Stigmata is rewrite almost every source code based on jbirth which available at http://se.naist.jp/jbirth. Stigmata aims to detect the theft of programs, too. This tool can extract birthmarks from Java class files, and compare them. Differences from jbirth are

  • using spi (service provider interface) architecture for birthmark implementation
  • using ASM instead of BCEL.
  • introducing birthmarking context
  • implementing new birthmarks (k-gram, frequency of used classes, frequency of method calls)
  • new analysis method for extracted birthmarks
  • show extracted birthmark histories.

A software birthmark is a set of special informations that the program originally possesses. The software birthmark is carefully extracted from critical portions of class file. Hence, if a class file p has the same software birthmark as another class file q's, q is very likely to be a copy of p. Thus, the software birthmark can be used as a simple but powerful signature to distinguish doubtful class files (those which seem to be copies).


Stigmata support the extracting birthmarks from Java class files, and written in Java 5 with ASM.

The main features are:

  • extraction of the four types of birthmarks directly from Java class files (without source code),
  • pairwise birthmark comparison of Java class files,
  • Jar file and War file support,
  • plug-in architecture for new birthmarks,
  • analysis of extracted birthmarks (MDS), and
  • show back extracted birthmark histories


Contact us by emal <tama3[ at ]users.sourceforge.jp>