--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/Utilities/crypto/py3AES.py Sun Jun 19 15:19:46 2011 +0200
@@ -0,0 +1,835 @@
+#!/usr/bin/python3
+#
+# aes.py: implements AES - Advanced Encryption Standard
+# from the SlowAES project, http://code.google.com/p/slowaes/
+#
+# Copyright (c) 2008 Josh Davis ( http://www.josh-davis.org ),
+# Alex Martelli ( http://www.aleax.it )
+#
+# Ported from C code written by Laurent Haan ( http://www.progressive-coding.com )
+#
+# Licensed under the Apache License, Version 2.0
+# http://www.apache.org/licenses/
+#
+
+#
+# Ported to Python3
+#
+# Copyright (c) 2011 Detlev Offenbach <detlev@die-offenbachs.de>
+#
+
+"""
+Module implementing classes for encryption according
+Advanced Encryption Standard.
+"""
+
+import os
+import math
+
+
+def append_PKCS7_padding(b):
+ """
+ Function to pad the given data to a multiple of 16-bytes by PKCS7 padding.
+
+ @param b data to be padded (bytes)
+ @return padded data (bytes)
+ """
+ numpads = 16 - (len(b) % 16)
+ return b + numpads * bytes(chr(numpads), encoding="ascii")
+
+
+def strip_PKCS7_padding(b):
+ """
+ Function to strip off PKCS7 padding.
+
+ @param b data to be stripped (bytes)
+ @return stripped data (bytes)
+ """
+ if len(b) % 16 or not b:
+ raise ValueError("Data of len {0} can't be PCKS7-padded".format(len(b)))
+ numpads = b[-1]
+ if numpads > 16:
+ raise ValueError("Data ending with {0} can't be PCKS7-padded".format(b[-1]))
+ return b[:-numpads]
+
+
+class AES(object):
+ """
+ Class implementing the Advanced Encryption Standard algorithm.
+ """
+ # valid key sizes
+ KeySize = {
+ "SIZE_128": 16,
+ "SIZE_192": 24,
+ "SIZE_256": 32,
+ }
+
+ # Rijndael S-box
+ 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]
+
+ # Rijndael Inverted S-box
+ rsbox = [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]
+
+ # Rijndael Rcon
+ Rcon = [0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36,
+ 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97,
+ 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72,
+ 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66,
+ 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04,
+ 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d,
+ 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3,
+ 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61,
+ 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a,
+ 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40,
+ 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc,
+ 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5,
+ 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a,
+ 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d,
+ 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c,
+ 0xd8, 0xab, 0x4d, 0x9a, 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35,
+ 0x6a, 0xd4, 0xb3, 0x7d, 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4,
+ 0xd3, 0xbd, 0x61, 0xc2, 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc,
+ 0x83, 0x1d, 0x3a, 0x74, 0xe8, 0xcb, 0x8d, 0x01, 0x02, 0x04, 0x08,
+ 0x10, 0x20, 0x40, 0x80, 0x1b, 0x36, 0x6c, 0xd8, 0xab, 0x4d, 0x9a,
+ 0x2f, 0x5e, 0xbc, 0x63, 0xc6, 0x97, 0x35, 0x6a, 0xd4, 0xb3, 0x7d,
+ 0xfa, 0xef, 0xc5, 0x91, 0x39, 0x72, 0xe4, 0xd3, 0xbd, 0x61, 0xc2,
+ 0x9f, 0x25, 0x4a, 0x94, 0x33, 0x66, 0xcc, 0x83, 0x1d, 0x3a, 0x74,
+ 0xe8, 0xcb]
+
+ def __getSBoxValue(self, num):
+ """
+ Private method to retrieve a given S-Box value.
+
+ @param num position of the value (integer)
+ @return value of the S-Box (integer)
+ """
+ return self.sbox[num]
+
+ def __getSBoxInvert(self, num):
+ """
+ Private method to retrieve a given Inverted S-Box value.
