Fragile blockwise image authentication thwarting vector quantization attack

In this paper, the development of effective blockwise image authentication techniques, thwarting vector quantization attacks, is addressed. We present a critical attack localization uncertainty problem with the recent hierarchical watermarking algorithm. Addressing it and shortcomings of other existing techniques, we propose the use of a randomly-variable block size and a chain with multiple links for embedding several signature copies per block in arbitrarily distant blocks. These proposed schemes devise a novel fragile blockwise image authentication algorithm with improved security and attack localization.