# `AttestoPhoenix.Verifier`
[🔗](https://github.com/XukuLLC/attesto_phoenix/blob/v2.13.0/lib/attesto_phoenix/verifier.ex#L1)

Host-facing OID4VP verifier API.

Presentation requests are persisted before their signed request object is
published. Wallet responses are verified by the public direct-post
controller, and hosts read the completed result once through
`presentation_result/2` (single-use: the read consumes the session).

Request objects continue to use the main `AttestoPhoenix.Config.keystore/1`; their protected
`alg` is derived from that key by `Attesto.JWS.sign_current`. The separate
verifier-encryption keystore is only an ECDH-ES recipient key and never
changes request-object signing policy.

# `create_attrs`

```elixir
@type create_attrs() :: %{
  :dcql_query => map(),
  :expected_query_ids => [String.t()],
  :issuer_trust => Attesto.PresentationSession.issuer_trust(),
  optional(:response_mode) => String.t(),
  optional(:client_id_scheme) => String.t()
}
```

# `create_result`

```elixir
@type create_result() :: %{
  id: String.t(),
  nonce: String.t(),
  client_id: String.t(),
  request_uri: String.t()
}
```

# `create_presentation_request`

```elixir
@spec create_presentation_request(AttestoPhoenix.Config.t(), create_attrs()) ::
  {:ok, create_result()} | {:error, term()}
```

Create a verifier presentation session and its signed request object.

The returned `id` is the OID4VP `state`; the absolute `request_uri` serves
the request object from the convention-derived verifier endpoint.

# `presentation_result`

```elixir
@spec presentation_result(AttestoPhoenix.Config.t(), String.t()) ::
  {:ok, map()} | :error
```

Read and consume the verified result of a completed presentation session.

Single-use: the completed session is removed on read, so the `response_code`
the browser carries to the completion page cannot be replayed to re-read the
presented claims. Returns `:error` on a second read, or an unknown, pending,
or expired session.

---

*Consult [api-reference.md](api-reference.md) for complete listing*