src/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):
   5     """Create a new cipher object
   6
   7     Wrapper for pure python implementation rijndael.py
   8
   9     new(key,mode=MODE_ECB,IV=None,counter=None,rounds=32):
  10         key = raw string containing the key, AES-128..256 will be selected according to the key length
  11             -> when using XTS mode: the key should be a tuple containing the 2 keys needed
  12         mode = python_PRESENT.MODE_ECB/CBC/CFB/OFB/CTR/XTS/CMAC, default is ECB
  13             -> for every mode, except ECB and CTR, it is important to construct a seperate cipher for encryption and decryption
  14         IV = IV as a raw string
  15             -> needed for CBC, CFB and OFB mode
  16         counter = counter object (CryptoPlus.Util.util.Counter)
  17             -> only needed for CTR mode
  18             -> use a seperate counter object for the cipher and decipher: the counter is updated directly, not a copy
  19                 see CTR example further on in the docstring
  20                 rounds = amount of rounds
  21
  22     Notes:
  23         - Always construct a seperate cipher object for encryption and decryption. Once a cipher object has been used for encryption,
  24           it can't be used for decryption because it keeps a state (if necessary) for the IV.
  25
  26
  27         ECB Test Vectors:
  28         ------------------
  29         >>> from CryptoPlus.Cipher import python_PRESENT
  30
  31         >>> key = "00000000000000000000".decode('hex')
  32         >>> plain = "0000000000000000".decode('hex')
  33         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB)
  34         >>> cipher.encrypt(plain).encode('hex')
  35         '5579c1387b228445'
  36
  37         >>> key = "00000000000000000000000000000000".decode('hex')
  38         >>> plain = "0000000000000000".decode('hex')
  39         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=64)
  40         >>> cipher.encrypt(plain).encode('hex')
  41         '67d38fb0f5a371fd'
  42
  43         >>> key = "00000000000000000000".decode('hex')
  44         >>> plain = "0000000000000000".decode('hex')
  45         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=64)
  46         >>> cipher.encrypt(plain).encode('hex')
  47         '13991dd588bc1288'
  48
  49         Test Vectors for maximum rounds supported by PRESENT reference C code:
  50         -----------------------------------------------------------------------
  51         >>> key = "0123456789abcdef0123".decode('hex')
  52         >>> plain = "0123456789abcdef".decode('hex')
  53         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=65534)
  54         >>> ciphertext = cipher.encrypt(plain)
  55         >>> ciphertext.encode('hex')
  56         'a140dc5d7175ca20'
  57         >>> cipher.decrypt(ciphertext).encode('hex')
  58         '0123456789abcdef'
  59
  60         >>> key = "0123456789abcdef0123456789abcdef".decode('hex')
  61         >>> plain = "0123456789abcdef".decode('hex')
  62         >>> cipher = python_PRESENT.new(key,python_PRESENT.MODE_ECB,rounds=65534)
  63         >>> ciphertext = cipher.encrypt(plain)
  64         >>> ciphertext.encode('hex')
  65         'c913bc146bc89c4e'
  66         >>> cipher.decrypt(ciphertext).encode('hex')
  67         '0123456789abcdef'
  68         """
  69     return python_PRESENT(key,mode,IV,counter,rounds)
  70
  71 class python_PRESENT(BlockCipher):
  72     def __init__(self,key,mode,IV,counter,rounds):
  73         self.cipher = Present(key,rounds)
  74         self.blocksize = 8
  75         BlockCipher.__init__(self,key,mode,IV,counter)
  76
  77 def _test():
  78     import doctest
  79     doctest.testmod()
  80
  81 if __name__ == "__main__":
  82     _test()