tools v2.2

eReader_PDB_Tools/lib/openssl_des.py

@@ -0,0 +1,90 @@
+#!/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 Error('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
+