High-Capacity Reversible Data-Hiding for LZW Codes

Compression and data-hiding can reduce transmission cost and secure transmissions, respectively, but hiding information directly in the compression codes is one way to meet the two requirements simultaneously. Because of the low redundancy, few lossless compression methods have been applied in the research. Lempel-Ziv-Welch (LZW) coding is a well-known lossless compression algorithm that is simple and does not require prior analysis of the source or send extra information to the decoder. In this paper, we propose a high-capacity data-hiding LZW (HCDH-LZW) method that hides data in LZW compression codes reversibly by shrinking the symbol length. The hiding scheme increases capacity for the number of symbols available to hide secrets but also the capacity of each symbol. Experimental results demonstrate the high embedding capacity of the proposed method.