It includes Digital Watermarking as well as Text Digital Watermarking and have an Process of embedding a digital watermark into a digital text document. It is mainly proposed in 1995 by Brassil and Low. The Classification is based on the format as well as based on expand space along with the based on semantics. Also there is a format based Text watermarking.
There are three methods of doing this process which are line shift coding, word shift coding and feature coding. Watermark capacity and robustness of most algorithms in this technique are unsatisfactory. There is a need to Enhancing robustness using Fragments regrouping strategy.
The Merits and demerits if the same includes: Line shift coding has stronger robust but low watermarking capacity. Word shift coding has better watermarking imperceptibility. Feature coding is hard to implement for all kind of formats.
How to do it? Take a Malayalam text document and watermark. Fragment the watermark. Take the characters with the loops in the text document and embed the fragments with the hash functions into the documents redundantly. Wait for the output.