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Delete aes.py
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Matteo ℱan
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aes.py
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aes.py
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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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import os
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import sys
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import math
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class AES(object):
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'''AES funtions for a single block
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'''
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# Very annoying code: all is for an object, but no state is kept!
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# Should just be plain functions in a AES modlule.
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v6 = False
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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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def rotate(self, 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 ((currentSize % size) == 16):
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for l in range(4): 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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def addRoundKey(self, 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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def createRoundKey(self, 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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def galois_multiplication(self, 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: getter = self.getSBoxInvert
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else: getter = self.getSBoxValue
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for i in range(16): 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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def shiftRow(self, 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: mult = [14, 9, 13, 11]
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else: 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])
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column[1] = g(cpy[1], mult[0]) ^ g(cpy[0], mult[1]) ^ \
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g(cpy[3], mult[2]) ^ g(cpy[2], mult[3])
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column[2] = g(cpy[2], mult[0]) ^ g(cpy[1], mult[1]) ^ \
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g(cpy[0], mult[2]) ^ g(cpy[3], mult[3])
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column[3] = g(cpy[3], mult[0]) ^ g(cpy[2], mult[1]) ^ \
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g(cpy[1], mult[2]) ^ g(cpy[0], mult[3])
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return column
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# applies the 4 operations of the forward round in sequence
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def aes_round(self, state, roundKey, round):
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state = self.subBytes(state, False)
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state = self.shiftRows(state, False)
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state = self.mixColumns(state, False)
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if self.v6:
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if round == 4:
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state[0]^=0x73
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if round == 6:
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state[0]^=0x09
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if round == 8:
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state[0]^=0xE4
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state = self.addRoundKey(state, roundKey)
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return state
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# applies the 4 operations of the inverse round in sequence
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def aes_invRound(self, state, roundKey, round):
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state = self.shiftRows(state, True)
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state = self.subBytes(state, True)
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state = self.addRoundKey(state, roundKey)
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if self.v6:
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if round == 4:
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state[0]^=0x73
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if round == 6:
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state[0]^=0x09
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if round == 8:
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state[0]^=0xE4
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state = self.mixColumns(state, True)
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return state
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# Perform the initial operations, the standard round, and the final
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# operations of the forward aes, creating a round key for each round
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def aes_main(self, state, expandedKey, nbrRounds):
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state = self.addRoundKey(state, self.createRoundKey(expandedKey, 0))
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i = 1
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while i < nbrRounds:
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state = self.aes_round(state,
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self.createRoundKey(expandedKey, 16*i), i)
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i += 1
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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)
|
||||
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
|
||||
# The KMS v4 parameters
|
||||
elif size == 20: nbrRounds = 11
|
||||
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):
|
||||
'''Handles AES with plaintext consistingof multiple blocks.
|
||||
Choice of block encoding modes: OFT, CFB, CBC
|
||||
'''
|
||||
# Very annoying code: all is for an object, but no state is kept!
|
||||
# Should just be plain functions in an AES_BlockMode module.
|
||||
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 != 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 character list
|
||||
chrOut = []
|
||||
# char firstRound
|
||||
firstRound = True
|
||||
if cipherIn != 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):
|
||||
chrOut.append(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):
|
||||
chrOut.append(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):
|
||||
chrOut.append(chr(plaintext[k]))
|
||||
else:
|
||||
for k in range(end-start):
|
||||
chrOut.append(chr(plaintext[k]))
|
||||
iput = ciphertext
|
||||
return "".join(chrOut)
|
||||
|
||||
|
||||
def append_PKCS7_padding(s):
|
||||
"""return s padded to a multiple of 16-bytes by PKCS7 padding"""
|
||||
numpads = 16 - (len(s)%16)
|
||||
return s + numpads*chr(numpads)
|
||||
|
||||
def strip_PKCS7_padding(s):
|
||||
"""return s stripped of PKCS7 padding"""
|
||||
if len(s)%16 or not s:
|
||||
raise ValueError("String of len %d can't be PCKS7-padded" % len(s))
|
||||
numpads = ord(s[-1])
|
||||
if numpads > 16:
|
||||
return s
|
||||
# raise ValueError("String ending with %r can't be PCKS7-padded" % s[-1])
|
||||
return s[:-numpads]
|
||||
|
||||
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
|
||||
|
||||
def generateRandomKey(keysize):
|
||||
"""Generates a key from random data of length `keysize`.
|
||||
The returned key is a string of bytes.
|
||||
"""
|
||||
if keysize not in (16, 24, 32):
|
||||
emsg = 'Invalid keysize, %s. Should be one of (16, 24, 32).'
|
||||
raise ValueError, emsg % keysize
|
||||
return os.urandom(keysize)
|
||||
|
||||
def testStr(cleartext, keysize=16, modeName = "CBC"):
|
||||
'''Test with random key, choice of mode.'''
|
||||
print 'Random key test', 'Mode:', modeName
|
||||
print 'cleartext:', cleartext
|
||||
key = generateRandomKey(keysize)
|
||||
print 'Key:', [ord(x) for x in key]
|
||||
mode = AESModeOfOperation.modeOfOperation[modeName]
|
||||
cipher = encryptData(key, cleartext, mode)
|
||||
print 'Cipher:', [ord(x) for x in cipher]
|
||||
decr = decryptData(key, cipher, mode)
|
||||
print 'Decrypted:', decr
|
||||
|
||||
|
||||
if __name__ == "__main__":
|
||||
moo = AESModeOfOperation()
|
||||
cleartext = "This is a test with several blocks!"
|
||||
cypherkey = [143,194,34,208,145,203,230,143,177,246,97,206,145,92,255,84]
|
||||
iv = [103,35,148,239,76,213,47,118,255,222,123,176,106,134,98,92]
|
||||
mode, orig_len, ciph = moo.encrypt(cleartext, moo.modeOfOperation["CBC"],
|
||||
cypherkey, moo.aes.keySize["SIZE_128"], iv)
|
||||
print 'm=%s, ol=%s (%s), ciph=%s' % (mode, orig_len, len(cleartext), ciph)
|
||||
decr = moo.decrypt(ciph, orig_len, mode, cypherkey,
|
||||
moo.aes.keySize["SIZE_128"], iv)
|
||||
print decr
|
||||
testStr(cleartext, 16, "CBC")
|
||||
Loading…
Reference in New Issue
Block a user