Generate a proof

A relying party asks for a World ID proof by sending a proof request. This page shows how a WalletKit app answers it with a registered account. To register an account and store credentials first, see Accounts and credentials.

Before you begin

• Enable the embed-zkeys feature, which provides the proving keys. See Install WalletKit.
• Open the account’s CredentialStore. See The credential store.

Answer a proof request

The following Rust function opens the account, binds its storage, and answers a proof request. The Swift, Kotlin, and browser APIs take the same steps with the same names in their own casing.

#![allow(unused)]
fn main() {
use std::sync::Arc;

use walletkit::authenticator::artifacts::embedded::EmbeddedZkArtifacts;
use walletkit::requests::ProofRequest;
use walletkit::storage::CredentialStore;
use walletkit::{Authenticator, Environment};

async fn prove(
    seed: Vec<u8>,
    store: Arc<CredentialStore>,
    request_json: &str,
    now: u64,
) -> Result<String, Box<dyn std::error::Error>> {
    let authenticator = Authenticator::init_with_defaults(
        seed,
        None, // rpc_url: use the default.
        &Environment::Staging,
        None, // region: use the default.
        Arc::new(EmbeddedZkArtifacts::new()),
        store,
    )
    .await?;
    authenticator.init_storage(now)?;

    let request = ProofRequest::from_json(request_json)?;
    let response = authenticator.generate_proof(&request, Some(now)).await?;
    Ok(response.to_json()?)
}
}

In this function, now is the current time in Unix seconds. Send the JSON that it returns back to the relying party.

On iOS and Android, use CachingZkArtifacts instead of EmbeddedZkArtifacts when the keys are compressed, so that WalletKit decompresses them only once.

Legacy World ID 3.0 proofs

The v3 feature adds the World ID 3.0 API in the v3 module. The Swift and Kotlin packages include it; the browser package doesn’t. docs.rs builds the crate without v3, so read its documentation in the v3 module source or with cargo doc --features v3.