| 0,0 → 1,62 |
|---|
| """ crypto.entropy.prn_rijndael |
| |
| A Psudeo Random Number Generator based on Rijndael_256k_256b |
| The algorithm is based on Section 13.4 of: |
| "AES Proposal: Rijndael", Joan Daemen, Vincent Rijmen |
| |
| Copyright © (c) 2002 by Paul A. Lambert |
| Read LICENSE.txt for license information. |
| """ |
| |
| from crypto.cipher.rijndael import Rijndael |
| from crypto.cipher.base import noPadding |
| from binascii import b2a_hex |
| |
| defaultSeed = "An arbirary 32 byte string!!!!!!" # can be changed by the truely paranoid |
| |
| class PRN_Rijndael: |
| """ A Psudeo Random Number Generator based on Rijndael_256k_256b |
| The algorithm is based on Section 13.4 of: |
| "AES Proposal: Rijndael", Joan Daemen, Vincent Rijmen |
| """ |
| def __init__(self, seed=defaultSeed): |
| self.__algorithm = Rijndael(padding=noPadding(),keySize=32, blockSize=32) |
| self.reset() |
| self.reseed(seed) |
| |
| def reset(self): |
| self.__algorithm.setKey(self.__algorithm.keySize*chr(0)) # set key to all zeros |
| self.__state = self.__algorithm.blockSize*chr(0) # a single block of zeros |
| |
| def reseed(self,seed): |
| while len(seed) > 0 : |
| if len(seed) < self.__algorithm.blockSize: |
| block = seed + (self.__algorithm.blockSize-len(seed))*chr(0) |
| seed = '' |
| else: |
| block = seed[:self.__algorithm.blockSize] |
| seed = seed[self.__algorithm.blockSize:] |
| self.__algorithm.setKey( self.__algorithm.encrypt(block) ) |
| |
| def getBytes(self, numBytes): |
| """ Return a psuedo random byte string of length numBytes """ |
| bytes = '' |
| while len(bytes)< numBytes : |
| bytes = bytes + self.getSomeBytes() |
| return bytes[:numBytes] # truncate to the requested length |
| |
| def getSomeBytes(self): |
| """ Psuedo random bytes are generated 16 bytes at a time. |
| The state is updated by applying Rijndael using the Cipher |
| Key. The first 128 bits of the state are output as a pseudorandom number. |
| """ |
| self.__state = self.__algorithm.encrypt(self.__state) |
| return self.__state[:16] |
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