Watermarking computer program code

A method of detecting information embedded in a computer program code, the computer program code comprising a plurality of program statements and being adapted to cause, when executed by a data processing system, the data processing system to produce a program output, the method comprising:

• parsing the computer program code as to identify at least one conditional program statement, the conditional program statement including a condition and a plurality of alternative program statements, the conditional program statement being adapted to cause a data processing system to evaluate said condition and, responsive to a result of said evaluating step, to selectively execute one of said plurality of alternative program statements;
• wherein the plurality of alternative program statements are adapted to cause the computer program code to produce the same program output irrespective of which of said alternative program statements is executed;
• and
• extracting at least a part of said embedded information from the condition;
• wherein said information is encoded as one or more code words, each code word corresponding to one or more predetermined conditions.