%0 Journal Article %T A Very Compact AES-SPIHT Selective Encryption Computer Architecture Design with Improved S-Box %A Jia Hao Kong %A Li-Minn Ang %A Kah Phooi Seng %J Journal of Engineering %D 2013 %I Hindawi Publishing Corporation %R 10.1155/2013/785126 %X The ¡°S-box¡± algorithm is a key component in the Advanced Encryption Standard (AES) due to its nonlinear property. Various implementation approaches have been researched and discussed meeting stringent application goals (such as low power, high throughput, low area), but the ultimate goal for many researchers is to find a compact and small hardware footprint for the S-box circuit. In this paper, we present our version of minimized S-box with two separate proposals and improvements in the overall gate count. The compact S-box is adopted with a compact and optimum processor architecture specifically tailored for the AES, namely, the compact instruction set architecture (CISA). To further justify and strengthen the purpose of the compact crypto-processor¡¯s application, we have also presented a selective encryption architecture (SEA) which incorporates the CISA as a part of the encryption core, accompanied by the set partitioning in hierarchical trees (SPIHT) algorithm as a complete selective encryption system. 1. Introduction In the year 1972, the National Institute of Standards and Technology (NIST) has identified and further concluded the study of the US government¡¯s computer security needs its own standard for encrypting government-class sensitive information. After various proposal submissions which did not meet their vigorous design requirements, a cipher candidate developed in IBM was deemed suitable and the NSA worked closely with IBM to strengthen that algorithm. Eventually, the Data Encryption Standard (DES) was approved as a federal standard in November 1976. From there onwards, the pillar and model of the encryption for data are formed and established as DES having influenced the advancements of the modern cryptography for many years on. Since cryptographic solutions are often used to offer integrity and security over the transmission of sensitive data in our communication mediums, it is important for them to have consistent and nondecaying cryptographic strength over time. However, the strength of the encryption is weighted on the key itself, resulting in the strength being exploitable given massive computation strength to search for the key within a finite key space. Over time, the advances of computing technology have dramatically improved the computer processing power and have rendered the earlier DES with the small-sized 56-bit key as no longer safe. This is because of the far more superior computing power we have today, compared to those computers in the earlier days when the DES is proposed. This was quickly rectified later by replacing %U http://www.hindawi.com/journals/je/2013/785126/