Low-level signing

Without the crypto feature, mpckit exposes the on-chain signing flow as three direct methods. You drive the centralized signature math from your own crypto pipeline and feed bytes back to the backend.

let prepare = api.sign_prepare(/* args */).await?;
let submit  = api.sign_submit(/* args */).await?;
let req     = api.get_sign_request(&submit.sign_request_id).await?;

Stages

Prepare

let prepare = api.sign_prepare(SignPrepareArgs {
    dwallet_id: dwallet_id.into(),
    curve: Curve::Secp256k1,
    signature_algorithm: SignatureAlgorithm::EcdsaSecp256k1,
    hash_scheme: Hash::Sha256,
}).await?;

The backend mints a presign (off-chain attestation) and returns the session id plus the bytes you need for the centralized math.

Submit

let submit = api.sign_submit(SignSubmitArgs {
    sign_session_id: prepare.sign_session_id.clone(),
    user_message_bytes: /* output of your centralized sign step */,
    message: message.to_vec(),
}).await?;

The backend submits the on-chain sign session and returns the sign_request_id.

Poll

use mpckit::SignRequestStatus;

loop {
    let req = api.get_sign_request(&submit.sign_request_id).await?;
    match req.status {
        SignRequestStatus::Completed => break req.signature.expect("signed"),
        SignRequestStatus::Failed => return Err(/* surface error */),
        _ => tokio::time::sleep(std::time::Duration::from_millis(500)).await,
    }
}

Once status is Completed, req.signature holds the raw signature bytes. Encoding to a chain-native format is your responsibility.

Idempotency

SignSubmitArgs accepts an idempotency_key: Option<String>. Pass a UUID-v7 (use new_idempotency_key()) so a retried sign_submit returns the original sign_request_id instead of triggering a second on-chain session.