Design of Image Cryptosystem by Simultaneous VQ-Compression and Shuffling of Codebook and Index Matrix

TL;DR

This paper proposes a fast image encryption scheme using vector quantization that simultaneously compresses and encrypts images by shuffling codebooks and index matrices with pseudorandom sequences, enhancing security without traditional cryptography.

Contribution

It introduces a novel VQ-based image cryptosystem that combines compression and encryption through codebook and index matrix shuffling using pseudorandom sequences, reducing processing time.

Findings

The scheme effectively encrypts images while compressing them.

It has lower processing time compared to traditional cryptosystems.

Simulation results demonstrate the scheme's expected performance.

Abstract

The popularity of Internet usage although increases exponentially, it is incapable of providing the security for exchange of confidential data between the users. As a result, several cryptosystems for encryption of data and images have been developed for secured transmission over Internet. In this work, a scheme for Image encryption/decryption based on Vector Quantization (VQ) has been proposed that concurrently encodes the images for compression and shuffles the codebook and the index matrix using pseudorandom sequences for encryption. The processing time of the proposed scheme is much less than the other cryptosystems, because it does not use any traditional cryptographic operations, and instead it performs swapping between the contents of the codebook with respect to a random sequence, which resulted an indirect shuffling of the contents of the index matrix. It may be noted that the security of the proposed cryptosystem depends on the generation and the exchange of the random sequences used. Since the generation of truly random sequences are not practically feasible, we simulate the proposed scheme using MATLAB, where its operators like rand(method, seed), randperm(n) has been used to generate pseudorandom sequences and it has been seen that the proposed cryptosystem shows the expected performance.