[1] G J Simmons.A secure subliminal channel.In :Advances in Cryptology-Crypto ′85, Lecture Notes in Computer Science, Vol.963.Springer-Verlag,1985.33-41

[2] G J Simmons.The subliminal channel in the U.S.Digital Signature Algorithm (DSA).In:Proceedings of 3rd Symposium on State and Progress of Researchin Cryptography-SPRC ′93.Norway :Lofthus, 1993.35-54

[3] L Harn, G Gong.Digital signature with a subliminal channel.IEE Proc.Comput.Digit.Tech., 1997,144(6):387-389

[4] J K Jan, Y M.New digital signature with subliminal channels based on the di screte logarithm problem.In :Proc.1999 International Workshop on Parallel Processing.1999.198-203