Finding invalid signatures in pairing-based batches

Abstract

This paper describes efficient methods for finding invalid digital signatures after a batch verification has failed. We present an improvement to the basic binary "divide-and-conquer" method, which can identify an invalid signature in half the time. We also present new, efficient methods for finding invalid signatures in some pairing-based batches with low numbers of invalid signatures. We specify these methods for the Cha-Cheon signature scheme of [5]. These new methods offer significant speedups for Cha-Cheon batches as well as other pairing-based signature schemes. © Springer-Vorlag Berlin Heidelberg 2007.