> ## Documentation Index
> Fetch the complete documentation index at: https://docs.world.org/llms.txt
> Use this file to discover all available pages before exploring further.

# Authenticator Reference

export const Nullifier = () => {
  return <Tooltip tip="The nullifier is a one-time use token which is used to ensure a single action is performed only once.">
            Nullifier
        </Tooltip>;
};

export const RpRegistry = () => {
  return <Tooltip tip="The Relying Party Registry is a smart contract where RPs can register before using the Protocol.">
            Relying Party Registry
        </Tooltip>;
};

export const UniquenessProof = () => {
  return <Tooltip tip="A Uniqueness Proof is a proof that the user has only performed the action once">
            Uniqueness Proof
        </Tooltip>;
};

export const AuthenticatorSDK = () => {
  return <Tooltip tip="The Authenticator SDK is called WalletKit">
            <a href="https://github.com/worldcoin/walletkit" target="_blank" rel="noopener noreferrer">
                Authenticator SDK
            </a>
        </Tooltip>;
};

## Authenticator Requests & Responses

This section describes how authenticators receive and respond to requests from RPs. This also reflects what is implemented in the <AuthenticatorSDK />.

The authenticator receives a request from an RP in the following format.

### Request Schema

The schema for the request is defined in the `world-id-primitives` crate as [`ProofRequest`](https://docs.rs/world-id-primitives/latest/world_id_primitives/request/struct.ProofRequest.html).

### Request Examples

<Tabs>
  <Tab title="Single Credential">
    ```json theme={null}
    {
      "id": "req_18c0f7f03e7d",
      "version": 1,
      "created_at": "1771612953",
      "expires_at": "1771613013",
      "rp_id": "rp_0000000000000000000000000000000000001",
      "action": "0x0000000000000000000000000000000000000000000000000000000000000001",
      "nonce": "0x11d223ce7b91ac212f42cf50f0a3439ae3fcdba4ea32acb7f194d1051ed324c2",
      "signature": "304502205cce35752b1642327bebf9f203960dc83f92fa919a4567981ce0c157060ca04e022100f328e42ff2609ddc1fbc7da17896ded2687acb3a4eeb8847a6f3a87ce50ed016",
      "requests": [
        {
          "identifier": "passport",
          "issuer_schema_id": 9303,
          "signal": "abcd-efgh-ijkl"
        }
      ]
    }
    ```
  </Tab>

  <Tab title="Multiple Credentials">
    ```json theme={null}
    {
      "id": "req_18c0f7f03e7d",
      "version": 1,
      "created_at": "1771612953",
      "expires_at": "1771613013",
      "rp_id": "rp_0000000000000000000000000000000000001",
      "action": "0x0000000000000000000000000000000000000000000000000000000000000001",
      "nonce": "0x11d223ce7b91ac212f42cf50f0a3439ae3fcdba4ea32acb7f194d1051ed324c2",
      "signature": "304502205cce35752b1642327bebf9f203960dc83f92fa919a4567981ce0c157060ca04e022100f328e42ff2609ddc1fbc7da17896ded2687acb3a4eeb8847a6f3a87ce50ed016",
      "requests": [
        {
          "identifier": "passport",
          "issuer_schema_id": 9303,
          "signal": "abcd-efgh-ijkl"
        },
        {
          "identifier": "poh",
          "issuer_schema_id": 1,
          "signal": "abcd-efgh-ijkl"
        }
      ],
      "constraints": {
        "all": ["passport", "poh"]
      }
    }
    ```
  </Tab>

  <Tab title="More Complex Constraints">
    ```json theme={null}
    {
      "id": "req_18c0f7f03e7d",
      "version": 1,
      "created_at": "1771612953",
      "expires_at": "1771613013",
      "rp_id": "rp_0000000000000000000000000000000000001",
      "action": "0x0000000000000000000000000000000000000000000000000000000000000001",
      "nonce": "0x11d223ce7b91ac212f42cf50f0a3439ae3fcdba4ea32acb7f194d1051ed324c2",
      "signature": "304502205cce35752b1642327bebf9f203960dc83f92fa919a4567981ce0c157060ca04e022100f328e42ff2609ddc1fbc7da17896ded2687acb3a4eeb8847a6f3a87ce50ed016",
      "requests": [
        {
          "identifier": "passport",
          "issuer_schema_id": 9303,
          "signal": "abcd-efgh-ijkl"
        },
        {
          "identifier": "my-number-card",
          "issuer_schema_id": 9310,
          "signal": "mnop-qrst-uvwx"
        },
        {
          "identifier": "orb",
          "issuer_schema_id": 1,
          "signal": "abcd-efgh-ijkl"
        }
      ],
      "constraints": {
        "all": [
          "orb",
          {
            "any": ["passport", "my-number-card"]
          }
        ]
      }
    }
    ```
  </Tab>
</Tabs>

### Constraint Evaluation

When using the `any` constraint, the order of credential types in the array determines **priority order**. The authenticator will attempt to provide the first available credential type in the list. If that credential is not available, it will fall back to the next type in the array, and so on.

<Note>
  Priority ordering only applies to `any` constraints. For `all` constraints,
  all specified credential types must be provided regardless of order.
</Note>

**Example**:

```json theme={null}
{
  "constraints": { "any": ["poh", "passport"] }
}
```

In this case:

* If the user has an PoH credential, the authenticator will provide it.
* If the user does not have an PoH credential but has a passport credential, the authenticator will provide the passport instead.
* The PoH credential type has priority over passport.

This priority mechanism allows RPs to request their preferred credential type while still accepting fallback options if the preferred type is unavailable.

### Response Schema

The schema for the response is defined in the `world-id-primitives` crate as [`ProofResponse`](https://docs.rs/world-id-primitives/latest/world_id_primitives/request/struct.ProofResponse.html).

### Response Examples

<Tabs>
  <Tab title="Success (OK)">
    ```json theme={null}
    {
    "id": "req_18c0f7f03e7d",
    "version": 1,
    "responses": [
        {
            "identifier": "orb",
            "issuer_schema_id": 1,
            "proof": "0x0000000000000000000000000000000000000000000000000000000000000000000000000",
            "nullifier": "nil_00000000000000000000000000000000000000000000000001"
        }
    ]
    }
    ```
  </Tab>

  <Tab title="Failure (Constraints Not Satisfied)">
    ```json theme={null}
    {
        "id": "req_18c0f7f03e7d",
        "version": 1,
        "error": "constraints_not_satisfied",
        "responses": []
    }
    ```
  </Tab>

  <Tab title="Success with Session (OK)">
    ```json theme={null}
    {
    "id": "req_18c0f7f03e7d",
    "version": 1,
    "responses": [
        {
            "identifier": "orb",
            "issuer_schema_id": 1,
            "proof": "0x0000000000000000000000000000000000000000000000000000000000000000000000000",
            "session_nullifier": "00000000000000000000000000000000000000000000000001"
        }
    ]
    }
    ```
  </Tab>
</Tabs>