+
+ @param num position of the value (integer)
+ @return value of the Inverted S-Box (integer)
+ """
+ return self.rsbox[num]
+
+ def __rotate(self, data):
+ """
+ Private method performing Rijndael's key schedule rotate operation.
+
+ Rotate the data word eight bits to the left: eg, rotate(1d2c3a4f) == 2c3a4f1d.
+
+ @param data data of size 4 (bytearray)
+ """
+ return data[1:] + data[:1]
+
+ def __getRconValue(self, num):
+ """
+ Private method to retrieve a given Rcon value.
+
+ @param num position of the value (integer)
+ @return Rcon value (integer)
+ """
+ return self.Rcon[num]
+
+ def __core(self, data, iteration):
+ """
+ Private method performing the key schedule core operation.
+
+ @param data data to operate on (bytearray)
+ @param iteration iteration counter (integer)
+ @return modified data (bytearray)
+ """
+ # rotate the 32-bit word 8 bits to the left
+ data = self.__rotate(data)
+ # apply S-Box substitution on all 4 parts of the 32-bit word
+ for i in range(4):
+ data[i] = self.__getSBoxValue(data[i])
+ # XOR the output of the rcon operation with i to the first part
+ # (leftmost) only
+ data[0] = data[0] ^ self.__getRconValue(iteration)
+ return data
+
+ def __expandKey(self, key, size, expandedKeySize):
+ """
+ Private method performing Rijndael's key expansion.
+
+ Expands a 128, 192 or 256 bit key into a 176, 208 or 240 bit key.
+
+ @param key key to be expanded (bytes or bytearray)
+ @param size size of the key in bytes (16, 24 or 32)
+ @param expandedKeySize size of the expanded key (integer)
+ @return expanded key (bytearray)
+ """
+ # current expanded keySize, in bytes
+ currentSize = 0
+ rconIteration = 1
+ expandedKey = bytearray(expandedKeySize)
+
+ # set the 16, 24, 32 bytes of the expanded key to the input key
+ for j in range(size):
+ expandedKey[j] = key[j]
+ currentSize += size
+
+ while currentSize < expandedKeySize:
+ # assign the previous 4 bytes to the temporary value t
+ t = expandedKey[currentSize - 4:currentSize]
+
+ # every 16, 24, 32 bytes we apply the core schedule to t
+ # and increment rconIteration afterwards
+ if currentSize % size == 0:
+ t = self.__core(t, rconIteration)
+ rconIteration += 1
+ # For 256-bit keys, we add an extra sbox to the calculation
+ if size == self.KeySize["SIZE_256"] and ((currentSize % size) == 16):
+ for l in range(4):
+ t[l] = self.__getSBoxValue(t[l])
+
+ # We XOR t with the four-byte block 16, 24, 32 bytes before the new
+ # expanded key. This becomes the next four bytes in the expanded key.
+ for m in range(4):
+ expandedKey[currentSize] = \
+ expandedKey[currentSize - size] ^ t[m]
+ currentSize += 1
+
+ return expandedKey
+
+ def __addRoundKey(self, state, roundKey):
+ """
+ Private method to add (XORs) the round key to the state.
+
+ @param state state to be changed (bytearray)
+ @param roundKey key to be used for the modification (bytearray)
+ @return modified state (bytearray)
+ """
+ buf = state[:]
+ for i in range(16):
+ buf[i] ^= roundKey[i]
+ return buf
+
+ def __createRoundKey(self, expandedKey, roundKeyPointer):
+ """
+ Private method to create a round key.
+
+ @param expandedKey expanded key to be used (bytearray)
+ @param roundKeyPointer position within the expanded key (integer)
+ @return round key (bytearray)
+ """
+ roundKey = bytearray(16)
+ for i in range(4):
+ for j in range(4):
+ roundKey[j * 4 + i] = expandedKey[roundKeyPointer + i * 4 + j]
+ return roundKey
+
+ def __galois_multiplication(self, a, b):
+ """
+ Private method to perform a Galois multiplication of 8 bit characters a and b.
