DeDRM_tools/Calibre_Plugins/eReaderPDB2PML_plugin/pycrypto_des.py

31 lines
853 B
Python

#!/usr/bin/env python
# vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab
def load_pycrypto():
try :
from Crypto.Cipher import DES as _DES
except:
return None
class DES(object):
def __init__(self, key):
if len(key) != 8 :
raise Error('DES improper key used')
self.key = key
self._des = _DES.new(key,_DES.MODE_ECB)
def desdecrypt(self, data):
return self._des.decrypt(data)
def decrypt(self, data):
if not data:
return ''
i = 0
result = []
while i < len(data):
block = data[i:i+8]
processed_block = self.desdecrypt(block)
result.append(processed_block)
i += 8
return ''.join(result)
return DES