Error correcting codes and their usage in steganography and watermarking

Steganography and Digital Watermarking are concerned with embedding information in digital media such as images, audio signals and video. Both scientific disciplines develop methods for conceal message (a sequence of bits) by modifying the host (cover) digital object but their goals are slightly different. In this work we discuss two methods of information embedding in spatial domain: a matrix embedding by q-ary codes and a method based on pseudo-noise patterns and which explodes the erasure capability of error correcting codes. We have made numerous experiments with picture from several galleries (with grey-scale and color images) and many error control codes for both type of algorithms. Our observations show that q-ary codes are good choice in the case of syndrome embedding.