+
+ @param a first factor (byte)
+ @param b second factor (byte)
+ @return result (byte)
+ """
+ p = 0
+ for counter in range(8):
+ if b & 1:
+ p ^= a
+ hi_bit_set = a & 0x80
+ a <<= 1
+ # keep a 8 bit
+ a &= 0xFF
+ if hi_bit_set:
+ a ^= 0x1b
+ b >>= 1
+ return p
+
+ def __subBytes(self, state, isInv):
+ """
+ Private method to substitute all the values from the state with the value in
+ the SBox using the state value as index for the SBox.
+
+ @param state state to be worked on (bytearray)
+ @param isInv flag indicating an inverse operation (boolean)
+ @return modified state (bytearray)
+ """
+ state = state[:]
+ if isInv:
+ getter = self.__getSBoxInvert
+ else:
+ getter = self.__getSBoxValue
+ for i in range(16):
+ state[i] = getter(state[i])
+ return state
+
+ def __shiftRows(self, state, isInv):
+ """
+ Private method to iterate over the 4 rows and call __shiftRow() with
+ that row.
+
+ @param state state to be worked on (bytearray)
+ @param isInv flag indicating an inverse operation (boolean)
+ @return modified state (bytearray)
+ """
+ state = state[:]
+ for i in range(4):
+ state = self.__shiftRow(state, i * 4, i, isInv)
+ return state
+
+ def __shiftRow(self, state, statePointer, nbr, isInv):
+ """
+ Private method to shift the bytes of a row to the left.
+
+ @param state state to be worked on (bytearray)
+ @param statePointer index into the state (integer)
+ @param nbr number of positions to shift (integer)
+ @param isInv flag indicating an inverse operation (boolean)
+ @return modified state (bytearray)
+ """
+ state = state[:]
+ for i in range(nbr):
+ if isInv:
+ state[statePointer:statePointer + 4] = \
+ state[statePointer + 3:statePointer + 4] + \
+ state[statePointer:statePointer + 3]
+ else:
+ state[statePointer:statePointer + 4] = \
+ state[statePointer + 1:statePointer + 4] + \
+ state[statePointer:statePointer + 1]
+ return state
+
+ def __mixColumns(self, state, isInv):
+ """
+ Private method to perform a galois multiplication of the 4x4 matrix.
+
+ @param state state to be worked on (bytearray)
+ @param isInv flag indicating an inverse operation (boolean)
+ @return modified state (bytearray)
+ """
+ state = state[:]
+ # iterate over the 4 columns
+ for i in range(4):
+ # construct one column by slicing over the 4 rows
+ column = state[i:i + 16:4]
+ # apply the __mixColumn on one column
+ column = self.__mixColumn(column, isInv)
+ # put the values back into the state
+ state[i:i + 16:4] = column
+
+ return state
+
+ # galois multiplication of 1 column of the 4x4 matrix
+ def __mixColumn(self, column, isInv):
+ """
+ Private method to perform a galois multiplication of 1 column the 4x4 matrix.
+
+ @param column column to be worked on (bytearray)
+ @param isInv flag indicating an inverse operation (boolean)
+ @return modified column (bytearray)
+ """
+ column = column[:]
+ if isInv:
+ mult = [14, 9, 13, 11]
+ else:
+ mult = [2, 1, 1, 3]
+ cpy = column[:]
+ g = self.__galois_multiplication
+
+ column[0] = g(cpy[0], mult[0]) ^ g(cpy[3], mult[1]) ^ \
+ 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
+
+ def __aes_round(self, state, roundKey):
+ """
+ Private method to apply the 4 operations of the forward round in sequence.
