src/CryptoPlus/Cipher/python_PRESENT.py

   1 from blockcipher import *
   2 from pypresent import Present
   3
   4 def new(key,mode=MODE_ECB,IV=None,counter=None,rounds=32,segment_size=8):
   5     """Create a new cipher object
   6
   7     Wrapper for pure python implementation rijndael.py
   8
   9         key = raw string containing the key, AES-128..256 will be selected according to the key length
  10         mode = python_PRESENT.MODE_ECB/CBC/CFB/OFB/CTR/CMAC, default is ECB
  11             -> for every mode, except ECB and CTR, it is important to construct a seperate cipher for encryption and decryption
  12         IV = IV as a raw string, default is "all zero" IV
  13             -> needed for CBC, CFB and OFB mode
  14         counter = counter object (CryptoPlus.Util.util.Counter)
  15             -> only needed for CTR mode
  16             -> use a seperate counter object for the cipher and decipher: the counter is updated directly, not a copy
  17                 see CTR example further on in the docstring
  18                 rounds = amount of rounds
  19         rounds = amount of rounds, default = 32
  20
  21     Notes:
  22         - Always construct a seperate cipher object for encryption and decryption. Once a cipher object has been used for encryption,
  23           it can't be used for decryption because it keeps a state (if necessary) for the IV.
  24
  25         EXAMPLES:
  26         **********
  27         IMPORTING:
  28         -----------
  29         >>> from CryptoPlus.Cipher import python_PRESENT
  30
  31         ECB Test Vectors:
  32         ------------------
  33         >>> key = "00000000000000000000".decode('hex')
  34         >>> plain = "0000000000000000".decode('hex')
  35         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB)
  36         >>> cipher.encrypt(plain).encode('hex')
  37         '5579c1387b228445'
  38
  39         >>> key = "00000000000000000000000000000000".decode('hex')
  40         >>> plain = "0000000000000000".decode('hex')
  41         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=64)
  42         >>> cipher.encrypt(plain).encode('hex')
  43         '59a27d01607ebf05'
  44
  45         >>> key = "00000000000000000000".decode('hex')
  46         >>> plain = "0000000000000000".decode('hex')
  47         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=64)
  48         >>> cipher.encrypt(plain).encode('hex')
  49         '13991dd588bc1288'
  50
  51         Test Vectors for maximum rounds supported by PRESENT reference C code:
  52         -----------------------------------------------------------------------
  53         >>> key = "0123456789abcdef0123".decode('hex')
  54         >>> plain = "0123456789abcdef".decode('hex')
  55         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=65534)
  56         >>> ciphertext = cipher.encrypt(plain)
  57         >>> ciphertext.encode('hex')
  58         'a140dc5d7175ca20'
  59         >>> cipher.decrypt(ciphertext).encode('hex')
  60         '0123456789abcdef'
  61
  62         >>> key = "0123456789abcdef0123456789abcdef".decode('hex')
  63         >>> plain = "0123456789abcdef".decode('hex')
  64         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=65534)
  65         >>> ciphertext = cipher.encrypt(plain)
  66         >>> ciphertext.encode('hex')
  67         '21007772e5d4ef14'
  68         >>> cipher.decrypt(ciphertext).encode('hex')
  69         '0123456789abcdef'
  70         """
  71     return python_PRESENT(key,mode,IV,counter,rounds,segment_size)
  72
  73 class python_PRESENT(BlockCipher):
  74     key_error_message = "Key should be 80 or 128 bits"
  75
  76     def __init__(self,key,mode,IV,counter,rounds,segment_size):
  77         cipher_module = Present
  78         args = {'rounds':rounds}
  79         self.blocksize = 8
  80         BlockCipher.__init__(self,key,mode,IV,counter,cipher_module,segment_size,args)
  81
  82     def keylen_valid(self,key):
  83         return len(key) in (10,16)
  84
  85 def _test():
  86     import doctest
  87     doctest.testmod()
  88
  89 if __name__ == "__main__":
  90     _test()