Fault Analysis Attacks on Control Statement of RSA Exponentiation Algorithm

Many research results show that RSA system mounted using conventional binary exponentiation algorithm is vulnerable to some physical attacks. Recently, Schmidt and Hurbst demonstrated experimentally that an attacker can exploit secret key using faulty signatures which are obtained by skipping the squaring operations. Based on similar assumption of Schmidt and Hurbst's fault attack, we proposed new fault analysis attacks which can be made by skipping the multiplication operations or computations in looping control statement. Furthermore, we applied our attack to Montgomery ladder exponentiation algorithm which was proposed to defeat simple power attack. As a result, our fault attack can extract secret key used in Montgomery ladder exponentiation.