| 0,0 → 1,102 |
|---|
| """ crypto.cipher.icedoll |
| |
| Modification of Rijndael to provide infinite error extension. |
| The ith round of Rijndael is tapped and used to process the |
| subsequent block. |
| |
| Changes to base Rijndael are marked with: '# --------------------------' |
| |
| For Rijndael with N rounds, normally ECB mode is C[i] = Ek(N,P[i]) |
| |
| Modification is: |
| Fi = Ek(t,P[i-1]) ; Fi, with i=0 is nonce or a fixed value |
| C[i] = Fi^Ek(N,P[i]^Fi) |
| |
| Copyright © (c) 2002 by Paul A. Lambert |
| Read LICENSE.txt for license information. |
| |
| June 2002 |
| February 2003 -> discovered Ron Rivest's "Tweakable Block Ciphers" |
| http://theory.lcs.mit.edu/~rivest/publications.html |
| These are about the same concept .... |
| """ |
| |
| from crypto.cipher.base import BlockCipherWithIntegrity, padWithPadLen, noPadding |
| from crypto.cipher.rijndael import * |
| from binascii_plus import b2a_hex |
| from copy import deepcopy |
| |
| class Icedoll(Rijndael): |
| """ IceDoll encryption algorithm |
| based on Rijndael, with added feedback for better integrity processing. |
| Note - no integrity check is built into Icedoll directly |
| """ |
| def __init__(self,key=None,padding=padWithPadLen(),keySize=16,blockSize=16,tapRound=6,extraRounds=6): |
| """ key, keysize, blockSize same as Rijndael, tapROund is feedback tap, """ |
| self.tapRound = tapRound # <------- !!! change from Rijndael !!! |
| self.extraRounds = extraRounds # <------- !!! change from Rijndael !!! |
| self.name = 'ICEDOLL' |
| self.keySize = keySize |
| self.strength = keySize |
| self.blockSize = blockSize # blockSize is in bytes |
| self.padding = padding # change default to noPadding() to get normal ECB behavior |
| |
| assert( keySize%4==0 and NrTable[4].has_key(keySize/4)),'key size must be 16,20,24,29 or 32 bytes' |
| assert( blockSize%4==0 and NrTable.has_key(blockSize/4)), 'block size must be 16,20,24,29 or 32 bytes' |
| |
| self.Nb = self.blockSize/4 # Nb is number of columns of 32 bit words |
| self.Nk = keySize/4 # Nk is the key length in 32-bit words |
| self.Nr = NrTable[self.Nb][self.Nk]+extraRounds # <------- !!! change from Rijndael !!! |
| |
| if key != None: |
| self.setKey(key) |
| |
| def setKey(self, key): |
| """ Set a key and generate the expanded key """ |
| assert( len(key) == (self.Nk*4) ), 'Key length must be same as keySize parameter' |
| self.__expandedKey = keyExpansion(self, key) |
| self.reset() # BlockCipher.reset() |
| |
| def encryptBlock(self, plainTextBlock): |
| """ Encrypt a block, plainTextBlock must be a array of bytes [Nb by 4] """ |
| self.state = self._toBlock(plainTextBlock) |
| if self.encryptBlockCount == 0: # first call, set frdd back |
| self.priorFeedBack = self._toBlock(chr(0)*(4*self.Nb)) # <------- !!! change from Rijndael !!! |
| AddRoundKey(self, self.priorFeedBack) # <------- !!! change from Rijndael !!! |
| AddRoundKey(self, self.__expandedKey[0:self.Nb]) |
| for round in range(1,self.Nr): #for round = 1 step 1 to Nr1 |
| SubBytes(self) |
| ShiftRows(self) |
| MixColumns(self) |
| if round == self.tapRound: |
| nextFeedBack = deepcopy(self.state) # <------- !!! change from Rijndael !!! |
| AddRoundKey(self, self.__expandedKey[round*self.Nb:(round+1)*self.Nb]) |
| SubBytes(self) |
| ShiftRows(self) |
| AddRoundKey(self, self.__expandedKey[self.Nr*self.Nb:(self.Nr+1)*self.Nb]) |
| AddRoundKey(self, self.priorFeedBack) # <------- !!! change from Rijndael !!! |
| self.priorFeedBack = nextFeedBack # <------- !!! change from Rijndael !!! |
| return self._toBString(self.state) |
| |
| def decryptBlock(self, encryptedBlock): |
| """ decrypt a block (array of bytes) """ |
| self.state = self._toBlock(encryptedBlock) |
| if self.decryptBlockCount == 0: # first call, set frdd back |
| self.priorFeedBack = self._toBlock( chr(0)*(4*self.Nb) ) # <------- !!! change from Rijndael !!! |
| AddRoundKey(self, self.priorFeedBack) # <------- !!! change from Rijndael !!! |
| AddRoundKey(self, self.__expandedKey[self.Nr*self.Nb:(self.Nr+1)*self.Nb]) |
| for round in range(self.Nr-1,0,-1): |
| InvShiftRows(self) |
| InvSubBytes(self) |
| AddRoundKey(self, self.__expandedKey[round*self.Nb:(round+1)*self.Nb]) |
| if round == self.tapRound: |
| nextFeedBack = deepcopy(self.state) # <------- !!! change from Rijndael !!! |
| InvMixColumns(self) |
| InvShiftRows(self) |
| InvSubBytes(self) |
| AddRoundKey(self, self.__expandedKey[0:self.Nb]) |
| AddRoundKey(self, self.priorFeedBack) # <------- !!! change from Rijndael !!! |
| self.priorFeedBack = nextFeedBack # <------- !!! change from Rijndael !!! |
| return self._toBString(self.state) |
| |
| |