preSign
Precomputes the message-independent part of a signature for fast finalization. ECDSA only — the native EdDSA and Taproot libraries expose no presign session, so on those algorithms this throws UnsupportedOperationException.
Runs the expensive three-party work ahead of time; once the message is known, preSignFinal turns the result into a full signature with far less latency. Each pre-signature is single-use — generate a fresh one per signature.
Return
the pre-signature bytes, to pass to preSignFinal.
Parameters
keyId
the hex-encoded keyId to precompute against; the SDK reads the share from its StorageClient.
See also
to finalize with a message.