DWT-AES Processor for a Reconfigurable Secure Image Coding

Abstract

In this paper, we proposed a reconfigurable secure image codec based on the Discrete Wavelet Transformation (DWT) and the Advanced Encryption Standard (AES) processor. Either, use of image coding with DWT or encryption using AES is well known. However, linking these two designs to achieve secure image coding is leading. The prominent feature of this method is a partial encryption of bass frequency (LL bands) by AES-128 (128-bit keys), or AES-192 or AES-256. Our approach provides considerable levels of security (key size, partial encryption, encryption mode), and has very limited adverse impact on the compression efficiency. The proposed codec can provide up to 9 cipher schemes within a reasonable software cost. Correlation, PSNR and compression rate results from these codec are analyzed Our codec present the bloc DWT of JPEG2000 and the bloc Huffman coding of JPEG. So, the sensibility of the Human Visual System (HVS) to DCT based image processing cause a lot error (4). From this point of view the discrete wavelet transform (DWT) is a very attractive version of the frequency models for the HVS. The Huffman coding presents an advantage to be less complex and few calculations than EBCOT. The JPEG and JPEG2000 codec are presented and compared in (4). Furthermore, we combine the compression and encryption into single process upon user need. We improved an approach called band LL encryption to reduce encryption and decryption time in image communication and processing. The encryption-decryption effects are achieved by the AES algorithm (5). In our approach, AES is aim to encrypt group of LL bands. The prominent feature of this method is an encryption of LL bands by AES-128 (128-bit keys), or AES-192 (192-bit keys), or AES-256 (256-bit keys). Instead, we focus on a method that implements partial encryption of LL bands. Our codec can provide up to 9 cipher band LL encryption schemes. Using a security vector, the user can allot a precise security service of his application (security or no, encryption or decryption, key-length, full encryption or LLi band encryption, ECB or CBC mode). Our unified software design can run both our proposed image codec and the extended