| 0,0 → 1,84 |
|---|
| """ crypto.cipher.trolldoll |
| |
| Modification to Icedoll to take advantage of the better error extension |
| and provide a IV for randomization of the output and integrity checking. |
| |
| IV is simply prepended to plaintext. |
| Integrity check is appended to the end of the plain text as |
| zeros with count of the blocks in the ciphertext. |
| |
| Note !!!! auto IV uses python default random :-( |
| should not be 'too bad' (tm) for this applicaiton |
| |
| ALso ... currently just IV .... in test .. |
| |
| Copyright © (c) 2002 by Paul A. Lambert |
| Read LICENSE.txt for license information. |
| """ |
| |
| from crypto.cipher.icedoll import Icedoll |
| from crypto.errors import IntegrityCheckError |
| from random import Random # should change to crypto.random!!! |
| |
| class Trolldoll(Icedoll): |
| """ Trolldoll encryption algorithm |
| based on Icedoll, which is based on Rijndael |
| Trolldoll adds an 'IV' and integrity checking to Icedoll |
| """ |
| def __init__(self,key=None,keySize=32,blockSize=32,tapRound=6,extraRounds=6,micSize=16,ivSize=16): |
| """ """ |
| Icedoll.__init__(self,key=None,keySize=32,blockSize=32,tapRound=6,extraRounds=6) |
| self.name = 'TROLLDOLL' |
| self.micSize = micSize |
| self.ivSize = ivSize |
| self.r = Random() # for IV generation |
| import time |
| newSeed = time.ctime()+str(self.r) # seed with instance location |
| self.r.seed(newSeed) # to make unique |
| self.reset() |
| |
| def reset(self): |
| Icedoll.reset(self) |
| self.hasIV = None |
| |
| def _makeIV(self): |
| return self.ivSize*'a' |
| |
| def _makeIC(self): |
| """ Make the integrity check """ |
| return self.micSize*chr(0x00) |
| |
| def _verifyIC(self,integrityCheck): |
| """ Verify the integrity check """ |
| if self.micSize*chr(0x00) == integrityCheck : |
| return 1 # matches |
| else: |
| return 0 # fails |
| |
| def encrypt(self, plainText, more=None): |
| """ """ |
| if not(self.hasIV): # On first call to encrypt put in an IV |
| plainText = self._makeIV() + plainText # add the 'IV' |
| self.hasIV = 1 |
| if more == None: # on last call to encrypt append integrity check |
| plainText = plainText + self._makeIC() |
| return Icedoll.encrypt(self, plainText, more=more) |
| |
| def decrypt(self, cipherText, more=None): |
| """ Decrypt cipher text, Icedoll automatically removes |
| prepended random bits used as IV. |
| Note - typically IV is directly used as the first |
| cipher text. Here the IV is prepended to the plaintext |
| prior to encryption and removed on decryption. |
| """ |
| plainText = Icedoll.decrypt(self, cipherText, more=more) |
| if not(self.hasIV): # on first call to decrypt remove IV |
| plainText = plainText[self.ivSize:] # remove the IV |
| self.hasIV = 1 |
| if more == None: # on last call to encrypt append integrity check |
| if not(self._verifyIC(plainText[-self.micSize:])) : |
| raise IntegrityCheckError, 'Trolldoll MIC Failure, bad key or modified data' |
| plainText = plainText[:-self.micSize] # trim off the integrity check |
| return plainText |
| |
| |