Data hiding using VQ index file

This paper modifies an elegant data hiding method of Chang et al's [Pattern Recog. Lett. 2004, vol. 25, no. 11, 1253-1261]. The embedding employs a modified search-order coding (SOC) technique to hide binary secret data in the vector quantization (VQ) index file of a host image. The recovered host image is identical to the one recovered by traditional VQ; the compression rate is competitive to traditional VQ's (often better than traditional VQ's if we use t = 1 mode); while the hidden binary data is revealed in the decompression procedure as a bonus. The compression rate and hiding capacity are also better than those in Chang et al's.