# Secure Shell Access {#sec-ssh}

Secure shell (SSH) access to your machine can be enabled by setting:

```nix
{ services.openssh.enable = true; }
```

By default, root logins using a password are disallowed. They can be
disabled entirely by setting
[](#opt-services.openssh.settings.PermitRootLogin) to `"no"`.

You can declaratively specify authorised public keys for a user
as follows:

```nix
{
  users.users.alice.openssh.authorizedKeys.keys = [ "ssh-ed25519 AAAAB3NzaC1kc3MAAACBAPIkGWVEt4..." ];
}
```