Research on watermark of electronic examination paper

Electronic examination paper (EEP) should be protected in copyright and tamper-resistant in its lifetime. A security solution based on watermark for this problem is given in this paper. Two kinds of watermark are designed: copyright watermark and tamper-resistant watermark. Copyright watermark is an ID of the examination, which is consists of proposition, time of exam, exam taker, object of examination, etc.. Tamper-resistant watermark is produced in two methods. One is constructed by embedding the abstract information into the paper by changing the title line format. Another is based in attribution of the paper such as words, characters, paragraphs, etc.. Simulated attacks detections show that the copyright watermark is robust and tamper-resistant watermark can detect the modification on examination paper caused by active attacks.