21Nis
Is it possible to verify that two different signatures of the same message came from the same private key?
Knowing that ECDSA signatures are non-deterministic (barring RFC 6979), is it possible to verify that two different, yet valid signatures of the same message came from the same private key?
To provide an example: let's say Bob receives a valid signature from Alice and stores Alice's public key. If Alice, after some time, sends a different (yet valid) signature of the same message made with the same private key, can Bob verify the signature using the stored public key and be certain that only Alice generated this new signature given the same private key was used to create it?
