For blind extraction, there are some necessary parameters need to be recorded as auxiliary information. For example, for a 512 × 512 sized gray-scale image, the auxiliary information includes• the parameters b (2 bits), T (10 bits), and m (3 bits),• the optimal expansion path P7,m (m + 7 bits),• the length of compressed location map (18 bits),• the compressed location map,• the end position which is the last modified pixel pair (16 bits).