On the Security of Multimedia Encryption Schemes Based on Multiple Huffman Table (MHT)

This paper addresses the security issues of the multimedia encryption schemes based on multiple Huffman table (MHT). A detailed analysis of known-plaintext attack is presented to show that the Huffman tables used for encryption should be carefully selected to avoid the weak keys problem. Further, we propose an efficient chosen-plaintext attack on the basic MHT method as well as the enhanced scheme inserting random bits. We also show that random rotation in partitioned bit stream cannot essentially improve the security.