src/CryptoPlus/Cipher/python_DES3.py

   1 from blockcipher import *
   2 import pyDes
   3
   4 def new(key,mode=MODE_ECB,IV=None,counter=None,segment_size=None):
   5     """Create a DES-EDE3 or DES-EDE2 cipher object
   6
   7     wrapper for pure python 3DES implementation pyDes.py
   8
   9         key = raw string containing the 2/3 keys
  10             - DES-EDE2: supply 2 keys as 1 single concatenated 16byte key= key1|key2
  11             - DES-EDE3: supply 3 keys as 1 single concatenated 24byte key= key1|key2|key3
  12         mode = python_AES.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
  13         IV = IV as a raw string, default is "all zero" IV
  14             -> only needed for CBC mode
  15         counter = counter object (CryptoPlus.Util.util.Counter)
  16             -> only needed for CTR mode
  17         segment_size = amount of bits to use from the keystream in each chain part
  18             -> supported values: multiple of 8 between 8 and the blocksize
  19                of the cipher (only per byte access possible), default is 8
  20             -> only needed for CFB mode
  21
  22     EXAMPLES:
  23     **********
  24     IMPORTING:
  25     -----------
  26     >>> from CryptoPlus.Cipher import python_DES3
  27
  28     CBC TDES-EDE3 EXAMPLE: (using test vectors from http://csrc.nist.gov/groups/STM/cavp/documents/des/DESMMT.pdf)
  29     ------------
  30     >>> key = ('37ae5ebf46dff2dc0754b94f31cbb3855e7fd36dc870bfae').decode('hex')
  31     >>> IV = ('3d1de3cc132e3b65').decode('hex')
  32     >>> cipher = python_DES3.new(key, python_DES3.MODE_CBC, IV)
  33     >>> ciphertext = cipher.encrypt(('84401f78fe6c10876d8ea23094ea5309').decode('hex'))
  34     >>> (ciphertext).encode('hex')
  35     '7b1f7c7e3b1c948ebd04a75ffba7d2f5'
  36     >>> decipher = python_DES3.new(key, python_DES3.MODE_CBC, IV)
  37     >>> plaintext = decipher.decrypt(ciphertext)
  38     >>> (plaintext).encode('hex')
  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,segment_size)
  63
  64 class python_DES3(BlockCipher):
  65     key_error_message = "Key should be 128 or 192 bits"
  66
  67     def __init__(self,key,mode,IV,counter,segment_size):
  68         cipher_module = pyDes.triple_des
  69         self.blocksize = 8
  70         BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size)
  71
  72     def keylen_valid(self,key):
  73         return len(key) in (16,24)
  74
  75 def _test():
  76     import doctest
  77     doctest.testmod()
  78
  79 if __name__ == "__main__":
  80     _test()