Modified RSA public key algorithm

Modern cryptography is heavily based on mathematical theory and computer science practice, cryptographic algorithms are designed around computational hardness assumptions. Among the various techniques adopted in cryptographic technology the RSA (Rivest, Shamir and Adleman) is the most widely used public key cryptosystem. The basic operation for this algorithm is modular exponentiation. Modular multiplication is the core computation of all modular exponentiation algorithms, Montgomery´s method is considered as the most efficient algorithm for performing the modular multiplication operation. This paper presents two architectures for FPGA implementation of modular exponentiation algorithm based on Montgomery technique - one with parallel technique and another with maximum sequential operation. Finally these architectures are analyzed with respect to area, speed, and power using Xilinx ISE.