Fast encryption methods for audiovisual data confidentiality
Chung-Ping Wu, C.‐C. Jay Kuo · Proceedings of SPIE, the International Society for Optical Engineering/Proceedings of SPIE · 2001
Two methodologies for efficient audiovisual data encryption are studied in this research, i.e. selective encryption and MHT (multiple-Huffman-table). We first discuss benefits and limitations of selective encryption, and propose a selective encryption scheme for ITU G.723.1 speech coding. A review of all cryptanalysis work of selective encryption algorithms in the literature is given, our cryptanalysis for the JPEG/MPEG sign-bit encryption scheme is presented, and two rules to determine whether selective encryption for a compression system is suitable are concluded. Then, we investigate another encryption methodology via the manipulation of Huffman coding tables of multimedia coding systems. The MHT scheme chooses several different Huffman tables from a vast number of possible candidates, and uses them alternatively to encode multimedia data. The choice of Huffman tables and the order that they are used are kept secret as the key. This method requires very little computational overhead, and can be applied to the encryption of MPEG audio, MPEG video and JPEG/JPEG2000 images.