According to the polkadot.js docs, both
ecdsa signatures are deterministic (given the message and private key, it always produces the same signature). However
sr25519 is not.
I understand a nonce value is usually required to sign a message. It's the source of the randomness of the signature. We can use the RFC6979 trick in
ecdsa to generate deterministic nonce, but why cannot we use the same trick in