Practical fault injection on deterministic signatures: The case of EdDSA

Abstract

After recent vulnerabilities of implementations of deterministic signatures e.g. EdDSA have been revealed, it became evident that a secure deployment of those will require additional countermeasures. Nevertheless, this is not a simple task, as we show in this work. We demonstrate the easiness of fault attacks on EdDSA as implemented in the lightweight cryptographic library WolfSSL on a 32-bit micro-controller. We achieve a success rates of almost 100% by voltage glitching and electromagnetic fault injection. Even after adding certain checks as a countermeasure, the implementation remains vulnerable to fault injection. As only a single successful fault is needed to recover the key, this kind of implementation is an easy target for the attackers.