Seifert's RSA Fault Attack: Simplified Analysis and Generalizations

Seifert recently described a new fault attack against an implementation of RSA signature verification. Here we give a simplified analysis of Seifert’s attack and gauge its practicality against RSA moduli of practical sizes. We suggest an improvement to Seifert’s attack which has the following consequences: if an adversary is able to cause random faults in only 4 bits of a 1024-bit RSA modulus stored in a device, then there is a greater than 50% chance that they will be able to make that device accept a signature on a message of their choice. For 2048-bit RSA, 6 bits suffice.