When signing the same message, all EdDSA implementations are supposed to reuse the same `r`, as per RFC 8032, and thus to produce the same signature under the s

When signing the same message, all EdDSA implementations are supposed to reuse the same `r`, as per RFC 8032, and thus to produce the same signature under the same key. For smartphone and instant messaging, I wouldn't be worried about fault attacks, there are probably easier ways around it.