+
+ @param state state to be worked on (bytearray)
+ @param roundKey round key to be used (bytearray)
+ @return modified state (bytearray)
+ """
+ state = self.__subBytes(state, False)
+ state = self.__shiftRows(state, False)
+ state = self.__mixColumns(state, False)
+ state = self.__addRoundKey(state, roundKey)
+ return state
+
+ def __aes_invRound(self, state, roundKey):
+ """
+ Private method to apply the 4 operations of the inverse round in sequence.
+
+ @param state state to be worked on (bytearray)
+ @param roundKey round key to be used (bytearray)
+ @return modified state (bytearray)
+ """
+ state = self.__shiftRows(state, True)
+ state = self.__subBytes(state, True)
+ state = self.__addRoundKey(state, roundKey)
+ state = self.__mixColumns(state, True)
+ return state
+
+ def __aes_main(self, state, expandedKey, nbrRounds):
+ """
+ Private method to perform the initial operations, the standard round, and the
+ final operations of the forward AES, creating a round key for each round.
+
+ @param state state to be worked on (bytearray)
+ @param expandedKey expanded key to be used (bytearray)
+ @param nbrRounds number of rounds to be done (integer)
+ @return modified state (bytearray)
+ """
+ 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
+
+ def __aes_invMain(self, state, expandedKey, nbrRounds):
+ """
+ Private method to perform the initial operations, the standard round, and the
+ final operations of the inverse AES, creating a round key for each round.
+
+ @param state state to be worked on (bytearray)
+ @param expandedKey expanded key to be used (bytearray)
+ @param nbrRounds number of rounds to be done (integer)
+ @return modified state (bytearray)
+ """
+ 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
+
+ def encrypt(self, iput, key, size):
+ """
+ Public method to encrypt a 128 bit input block against the given key of size
+ specified.
+
+ @param iput input data (bytearray)
+ @param key key to be used (bytes or bytearray)
+ @param size key size (16, 24 or 32)
+ @return encrypted data (bytes)
+ """
+ output = bytearray(16)
+ # the number of rounds
+ nbrRounds = 0
+ # the 128 bit block to encode
+ block = bytearray(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:
+ raise ValueError("Wrong key size given ({0}).".format(size))
+
+ # 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 bytes(output)
+
+ # decrypts a 128 bit input block against the given key of size specified
+ def decrypt(self, iput, key, size):
+ """
+ Public method to decrypt a 128 bit input block against the given key of size
+ specified.
+
+ @param iput input data (bytearray)
+ @param key key to be used (bytes or bytearray)
+ @param size key size (16, 24 or 32)
+ @return decrypted data (bytes)
+ """
+ output = bytearray(16)
+ # the number of rounds
+ nbrRounds = 0
+ # the 128 bit block to decode
+ block = bytearray(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:
+ raise ValueError("Wrong key size given ({0}).".format(size))
+
+ # 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):
+ """
+ Class implementing the different AES mode of operations.
+ """
+ aes = AES()
+
+ # structure of supported modes of operation
+ ModeOfOperation = {
+ "OFB": 0,
+ "CFB": 1,
+ "CBC": 2,
+ }
+
+ def __extractBytes(self, input, start, end, mode):
+ """
+ Private method to extract a range of bytes from the input.
+
+ @param input input data (bytes)
+ @param start start index (integer)
+ @param end end index (integer)
+ @param mode mode of operation (0, 1, 2)
+ @return extracted bytes (bytearray)
+ """
+ if end - start > 16:
+ end = start + 16
+ if mode == self.ModeOfOperation["CBC"]:
+ ar = bytearray(16)
+ else:
+ ar = bytearray()
+
+ i = start
+ j = 0
+ while len(ar) < end - start:
+ ar.append(0)
+ while i < end:
+ ar[j] = input[i]
+ j += 1
+ i += 1
+ return ar
+
+ def encrypt(self, input, mode, key, size, IV):
+ """
+ Public method to perform the encryption operation.
