Accelerating the Secure Remote Password Protocol Using Reconfigurable Hardware

Abstract

The Secure Remote Password (SRP) protocol is an authentication and key-exchange protocol suitable for secure password verification and session key generation over insecure communication channels. The modular exponentiations involved, however, are very time-consuming, causing slow logon procedures. This work presents the design of a hardware accelerator that performs modular exponentiation of very wide integers. The experimental platform is tutwlan, a Wireless Local Area Network (wlan) being developed at Tampere University of Technology. It runs on the Altera Excalibur development board that contains a microprocessor and a chip with programmable hardware. The results show that a full modular exponentiation with 1023-bit inputs can be performed in less than 40 ms using less than 10,000 logic elements, each consisting of a 4-input lookup table and a register. By using the implemented hardware accelerator in the authentication protocol, the execution time is reduced by a factor of 4. In addition, proposals to improve the implemented modular exponentiation architecture are presented. An additional factor of 5 improvement (totaling a factor of 20) can be achieved by implementing the fastest design