A visual information encryption algorithm for video conference

For a typical video conference system, generally it is required to satisfy some basic requirements such as real-time and security. In the past few years, a large number of investigators concentrate on how to develop efficient video encryption algorithms, which are mainly fell into three categories: complete encryption, selective encryption, and entropy coding based encryption. Among above three kinds of algorithms, they all remain some shortcomings. For example, complete encryption is safe but computation expensive, selective encryption usually can destroy the statistical characteristic of DCT coefficients and then results in compression-efficiency reduction, and entropy coding based encryption suffers from the issue that some encrypted results of codewords indices are possibly no corresponding codewords since the codeword index set of coding table is just a subset of all possible results of encrypted index. This paper presents a lightweight complete encryption algorithm based on efficient XOR operation and hierarchical encryption strategy, successfully overcoming the weakness of complete encryption while offering a better security.