proveoffchain.md

proveOffChain

Description

The proveOffChain method generates an off-chain proof for a ZPass credential, executing the program locally without submitting to the blockchain. The program can be both deployed on-chain or a local program that is not deployed on-chain but is provided and agreed upon by all the involved parties (issuer, user, verifier).

Parameters

• options (ProveOffChainOptions): An object containing:
  • localProgram (string): The Aleo program source code
  • functionName (string): Name of the function to execute
  • inputs (string[]): Array of input parameters for the function
  • offlineQuery (OfflineQuery, optional): An optional offline query object used to insert the global state root and state paths needed to create a valid inclusion proof offline.

Returns

Returns a Promise that resolves to an object containing:

• outputs (string[]): Array of function outputs
• execution (string): The execution trace
• verifyingKey (string): The verifying key for the proof

Example

const { outputs, execution, verifyingKey } = await zpass.proveOffChain({
    localProgram: programSource,
    functionName: functionName,
    inputs: [signature, `{
      issuer: ${issuer},
      subject: ${subject},
      dob: ${dob},
      nationality: ${nationality},
      expiry: ${expiry}
    }`,
      `{ salt: ${salt} }`,
    ],
});