# Auth

Auth service helpers including nested profile access.

`client.auth` is the API-key identity surface. It exposes `me()` and nested `client.auth.profile`.

```rust
let me = client.auth.me().await?;
println!("{} {:?}", me.account_id, me.api_key_id);
println!("{:?}", me.root_smart_account_address);
```

The Account ID is sufficient identity for API-key auth. `username` may be absent/empty; do not reject the identity or substitute `"-"` as though it were required.

`me.api_key_id` is a base58 public ID for the authenticated key record. Request-signing `Config.api_key_id` and API-key metadata `key_id` values use the `ak_...` credential handle (including key CRUD in session clients that expose it). These identifiers have different representations and roles; do not compare them directly or pass the public ID as the signing handle.

## Profile identity stream

The Rust SDK deliberately omits profile get/update/history methods. The API-key-safe operation is:

```rust
let mut updates = client.auth.profile.subscribe_identity().await?;
if let Some(identity) = updates.recv_result().await? {
    println!("{} {}", identity.account_id, identity.username);
}
```

Wallet login, JWT refresh, MFA enrollment, and account resolve are **not** wrapped. API-key callers should configure `default_account_id` explicitly.

## Related

- [Authentication](https://testnet.polyester.com/docs/sdk/rust/guides/authentication)
- [Limitations](https://testnet.polyester.com/docs/sdk/rust/concepts/limitations-and-non-features)