German researchers develop ‘Birthmark’ for piracy check

Researchers at Saarland University in Germany have developed a method that detects similarities between programs that can be used for identifying software piracy.

Called API Birthmark, the tool can scan a program and look for similarities it has with another piece of software based on its behaviour, according to Valentin Dallmeier, one of three researchers at the university’s Software Engineering Chair who developed this software analysis tool. What’s noteworthy about this approach, said Dallmeier, is that it compares and looks for similarities in the behaviour of the programs, rather than in the actual code.

Developers who illegally use code from a licensed program typically employ obfuscation techniques in an effort to evade detection by code-based scanning tools. Obfuscating the code does not necessarily change the functionality of the program, said Dallmeier.

“These obfuscation techniques only change the code in the program, but they cannot alter the behaviour without destroying the program and (losing) its functionality,” the researcher explained.

API Birthmark analyzes the behaviours of a particular program and compares them with other programs. The higher the degree of similarity between two different pieces of software the greater the likelihood of code theft is.

Dallmeier said API Birthmark looks at the interaction between a program and the operating system or the application programming interface (API), depending on the language the program was written. It then captures that interaction and compares it with other programs, he said.

The API Birthmark can be valuable to big software developers for conducting competitive analysis, said Michelle Warren, Toronto-based senior research analyst at Info-Tech Research Group.

API Birthmark can be used to evaluate other software products for possible copyright violations. It can also be used as an analysis tool in their own software development labs to ensure that their codes are not infringing on any copyrights, Warren explained.

The tool’s behaviour-based scanning method also makes it more effective than the traditional code-based analysis tools, she said.

“It’s like writing an essay,” said Warren. “Sentences can be created just coincidentally using the same words (as another piece of essay), but if we look at the actual idea and the thought patterns and the beliefs, that is really at the core of any kind of (intellectual property) theft.”