--- a/Utilities/crypto/py3AES.py Tue Oct 08 19:52:11 2013 +0200
+++ b/Utilities/crypto/py3AES.py Wed Oct 09 18:34:30 2013 +0200
@@ -6,7 +6,8 @@
# 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 )
+# 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/
@@ -46,10 +47,12 @@
@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)))
+ 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]))
+ raise ValueError(
+ "Data ending with {0} can't be PCKS7-padded".format(b[-1]))
return b[:-numpads]
@@ -164,7 +167,8 @@
"""
Private method performing Rijndael's key schedule rotate operation.
- Rotate the data word eight bits to the left: eg, rotate(1d2c3a4f) == 2c3a4f1d.
+ Rotate the data word eight bits to the left: eg,
+ rotate(1d2c3a4f) == 2c3a4f1d.
@param data data of size 4 (bytearray)
"""
@@ -228,12 +232,14 @@
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):
+ 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.
+ # expanded key. This becomes the next four bytes in the expanded
+ # key.
for m in range(4):
expandedKey[currentSize] = \
expandedKey[currentSize - size] ^ t[m]
@@ -270,7 +276,8 @@
def __galois_multiplication(self, a, b):
"""
- Private method to perform a Galois multiplication of 8 bit characters a and 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)
@@ -291,8 +298,8 @@
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.
+ 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)
@@ -366,7 +373,8 @@
# 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.
+ 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)
@@ -392,7 +400,8 @@
def __aes_round(self, state, roundKey):
"""
- Private method to apply the 4 operations of the forward round in sequence.
+ 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)
@@ -406,7 +415,8 @@
def __aes_invRound(self, state, roundKey):
"""
- Private method to apply the 4 operations of the inverse round in sequence.
+ 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)
@@ -420,15 +430,19 @@
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.
+ Private method to do the AES encryption for one round.
+
+ 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))
+ state = self.__addRoundKey(
+ state, self.__createRoundKey(expandedKey, 0))
i = 1
while i < nbrRounds:
state = self.__aes_round(
@@ -442,8 +456,11 @@
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.
+ Private method to do the inverse AES encryption for one round.
+
+ 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)
@@ -459,13 +476,14 @@
i -= 1
state = self.__shiftRows(state, True)
state = self.__subBytes(state, True)
- state = self.__addRoundKey(state, self.__createRoundKey(expandedKey, 0))
+ 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.
+ 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)
@@ -520,8 +538,8 @@
# 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.
+ 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)
@@ -801,7 +819,8 @@
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)
+ 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()
@@ -817,7 +836,8 @@
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 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
