# Authentication

- [YubiKey & FIDO2 SSH Authentication](https://docs.gotempest.app/authentication/yubikey-fido2-ssh-authentication.md): Use a YubiKey or any FIDO2 security key to authenticate SSH in Tempest on Mac, Windows, Linux — no agent or PAM module, works with ed25519-sk keys.
- [Post-Quantum SSH Algorithms (PQC)](https://docs.gotempest.app/authentication/post-quantum-ssh-algorithms.md): Tempest supports post-quantum SSH key exchange (ML-KEM, SNTRUP761) with a one-click toggle between PQ and legacy algorithm sets.


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# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://docs.gotempest.app/authentication.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.