eric: comparison Utilities/crypto/py3AES.py

-:4ed80ed7e433
+:b1802ebe0066
+#!/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)

Mercurial Repositories > eric / file comparison

comparison: Utilities/crypto/py3AES.py

Utilities/crypto/py3AES.py