Spark FROST sign

Generate FROST partial signatures for one or more Bitcoin transaction sighashes using a key held in the Turnkey enclave.

type · enum<string> · required

Enum options: ACTIVITY_TYPE_SPARK_SIGN_FROST

timestampMs · string · required

Timestamp (in milliseconds) of the request, used to verify liveness of user requests.

organizationId · string · required

Unique identifier for a given Organization.

parameters · object · required

The parameters object containing the specific intent data for this activity.

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parameters.signatures · array · required

A batch of one or more signature requests. A single call can sign multiple transactions (e.g. branch + exit at deposit time, or up to 6 refund transactions per transfer).

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parameters.signatures.operatorCommitments · array · required

The FROST nonce commitments provided by each participating Spark Operator for this signature session. Each operator must provide both a hiding and binding commitment before signing begins.

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generateAppProofs · boolean

Enable to have your activity generate and return App Proofs, enabling verifiability.

A successful response returns the following fields:

activity · object · required

The activity object containing type, intent, and result

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cURL

curl --request POST \
  --url https://api.turnkey.com/public/v1/submit/spark_sign_frost \
  --header 'Accept: application/json' \
  --header 'Content-Type: application/json' \
  --header "X-Stamp: <string> (see Authorizations)" \
  --data '{
    "type": "ACTIVITY_TYPE_SPARK_SIGN_FROST",
    "timestampMs": "<string> (e.g. 1746736509954)",
    "organizationId": "<string> (Your Organization ID)",
    "parameters": {
        "signWith": "<spark-address>",
        "signatures": [
            {
                "derivation": {
                    "type": "SPARK_KEY_TYPE_SIGNING_HD",
                    "leafId": "<leaf-id>"
                },
                "message": "<sighash-hex>",
                "verifyingKey": "<aggregate-pubkey-hex>",
                "operatorCommitments": [
                    {
                        "id": "SO1",
                        "hiding": "<hiding-commitment-hex>",
                        "binding": "<binding-commitment-hex>"
                    }
                ]
            }
        ]
    }
}'

200

{
  "activity": {
    "id": "<activity-id>",
    "status": "ACTIVITY_STATUS_COMPLETED",
    "type": "ACTIVITY_TYPE_SPARK_SIGN_FROST",
    "organizationId": "<organization-id>",
    "timestampMs": "<timestamp> (e.g. 1746736509954)",
    "result": {
      "activity": {
        "id": "<string>",
        "organizationId": "<string>",
        "status": "<string>",
        "type": "<string>",
        "intent": {
          "sparkSignFrostIntent": {
            "signWith": "<spark-address>",
            "signatures": "<array>"
          }
        },
        "result": {
          "sparkSignFrostResult": {
            "signatures": [
              {
                "signatureShare": "<hex>",
                "hiding": "<hex>",
                "binding": "<hex>"
              }
            ]
          }
        },
        "votes": "<array>",
        "fingerprint": "<string>",
        "canApprove": "<boolean>",
        "canReject": "<boolean>",
        "createdAt": "<string>",
        "updatedAt": "<string>"
      }
    }
  }
}