+
+ @param input data to be encrypted (bytes)
+ @param mode mode of operation (0, 1 or 2)
+ @param key key to be used (bytes)
+ @param size length of the key (integer)
+ @param IV initialisation vector (bytearray)
+ @return tuple with mode of operation, length of the input and
+ the encrypted data (integer, integer, bytes)
+ """
+ if len(key) % size:
+ raise ValueError("Illegal size ({0}) for key '{1}'.".format(
+ size, key))
+ if len(IV) % 16:
+ raise ValueError("IV is not a multiple of 16.")
+ # the AES input/output
+ iput = bytearray(16)
+ output = bytearray()
+ ciphertext = bytearray(16)
+ # the output cipher string
+ cipherOut = bytearray()
+ # char firstRound
+ firstRound = True
+ if input:
+ for j in range(int(math.ceil(float(len(input)) / 16))):
+ start = j * 16
+ end = j * 16 + 16
+ if end > len(input):
+ end = len(input)
+ plaintext = self.__extractBytes(input, 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(input), bytes(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):
+ """
+ Public method to perform the decryption operation.
+
+ @param input data to be encrypted (bytes)
+ @param originalsize unencrypted string length (required for CBC)
+ (integer)
+ @param mode mode of operation (0, 1 or 2)
+ @param key key to be used (bytes)
+ @param size length of the key (integer)
+ @param IV initialisation vector (bytearray)
+ @return decrypted data (bytes)
+ """
+ if len(key) % size:
+ raise ValueError("Illegal size ({0}) for key '{1}'.".format(
+ size, key))
+ if len(IV) % 16:
+ raise ValueError("IV is not a multiple of 16.")
+ # the AES input/output
+ ciphertext = bytearray()
+ iput = bytearray()
+ output = bytearray()
+ plaintext = bytearray(16)
+ # the output bytes
+ bytesOut = bytearray()
+ # 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):
+ bytesOut.append(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):
+ bytesOut.append(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):
+ bytesOut.append(plaintext[k])
+ else:
+ for k in range(end - start):
+ bytesOut.append(plaintext[k])
+ iput = ciphertext
+ return bytes(bytesOut)
+
+
+def encryptData(key, data, mode=AESModeOfOperation.ModeOfOperation["CBC"]):
+ """
+ Module function to encrypt the given data with the given key.
+
+ @param key key to be used for encryption (bytes)
+ @param data data to be encrypted (bytes)
+ @param mode mode of operations (0, 1 or 2)
+ @return encrypted data prepended with the initialization vector (bytes)
+ """
+ key = bytearray(key)
+ if mode == AESModeOfOperation.ModeOfOperation["CBC"]:
+ data = append_PKCS7_padding(data)
+ keysize = len(key)
+ assert keysize in AES.KeySize.values(), 'invalid key size: {0}'.format(keysize)
+ # create a new iv using random data
+ iv = bytearray([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 bytes(iv) + bytes(ciph)
+
+
+def decryptData(key, data, mode=AESModeOfOperation.ModeOfOperation["CBC"]):
+ """
+ Module function to decrypt the given data with the given key.
+
+ @param key key to be used for decryption (bytes)
+ @param data data to be decrypted (with initialization vector prepended) (bytes)
+ @param mode mode of operations (0, 1 or 2)
+ @return decrypted data (bytes)
+ @exception ValueError key size is invalid or decrypted data is invalid
+ """
+ key = bytearray(key)
+ keysize = len(key)
+ assert keysize in AES.KeySize.values(), 'invalid key size: %s' % keysize
+ # iv is first 16 bytes
+ iv = bytearray(data[:16])
+ data = bytearray(data[16:])
+ moo = AESModeOfOperation()
+ decr = moo.decrypt(data, None, mode, key, keysize, iv)
+ if mode == AESModeOfOperation.ModeOfOperation["CBC"]:
+ decr = strip_PKCS7_padding(decr)
+ return bytes(decr)
