Life Science Journal 2013;10(3) http://www.lifesciencesite.com 1107 Area efficient cryptographic ciphers for resource constrained devices T. Blesslin Sheeba 1 , Dr. P. Rangarajan 2 1. Department of ECE, Sathyabama University, Chennai-600087, India 2. Department of EEE, RMD Engineering College, Chennai-600087, India blesslinsheebarmk@gmail.com Abstract: The upcoming area of pervasive computing will be characterized by many smart devices that have very limited resources in terms of memory, computing power and battery supply. In information technology, Ubiquitous which is widely believed to be the next paradigm .The mass deployment of pervasive devices promises on the one hand many benefits, but on the other hand, many foreseen applications are security sensitive. In order to provide security on resource constrained devices lightweight cryptographic algorithms have been developed. In this paper we propose lightweight cryptography for FPGAs by introducing block cipher independent optimization techniques for Altera Cyclone III FPGAs and applying them to the lightweight cryptographic algorithms HIGHT and Present. Both are less than half the size of the AES implementation without using block RAMs. [T. Blesslin Sheeba, P. Rangarajan. Area efficient cryptographic ciphers for resource constrained devices. Life Sci J 2013;10(3):1107-1114] (ISSN: 1097-8135). http://www.lifesciencesite.com . 161 Keywords: AES, Block cipher, Camellia, FPGAs, Lightweight cryptography. 1. Introduction Ubiquitous computing represents the third area of computing devices after mainframes and personal computer for first and second eras. Radio frequency identification (RFID) tags and wireless sensor network (WSN) nodes are a few examples which are being used for automated electronic toll systems, identification tags for food products, pets, clothing and so on. This brings us close to the threshold of pervasive computing. The mass deployment of this device brings serious concerns for security and privacy[18]&[19]. The traditional cryptographic algorithms may not be suitable for these devices as they have limited memory and computational power along with serious power constraints. This led to development of new branch of cryptography called lightweight cryptography. HIGHT and Present were developed specifically for lightweight cryptography AES and Camellia, though not considered lightweight, and are also being used on these devices. Until now, lightweight cryptography is targeted towards application specific integrated circuits (ASICs). ASICs involve high non-recurring engineering cost and long time to market where as Field Programmable Gate Arrays (FPGAs) involve low non-recurring engineering cost and less time to market. The dominant factor favorable to ASICs is their lower power consumption, which is of primary concern for lightweight cryptographic devices and their lower cost in large volumes. With the advent of low-cost and low-power FPGAs, we expect them to become popular for battery powered applications such as WSN nodes. Hence, they are a targeted for lightweight cryptographic applications. Reconfigurability of FPGAs allows the system to be upgraded if ever the need arises which is not possible with ASICs. Furthermore, lightweight crypto implementations lead to area saving over traditional implementations. This enables a designer to add crypto to an existing design at a minimal cost or to reduce the overall area consumption which might lead to cost saving as the design might now fit into a smaller, cheaper FPGAs. The ciphers considered are of full strength security i.e. 128-bit key length, even though traditional lightweight cryptography considers 80-bit key length to be sufficiently secure. 2. Materials and Methods Advanced Encryption Standard The Advanced Encryption Standard (AES) specifies FIPS-approved cryptographic algorithm that can be used to protect electronic data. The algorithm AES is a symmetric block cipher that can encrypt (encipher) and decrypt (decipher) information. In cipher text encryption converts data to an un- intelligible form, decrypting the cipher text converts orginal form of data called plaintext. A cryptographic key of 128, 192, and 256 bits to encrypt and decrypt data in blocks of 128 bits is possible in AES algorithm. The specified standard algorithm may be implemented in software, firmware or hardware. The specific implementation may depend on several factors such as the application, the environment and technology.