Japanese Page


KDDI R&I Laboratories Inc.
Address: 2-1-15 Ohara, Kamifukuoka, Saitama, 356-8502 Japan
TEL: +81-49-278-7575
E-mail: ka-fukushima(atmark)kddilabs.jp


Belong to: KDDI R&D Laboratories Inc.


Java Obfuscation


Recently, the situation of circulation of software is changing a lot, with spread of computer networks including the Internet. Although almost all software has been distributed in binary form, the case where the software in the source code form of Java or C is distributed is increasing. In this situation, a malicious third person can analyze the software. As a result, secret data may be stolen and the intellectual property rights of algorithms may be infringed. Obfuscation is one of the techniques to solve this problem. Obfuscation makes the program more difficult for a reverse-engineer to understand but do not affect the functionality of the program. In our research, we separate fields and methods in order to destroy these encapsulated structures. By this mean we successfully obfuscate the source code of Java. Moreover by applying another obfuscation technique of Sakabe et al. using interfaces and method-overloading in pile, we can make point-to analysis of the program NP-hard. As a result, we can give the theoretical basis of security to static analysis.


Kazuhide FUKUSHIMA, Kouichi SAKURAI:
``A proposal of an obfuscation technique by distributing methods",
Computer Security Symposium 2002 (CSS2002), pp.191-196, Oct, 2002

Java Fingerprinting


It is effective that embedding the personal identifier as watermarking to a program to prevent theft of Java classfiles. Monden et al. proposed watermarking scheme for embedding arbiter character sequence to target Java classfiles. But the scheme can be used to embed only the same watermarking to all the programs. For this reason, if we apply the scheme to embed personal identifier, the watermark can be specified by comparing two or more users' program.In this paper, we solve the problem by using the obfuscation scheme. Moreover we try to raise the security of classfiles.


Kazuhide FUKUSHIMA, Kouichi SAKURAI:
``Obfuscating of Embedding Position of the Software Fingerprinting",
Symposium on Cryptography and Information Security (SCIS2003) , pp.1053-1058, Jan, 2003

Valid HTML 4.01!