README
1Crypt/OICQ version 1.0
2=====================
3
4 This module implements the cipher used by OICQ instant messaging protocol,
5used by Tencent Technology Limited, China.
6
7INSTALLATION
8
9To install this module type the following:
10
11 perl Makefile.PL
12 make test
13 su
14 make install
15
16DEPENDENCIES
17
18None
19
20ACKNOWLEDGEMENT
21
22FreeOICQ developers reverse-engineered Tencent's Win32 client binaries and
23published their discovery on http://sourceforge.net/projects/foicq/. Among
24their codes are segments of assembly code for the OICQ cipher and login key
25generation.
26
27I identified the algorithm for login key generation to be MD5.
28
29Chen Peng reverse-engineered the rest of assembly codes created by FreeOICQ and
30identified the core cipher used by OICQ to be a weakened version of TEA, Tiny
31Encryption Algorithm.
32
33TEA was invented by David Wheeler and Roger Needham at Cambridge University.
34They recommend using 32 rounds. OICQ only uses 16 rounds.
35
36COPYRIGHT AND LICENCE
37
38Copyright (c) 2003 Shufeng Tan. All rights reserved.
39
40This package is free software and is provided "as is" without express
41or implied warranty. It may be used, redistributed and/or modified
42under the terms of the Perl Artistic License (see
43http://www.perl.com/perl/misc/Artistic.html)
44
45