# Authentication

Learn how to authenticate users and secure the database with the SurrealDB PHP SDK.

Since SurrealDB is a database that is designed to be used in a distributed environment, it is important to secure the database and the data that is stored in it.
SurrealDB provides a number of methods for authenticating users and securing the database.

## Define scope

If you haven't defined a scope for your database, you can define a scope by quering to the database using the [`query`](/docs/reference/php/v1/methods/query.md) method.

```php
$db->query('
	DEFINE SCOPE user SESSION 24h
	SIGNUP ( CREATE user SET email = $email, pass = crypto::argon2::generate($pass) )
	SIGNIN ( SELECT * FROM user WHERE email = $email AND crypto::argon2::compare(pass, $pass) );
');
```

In `2.0` and above, the `DEFINE SCOPE` Statement has been replaced with the `DEFINE ACCESS ... TYPE RECORD` Statement so the above query would be:

```php
$db->query('
DEFINE ACCESS user ON DATABASE TYPE RECORD
	SIGNUP ( CREATE user SET email = $email, pass = crypto::argon2::generate($pass) )
	SIGNIN ( SELECT * FROM user WHERE email = $email AND crypto::argon2::compare(pass, $pass) )
	DURATION FOR TOKEN 15m, FOR SESSION 12h
;
');
```

## Signup with credentials

To signup a new scoped user, you can use the [`signup`](/docs/reference/php/v1/methods/signup.md) method from the `Surreal` class. This method takes an associative array
with the `namespace`, `database`, and `scope` keys as arguments. The `email` and `pass` keys are also required for this example, but it can be different
depending on the required parameters you have defined for the scope.

```php
$db->signup([
	"namespace" => "surrealdb",
	"database" => "surrealdb",
	"scope" => "user",
	"email" => "user@email.com",
	"pass" => "password-123"
]);
```

```php
// 2.0 and above
$db->signup([
	"namespace" => "surrealdb",
	"database" => "surrealdb",
	"access" => "user",
	"email" => "user@email.com",
	"pass" => "password-123"
]);
```

## Signin with credentials

To signin with credentials, you can use the [`signin`](/docs/reference/php/v1/methods/signin.md) method.

**Root**

Root authentication gives you access to all namespaces and databases within the SurrealDB instance.
		```php
		$token = $db->signin([
			"username" => "root",
			"password" => "secret"
		]);
		```

**Namespace**

Namespace authentication gives you access to all databases within a particular namespace.
		```php
		$token = $db->signin([
			"username" => "root",
			"password" => "secret",
			"namespace" => "surrealdb"
		]);
		```

**Database**

Database authentication gives you access to all data within a single database.
		```php
		$token = $db->signin([
			"username" => "root",
			"password" => "secret",
			"namespace" => "surrealdb",
			"database" => "surrealdb"
		]);
		```

**Scope**

Authenticate using a specific [Scope](/docs/reference/query-language/statements/define/scope.md) within a database.
		```php
		$token = $db->signin([
			"email" => "user@email.com",
			"pass" => "secret",
			"namespace" => "surrealdb",
			"database" => "surrealdb",
			"scope" => "user"
		]);
		```

**Access**

Authenticate using a specific [access method](/docs/reference/query-language/statements/define/access.md) within a database.
		```php
		$token = $db->signin([
			"email" => "user@email.com",
			"pass" => "secret",
			"namespace" => "surrealdb",
			"database" => "surrealdb",
			"access" => "user"
		]);
		```

## Signin with auth token

If you already have signed in and have an auth token stored somewhere, you can authenticate using the [`authenticate`](/docs/reference/php/v1/methods/authenticate.md) method.
This method takes one argument, the auth token.

```php
$db->authenticate($token);
```

## User information

When you signed in successfully, you can get the user information by using the [`info`](/docs/reference/php/v1/methods/info.md) method.
This returns the user information as an associative array.

```php
$user = $db->info();
```

## Invalidate user session

To invalidate a user session, you can use the [`invalidate`](/docs/reference/php/v1/methods/invalidate.md) method. When executed, the user
session will be invalidated and the user will be signed out.

```php
$db->invalidate();
```

In the next article we will cover how to query to the database.