Employee information hiding image technic using cryptographic
Abstract : Steganalysis is the art of detecting the message's existence and blockading the covert communication. Various steganography techniques have been proposed in literature. The Least Significant Bit (LSB) steganography is one such technique in which least significant bit of the image is replaced with data bit. As this method is vulnerable to steganalysis so as to make it more secure we encrypt the raw data before embedding it in the image. Though the encryption process increases the time complexity, but at the same time provides higher security also. This paper uses two popular techniques Rivest, Shamir, Adleman (RSA) algorithm and Diffie Hellman algorithm to encrypt the data. The result shows that the use of encryption in Steganalysis does not affect the time complexity if Diffie Hellman algorithm is used in stead of RSA algorithm.
? Cryptography prevents unauthorized party from discovering the content of communication but Steganography prevents discovery of the existence of communication (i.e., Cryptography makes data gibberish and known the message passing while Steganography tends to conceal presence of hidden data and unknown the message passing).
? The PSNR and Maximum Hidden Capacity (MHC) of this technique are high comparing to the existed techniques.
? More information than that other existed methods and the visual quality of the stego image is also improved, in addition to it is effective for secret data communication.
? Cryptography problem is that, the cipher text looks meaningless, so the attacker will interrupt the transmission or make more careful checks on the data from the sender to the receiver.
? Steganography problem is that once the presence of hidden information is revealed or even suspected, the message is become known.
? The main issue is that the secret message will not be unnoticed if a third party tries to intercept the cover media (cover image).
? Although cryptography and steganography could be used to provide data security, each of them has a problem.
• The main objective of the proposed method is to introduce more secure communication by merging cryptography and steganography techniques to make it more difficult for a steganalyst to retrieve the plaintext of a secret message from a stego-object.
• The idea of this proposed algorithm is that using the digits of MPK encoding instead of bits of secret message in hidden step to increase the capacity and quality because MPK encoding represents each character by two digits instead of 8 bits.
• In, a new method has been proposed for hiding any encrypted secret message inside a cover file.
• The performance of the proposed merged algorithm is evaluated by measuring imperceptibility (Stego-image quality), and payload (hiding capacity).
? The number of instructions executed is a measure of time complexity of the algorithm therefore we calculated the number of instructions executed both at sender and receiver side to compare the performance of pure steganography and our proposed scheme.
? To check the efficacy of the proposal, we calculated the number of instructions executed at sender and receiver site since the number of instructions executed is a measure of time complexity of the process.
? The image is now used as a cover to embed the encrypted information.
? This process is done by LSB encoder which replaces the least significant bit of pixel values with the encrypted information bits.
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