30 DESIGNSPACEEXPLORATIONOFA RECONFIGURABLE HMAC-HASH UNIT
Fayez Gebali · 2006
In thispaper,a designspaceexploration of a reconfigurable HMIAC-hash unitisdiscussed. Thisunit implements oneofsixstandard hashalgorithms, namely, MD5,SHA-1, RIPEMD-160, HMAC-MD5,HMAC-SHA- 1, and HMAC-RIPEMD-160.The designspace exploration ofthisunitisdoneusingtheHandelC language. Wepropose keyreuse mechanism forsuccessive messages inorder toimprove theHMAC throughput. In addition, weexplore thedesign space byproviding two implementations oftheHMAC algorithm, onefora general keysize andanother forafixed keysize. Ineach implementation, weusestandard keyuseandtheproposed keyreuse mechanisms, andthatresults infourdifferent implementations. The performance of thesefour implementations isanalyzed withrespect tothree design metrics: area, delay, andthroughput. We found that the proposed keyreusemechanism improves theHMAC throughput significantly whenalarge keyisreused, with negligible increase inareaanddelay. Inaddition, wefound that theimplementation ofHMAC forfixed keysize is better inarea, delay, andthroughput thantheHMAC implementation forgeneral keysize.