Function prepare_ecdsa_signature 

pub fn prepare_ecdsa_signature(
    msg: Word,
    sig: &Signature,
) -> Result<Vec<Felt>, PublicKeyError>

Infers the pubic key from the provided signature and message, and encodes this public key and signature into a vector of field elements in the format expected by stdlib::crypto::dsa::ecdsa::secp256k1::verify_ecdsa_k256_keccak procedure.

See encode_ecdsa_signature() for more info.

Errors

Returns an error if key recovery from signature and message fails.