Study On Subliminal Channel Base Of ElGamal Digital Signature Scheme

The subliminal channel is used as an important realization of Information-hiding technology and it has drawn more and more attention, The research of subliminal channel includes two aspects: one aspect is to structure subliminal channel for the safety information transmission service for the network user; Another aspect is to close the subliminal channel in order to prevent the network attacker who engaged in illegal activities.The thesis has introduced subliminal channel's origination, development and application. Analyzing the technology of digital signature, and expositing the conception, basic model and causes.The thesis has studied the scheme of ElGamal subliminal channel, has analyzed the deficiency of ElGamal subliminal channel, and accordingly brought forward the improved scheme. The improved scheme succeed in preventing warden's detection of subliminal channel and improves the application security of subliminal channel by using of one-time pad algorithm's encryption of Subliminal information. Meanwhile, the artificial system of prototype which improves the scheme based on VC ++ 6.0 development environment has proved to the improved scheme.The thesis has studied the theory and the scheme of closed subliminal channel. It has given a detailed analysis of scheme about closed subliminal channel which is brought forwards by Simmons in 1998. It also analyzes the defect of cuckoo's channel's existence, and has offered the improved closed scheme. The improved scheme succeeds in closing the cuckoo's channel which exists in the scheme of Simmons.