Designing of High-Speed Image Cryptosystem Using VQ Generated Codebook and Index Table

Internet now a day, is one of the most popular mode of communications, and its popularity suffers from a vital issue of not supporting the security of the confidential data during transmission. In this work, a high-speed cryptosystem for image data has been developed for efficient and secured communication over Internet. The basic idea is that the given image is first compressed by VQ for traffic reduction, then instead of using conventional techniques like DES, RSA, and so on for encryption and decryption, the codebook or index-table are encrypted by the proposed technique which is basically the combination of a simple XOR operation followed by certain random shuffling techniques. The security of the proposed cryptosystem depends on the generation and the exchange of the random sequences used and if it could be done truly, which is not possible practically, the proposed scheme would be a perfect cryptosystem. However, if any publicly known technique is considered to generate the pseudorandom numbers and used, where for security the seed is kept secret and exchanged using the techniques used in symmetric-key cryptography for exchange of symmetric-key, it serves the propose. From the simulation results it has been found that the proposed cryptosystem provides the expected performance.