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

# Authentication

| [`Authenticate`](./atoti.authentication.authenticate#atoti.Authenticate)                                                                                            | Called with the URL of a request and return the HTTP headers necessary to authenticate it.                                                                                                                                      |
| ------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [`BasicAuthentication`](./atoti.authentication.basic_authentication#atoti.BasicAuthentication)                                                                      | Authenticate requests with [basic authentication](https://en.wikipedia.org/wiki/Basic_access_authentication).                                                                                                                   |
| [`ClientCertificate`](./atoti.authentication.client_certificate#atoti.ClientCertificate)                                                                            | A client certificate to [`connect()`](./atoti.Session.connect#atoti.Session.connect) to a session configured with [`ClientCertificateConfig`](./atoti.config.security.client_certificate_config#atoti.ClientCertificateConfig). |
| [`OAuth2ResourceOwnerPasswordAuthentication`](./atoti.authentication.oauth2_resource_owner_password_authentication#atoti.OAuth2ResourceOwnerPasswordAuthentication) | Authenticate requests with OAuth 2's [Resource Owner Password Credentials Grant](https://datatracker.ietf.org/doc/html/rfc6749#section-4.3).                                                                                    |
| [`TokenAuthentication`](./atoti.authentication.token_authentication#atoti.TokenAuthentication)                                                                      | Authenticate requests by passing the given token in the Authorization header.                                                                                                                                                   |