 98, |
|
||||||
92] |
|
||||||
for ks in [16,24,32]: |
|
||||||
for mode in ["CFB", "CBC", "OFB"]: |
|
||||||
if sys.version_info >= (3,0): |
|
||||||
cypherkey = list(map(int, os.urandom(ks))) |
|
||||||
else: |
|
||||||
cypherkey = list(map(ord, os.urandom(ks))) |
|
||||||
moo = sa.AESModeOfOperation() |
|
||||||
mode, orig_len, ciph = moo.encrypt(cleartext, moo.modeOfOperation[mode], |
|
||||||
cypherkey, ks, |
|
||||||
iv) |
|
||||||
decr = moo.decrypt(ciph, orig_len, mode, cypherkey, |
|
||||||
ks, iv) |
|
||||||
assert decr==cleartext |
|
||||||
Loading…
Reference in new issue