90 lines
3.0 KiB
Python
90 lines
3.0 KiB
Python
#!/usr/bin/env python
|
|
# vim:ts=4:sw=4:softtabstop=4:smarttab:expandtab
|
|
|
|
# implement just enough of des from openssl to make erdr2pml.py happy
|
|
|
|
def load_libcrypto():
|
|
from ctypes import CDLL, POINTER, c_void_p, c_char_p, c_char, c_int, c_long, \
|
|
Structure, c_ulong, create_string_buffer, cast
|
|
from ctypes.util import find_library
|
|
import sys
|
|
|
|
if sys.platform.startswith('win'):
|
|
libcrypto = find_library('libeay32')
|
|
else:
|
|
libcrypto = find_library('crypto')
|
|
|
|
if libcrypto is None:
|
|
return None
|
|
|
|
libcrypto = CDLL(libcrypto)
|
|
|
|
# typedef struct DES_ks
|
|
# {
|
|
# union
|
|
# {
|
|
# DES_cblock cblock;
|
|
# /* make sure things are correct size on machines with
|
|
# * 8 byte longs */
|
|
# DES_LONG deslong[2];
|
|
# } ks[16];
|
|
# } DES_key_schedule;
|
|
|
|
# just create a big enough place to hold everything
|
|
# it will have alignment of structure so we should be okay (16 byte aligned?)
|
|
class DES_KEY_SCHEDULE(Structure):
|
|
_fields_ = [('DES_cblock1', c_char * 16),
|
|
('DES_cblock2', c_char * 16),
|
|
('DES_cblock3', c_char * 16),
|
|
('DES_cblock4', c_char * 16),
|
|
('DES_cblock5', c_char * 16),
|
|
('DES_cblock6', c_char * 16),
|
|
('DES_cblock7', c_char * 16),
|
|
('DES_cblock8', c_char * 16),
|
|
('DES_cblock9', c_char * 16),
|
|
('DES_cblock10', c_char * 16),
|
|
('DES_cblock11', c_char * 16),
|
|
('DES_cblock12', c_char * 16),
|
|
('DES_cblock13', c_char * 16),
|
|
('DES_cblock14', c_char * 16),
|
|
('DES_cblock15', c_char * 16),
|
|
('DES_cblock16', c_char * 16)]
|
|
|
|
DES_KEY_SCHEDULE_p = POINTER(DES_KEY_SCHEDULE)
|
|
|
|
def F(restype, name, argtypes):
|
|
func = getattr(libcrypto, name)
|
|
func.restype = restype
|
|
func.argtypes = argtypes
|
|
return func
|
|
|
|
DES_set_key = F(None, 'DES_set_key',[c_char_p, DES_KEY_SCHEDULE_p])
|
|
DES_ecb_encrypt = F(None, 'DES_ecb_encrypt',[c_char_p, c_char_p, DES_KEY_SCHEDULE_p, c_int])
|
|
|
|
|
|
class DES(object):
|
|
def __init__(self, key):
|
|
if len(key) != 8 :
|
|
raise Exception('DES improper key used')
|
|
return
|
|
self.key = key
|
|
self.keyschedule = DES_KEY_SCHEDULE()
|
|
DES_set_key(self.key, self.keyschedule)
|
|
def desdecrypt(self, data):
|
|
ob = create_string_buffer(len(data))
|
|
DES_ecb_encrypt(data, ob, self.keyschedule, 0)
|
|
return ob.raw
|
|
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
|