Abstract: The advantages and disadvantages of the four existing text watermarking algorithms arc presented. ho en- hance the security and robustness of the watermarking information, the RSA encryption algorithm and 13CH error cor- rection of coding are used. The watermarking is embed by changing the RGI3 component of the document characters. U- sing the random to choose the embed position has improved security of the algorithm. The test shows that the algorithm has high watermarking capacity and great watermarking imperceptibility. The applied situation of the algorithm is intro- duced in the end.

Key words: Next watermarking, Encrypt, Error correcting coding, RGI3 component