Author:   Todd Whiteman
Version:  2.0.1
Release:  28th April, 2010
License:  MIT

$ python setup.py install

$ python test_pydes.py

Class initialization
--------------------
pyDes.des(key, [mode], [IV], [pad], [padmode])
pyDes.triple_des(key, [mode], [IV], [pad], [padmode])

key     -> Bytes containing the encryption key. 8 bytes for DES, 16 or 24 bytes
	   for Triple DES
mode    -> Optional argument for encryption type, can be either
	   pyDes.ECB (Electronic Code Book) or pyDes.CBC (Cypher Block Chaining)
IV      -> Optional Initial Value bytes, must be supplied if using CBC mode.
	   Length must be 8 bytes.
pad     -> Optional argument, set the pad character (PAD_NORMAL) to use during
	   all encrypt/decrpt operations done with this instance.
padmode -> Optional argument, set the padding mode (PAD_NORMAL or PAD_PKCS5)
	   to use during all encrypt/decrypt operations done with this instance.

I recommend to use PAD_PKCS5 padding, as then you never need to worry about any
padding issues, as the padding can be removed unambiguously upon decrypting
data that was encrypted using PAD_PKCS5 padmode.

Common methods
--------------
encrypt(data, [pad], [padmode])
decrypt(data, [pad], [padmode])

data    -> Bytes to be encrypted/decrypted
pad     -> Optional argument. Only when using padmode of PAD_NORMAL. For
	   encryption, adds this characters to the end of the data block when
	   data is not a multiple of 8 bytes. For decryption, will remove the
	   trailing characters that match this pad character from the last 8
	   bytes of the unencrypted data block.
padmode -> Optional argument, set the padding mode, must be one of PAD_NORMAL
	   or PAD_PKCS5). Defaults to PAD_NORMAL.
	  

Example
-------
import pyDes

# For Python3, you'll need to use bytes, i.e.:
#   data = b"Please encrypt my data"
#   k = pyDes.des(b"DESCRYPT", pyDes.CBC, b"\0\0\0\0\0\0\0\0", pad=None, padmode=pyDes.PAD_PKCS5)

data = "Please encrypt my data"
k = pyDes.des("DESCRYPT", pyDes.CBC, "\0\0\0\0\0\0\0\0", pad=None, padmode=pyDes.PAD_PKCS5)
d = k.encrypt(data)
print "Encrypted: %r" % d
print "Decrypted: %r" % k.decrypt(d)
assert k.decrypt(d) == data


See the pyDes test file (test_pydes.py) for more examples of use.

Note: This code was not written for high-end systems needing a fast
      implementation, but rather a handy portable solution with small usage.