src/Cipher/python_DES3.py

   1 import blockcipher
   2 import pyDes
   3
   4 MODE_ECB = 1
   5 MODE_CBC = 2
   6 MODE_CFB = 3
   7 MODE_OFB = 5
   8 MODE_CTR = 6
   9 MODE_CMAC = 8
  10
  11 def new(key,mode=blockcipher.MODE_ECB,IV=None,counter=None):
  12         """Create a DES-EDE3 or DES-EDE2 cipher object
  13
  14         wrapper for pure python 3DES implementation pyDes.py
  15
  16         new(key,mode=blockcipher.MODE_ECB,IV=None,counter=None):
  17                 key = raw string containing the 2/3 keys
  18                         - DES-EDE2: supply 2 keys as 1 single concatenated 16byte key= key1|key2
  19                         - DES-EDE3: supply 3 keys as 1 single concatenated 24byte key= key1|key2|key3
  20                 mode = python_AES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC
  21                 IV = IV as a raw string
  22                         -> only needed for CBC mode
  23                 counter = counter object (Cipher/util.py:Counter)
  24                         -> only needed for CTR mode
  25
  26         CBC TDES-EDE3 EXAMPLE: (using test vectors from http://csrc.nist.gov/groups/STM/cavp/documents/des/DESMMT.pdf)
  27         ------------
  28         >>> import python_DES3
  29         >>> from binascii import hexlify, unhexlify
  30         >>> key = unhexlify('37ae5ebf46dff2dc0754b94f31cbb3855e7fd36dc870bfae')
  31         >>> IV = unhexlify('3d1de3cc132e3b65')
  32         >>> cipher = python_DES3.new(key, python_DES3.MODE_CBC, IV)
  33         >>> ciphertext = cipher.encrypt(unhexlify('84401f78fe6c10876d8ea23094ea5309'))
  34         >>> hexlify(ciphertext)
  35         '7b1f7c7e3b1c948ebd04a75ffba7d2f5'
  36         >>> decipher = python_DES3.new(key, python_DES3.MODE_CBC, IV)
  37         >>> plaintext = decipher.decrypt(ciphertext)
  38         >>> hexlify(plaintext)
  39         '84401f78fe6c10876d8ea23094ea5309'
  40
  41         CMAC TDES-EDE3 EXAMPLE:
  42         -------------
  43         testvector: http://csrc.nist.gov/publications/nistpubs/800-38B/Updated_CMAC_Examples.pdf
  44
  45         >>> key = '8aa83bf8cbda10620bc1bf19fbb6cd58bc313d4a371ca8b5'.decode('hex')
  46         >>> plaintext = '6bc1bee22e409f96e93d7e117393172aae2d8a57'.decode('hex')
  47         >>> cipher = python_DES3.new(key, python_DES3.MODE_CMAC)
  48         >>> cipher.encrypt(plaintext).encode('hex')
  49         '743ddbe0ce2dc2ed'
  50
  51         CMAC TDES-EDE2 EXAMPLE:
  52         -----------------------
  53         testvector: http://csrc.nist.gov/groups/STM/cavp/documents/mac/cmactestvectors.zip
  54
  55         >>> key1 = "5104f2c76180c1d3".decode('hex')
  56         >>> key2 = "b9df763e31ada716".decode('hex')
  57         >>> key = key1 + key2
  58         >>> plaintext = 'a6866be2fa6678f264a19c4474968e3f4eec24f5086d'.decode('hex')
  59         >>> cipher = python_DES3.new(key, python_DES3.MODE_CMAC)
  60         >>> cipher.encrypt(plaintext).encode('hex')
  61         '32e7758f3f614dbf'"""
  62         return python_DES3(key,mode,IV,counter)
  63
  64 class python_DES3(blockcipher.BlockCipher):
  65         def __init__(self,key,mode,IV,counter):
  66                 assert len(key) in (16,24)
  67                 self.cipher = pyDes.triple_des(key)
  68                 self.blocksize = self.cipher.block_size
  69                 blockcipher.BlockCipher.__init__(self,key,mode,IV,counter)
  70
  71 def _test():
  72         import doctest
  73         doctest.testmod()
  74
  75 if __name__ == "__main__":
  76         _test()