On the implementation of a fast prime generation algorithm

Abstract

A side-channel analysis of a cryptographic algorithm generally concentrates on the encryption or decryption phases, rarely on the key generation phase. In this paper, we show that, when not properly implemented, the fast prime generation algorithm proposed by Joye and Paillier at CHES 2006 is susceptible to side-channel analysis; its main application is the generation of RSA key-pairs for embedded platforms like smart-cards. Our attack assumes that some parity bit can be recovered through SPA when it appears in a branch condition. Our attack can be combined with Coppersmith's theorem to improve its efficiency; we show that for 1024-bit RSA moduli, one can recover the factorization of roughly 1/1000 of the RSA moduli. © Springer-Verlag Berlin Heidelberg 2007.