IMPROVED DYNAMIC S-BOX ENCRYPTION FOLLOWED BY INTER PIXEL DISPLACEMENT FOR SECURE E-MAIL

Abstract: The security of the E-mail messages is an important issue; no such security is supported by the Internet standards. To overcome the attacks and to improve the security a new model is used which is "Secure Mail using Visual Cryptography". In this method the messages have to be transmitted is converted into a gray scale image. Then (2, 2) visual cryptographic shares are generated from the gray scale image. The shares are encrypted using A Chaos-Based Image Encryption Algorithm using Wavelet Transform and authenticated using Public Key based Image Authentication method. One of the shares is send to a server and the second share is send to the recipient's mail box. The two shares are transmitted through two different transmissions medium so man in the middle attack is not possible. If an adversary has only one out of the two shares, then he has absolutely no information about the message. At the receiver side the two shares are fetched, decrypted and stacked to generate the grey scale image. From the grey scale image the message is reconstructed .But in this can see an outline of image from one share. And also Encryption techniques used for encrypting textual data does not work with images, so separate encryption techniques are required for images. So, we proposed here a new scheme for image encryption which is helpful for end to end secure transmission of digital information on open network using explosive block displacement followed by inter-pixel.

Keywords: chaos based image encryption algorithm, low frequency wavelet coefficient, visual cryptography, dynamic s-box algorithm, wavelet decomposition, Image Encryption, Block, Transformation, Inter-Pixel.