Word length based zero-watermarking algorithm for tamper detection in text documents

Copyright protection and authentication of digital content has become a major concern in the current digital era. Plain text is the widely used means of information exchange on the Internet and it is essential to verify the authenticity of information in any form of communication. There are very limited techniques available for plain text watermarking, authentication, and tamper detection. This paper presents a novel zero-watermarking algorithm for tamper detection in plain text documents. The algorithm generates a watermark based on the text contents which can be extracted later using extraction algorithm to identify the status of tampering in the text document. Experimental results demonstrate the effectiveness of the algorithm against random tampering attacks. Watermark pattern matching and watermark distortion rate are used as evaluation parameters on multiple text samples of varying length.