Abstract: Steganography is the art and science of communicating in such a way that the presence of a message cannot be detected. Itincludes the concealment of information within computer files. This paper considers an information theoretic model for steganography with a passive adversary being proposed. This paper considers an information theoretic model for steganography with a prime number insertion with being proposed. The adversary’s task of distinguishing between an innocent cover message C and modified message S containing hidden information is interpreted as a testing problem. Depending on this evenness, the character is encrypted differently. This paper describes how image degradation improve with this technique as well enhance security with proposed prime technique.

Keywords: Cryptography, Least Significant Bit (LSB), Prime Sequence Generator , Steganography.