sbt_mintPrivate

sbt_mintPrivate submits a zkSBT issuance transaction and handles proof attachment, issuer authorization, and note commitment updates in one call. It is tailored for credential programs that prefer RPC automation over direct extrinsic crafting.

Parameters

Parameter	Type	Required	Description
schemaId	string	Yes	Identifier for the zkSBT schema being minted.
recipientCommitment	string	Yes	Commitment representing the recipient’s zkAddress note.
proof	string	Yes	Proof generated via zk_generateProof.
expiry	number	Optional	Unix timestamp after which the credential is invalid.
metadata	object	Optional	Encrypted metadata blob for off-chain reference.

Returns

Field	Type	Description
extrinsicHash	string	Hash of the submitted mint extrinsic.
blockHash	string	Block that included the credential issuance.
noteCommitment	string	The finalized commitment stored on-chain.

Request Example

{
 "jsonrpc": "2.0",
 "method": "sbt_mintPrivate",
 "params": [{
 "schemaId": "zksbt:kyc-tier2",
 "recipientCommitment": "0x6f36...",
 "proof": "0x8f4c...",
 "expiry": 1767225600,
 "metadata": {
 "encrypted_reference": "0x01ab..."
 }
 }],
 "id": 11
}

Workflow

1. Generate the proof client-side with zk_generateProof.
2. Invoke sbt_mintPrivate with the proof and encrypted metadata.
3. Track the returned extrinsicHash using author_submitExtrinsic or chain_getBlock to confirm inclusion.
4. Notify the recipient to rescan their zkAddress wallet for the new credential note.

Errors

Code	Meaning	Fix
-43001	Issuer unauthorized	Ensure issuer keys are registered in the zkSBT pallet.
-43002	Proof invalid	Regenerate proof and confirm schema matches.
-43003	Recipient missing	Validate the recipient’s commitment before submission.

Use state_getStorage to audit minted credentials and revocation state for ongoing compliance.