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xxtea.py
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xxtea.py
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############################################################
# #
# The implementation of PHPRPC Protocol 3.0 #
# #
# xxtea.py #
# #
# Release 3.0.0 #
# Copyright (c) 2005-2008 by Team-PHPRPC #
# #
# WebSite: http://www.phprpc.org/ #
# http://www.phprpc.net/ #
# http://www.phprpc.com/ #
# http://sourceforge.net/projects/php-rpc/ #
# #
# Authors: Ma Bingyao <andot@ujn.edu.cn> #
# #
# This file may be distributed and/or modified under the #
# terms of the GNU Lesser General Public License (LGPL) #
# version 3.0 as published by the Free Software Foundation #
# and appearing in the included file LICENSE. #
# #
############################################################
#
# XXTEA encryption arithmetic library.
#
# Copyright (C) 2005-2008 Ma Bingyao <andot@ujn.edu.cn>
# Version: 1.0
# LastModified: Oct 5, 2008
# This library is free. You can redistribute it and/or modify it.
import struct
_DELTA = 0x9E3779B9
def _long2str(v, w):
n = (len(v) - 1) << 2
if w:
m = v[-1]
if (m < n - 3) or (m > n): return ''
n = m
s = struct.pack('<%iL' % len(v), *v)
return s[0:n] if w else s
def _str2long(s, w):
n = len(s)
m = (4 - (n & 3) & 3) + n
s = s.ljust(m, "\0")
v = list(struct.unpack('<%iL' % (m >> 2), s))
if w: v.append(n)
return v
def encrypt(str, key):
if str == '': return str
v = _str2long(str, True)
k = _str2long(key.ljust(16, "\0"), False)
n = len(v) - 1
z = v[n]
y = v[0]
sum = 0
q = 6 + 52 // (n + 1)
while q > 0:
sum = (sum + _DELTA) & 0xffffffff
e = sum >> 2 & 3
for p in xrange(n):
y = v[p + 1]
v[p] = (v[p] + ((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z))) & 0xffffffff
z = v[p]
y = v[0]
v[n] = (v[n] + ((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[n & 3 ^ e] ^ z))) & 0xffffffff
z = v[n]
q -= 1
return _long2str(v, False)
def decrypt(str, key):
if str == '': return str
v = _str2long(str, False)
k = _str2long(key.ljust(16, "\0"), False)
n = len(v) - 1
z = v[n]
y = v[0]
q = 6 + 52 // (n + 1)
sum = (q * _DELTA) & 0xffffffff
while (sum != 0):
e = sum >> 2 & 3
for p in xrange(n, 0, -1):
z = v[p - 1]
v[p] = (v[p] - ((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[p & 3 ^ e] ^ z))) & 0xffffffff
y = v[p]
z = v[n]
v[0] = (v[0] - ((z >> 5 ^ y << 2) + (y >> 3 ^ z << 4) ^ (sum ^ y) + (k[0 & 3 ^ e] ^ z))) & 0xffffffff
y = v[0]
sum = (sum - _DELTA) & 0xffffffff
return _long2str(v, True)
def decrypt_file(src_file, key, target_file=None, sign=""):
with open(src_file, "rb") as file_obj:
cipher_text = file_obj.read()
plain_text = cipher_text
sign_text = cipher_text[0:len(sign)]
if sign_text == sign:
cipher_text = cipher_text[len(sign):]
plain_text = decrypt(cipher_text, key)
if len(plain_text) == 0 and len(cipher_text) > 0:
return False
if target_file:
with open(target_file, "w") as write_obj:
write_obj.write(plain_text.replace("\r\n","\n"))
write_obj.close()
return True
return False
if __name__ == "__main__":
print decrypt(encrypt('Hello XXTEA!', '16bytelongstring'), '16bytelongstring')