A Method for Public Key Method of Steganography

ABSTRACT Security of the digital information is becoming primary concern prior to transmitting the information itself via some media. Information security means protecting information and information systems from unauthorized access, use, disclosure, disruption, modification or destruction. In this paper, a public key method of Steganography is proposed under standard cryptographic assumptions. The byte location in LSB of which the secret bit is to be embedded is found out by public key of the receiver and receiver apply private key of itself to reconstruct the secret message following RSA assumptions. General Terms time of hiding based on a particular public key Steganography, Security. Keywords Communication, Security, Steganography 1. INTRODUCTION Steganography is a technology that hides a message within an object, a text, or a picture. It is often confused with cryptography, not in name but in appearance and usage. The easiest way to differentiate the two is to remember steganography conceals not only the contents of the message but also the mere existence of a message. The original steganographic applications used “null ciphers” or clear text. A null cipher conveys that the message has not been encrypted in any way, whether it is using basic character shifting, substitution or advanced modern day encryption algorithm. So, the message is often in plain view but for a reason can either not be detected as being present or cannot be seen once detected. As is common with cryptography, steganography has its roots in military and government applications and has advanced in ingenuity and complexity. Steganography is the science of hiding secret information by means of some carrier file [1]. The secret information in general is embedded into some media file like image or audio and thus it is transmitted so as to prevent an opponent from guessing that some secret information is being transmitted. So, the main objective of Steganography is not to let the opponent guess that any kind of information apart from the media file itself is transmitted. In spatial domain of Steganography by using Image as the carrier file, we, in general, invert the Least Significant Bit of a particular byte of the carrier image to embed a particular bit of Secret message [2,3,4]. This method is known as LSB (Least Significant Bit) masking method of Steganography. In this paper, a public key method of Steganography is proposed under RSA cryptographic assumptions. In the proposed algorithm, RSA is used not to encrypt the secret message but to find the exact Byte location of the carrier file, in LSB of which a particular bit of the secret message is to be embedded. For a particular bit of the message file, we employ RSA encryption algorithm to generate a cipher. The LSB of the Red or Green or Blue value of a particular pixel represented by the cipher is then inverted only if the particular bit of the secret message is one. Likewise, we can embed the entire secret message into the carrier file and thereby we can send the embedded file called stego image and the carrier file to intended recipient. Upon receiving, recipient can apply XOR operation on the carrier image and the stego image to find the inverted LSBs. Then applying RSA Decryption algorithm on the location of a particular inverted LSB, we get the original position of the bit in the message file and thus can reconstruct the message file. Thus, this algorithm scatters the information at the -private key combination.