A Novel Modulo (2n + 1) Multiplication Approach for IDEA Cipher

This paper covers the FPGA implementation of the International Data Encryption Algorithm (IDEA) using Very Large Scale Integrated Circuits Hardware Description Language (VHDL) with device as Vertex II Pro XC2VP30 using Xilinx – ISE 10.1. IDEA is very much fast and entirely based on internal group operations-XOR, modulo addition and modulo multiplication. So unlike other symmetric key block ciphers like AES or DES, there is no need for S-Boxes or P-Boxes in round operations. To use an encryption algorithm in real time applications like Cable TV, Video conferencing, the speed i.e. the data throughput rate needs to be high. The multiplication modulo (2n + 1) is the main module of this IDEA block cipher, as this module is highly computation intensive and consumes a lot of time. Due to regularity of IDEA, it has been implemented in hardware several times using different architectures. This paper mainly focuses on implementing a new algorithm and architecture for modulo (2n + 1) multiplication which takes the input in a diminished-1 form [2] and produces the product in the same form. This is a new modulo (2n + 1) approach for implementing IDEA in hardware. The proposed multiplier optimizes the time by producing n/2 partial products and handles zero values very efficiently. The performance of the proposed multiplier is analyzed in terms of time delay and circuit complexity and is compared with some existing schemes of diminished-1 modulo multipliers like Zimmerman [15], Sousa and Chaves [10] and Efstathiou [15][ 3].