!CHAPTER The Simple Authentication App

The simple auth app provides hashed password-based authentication with automatically generated salts and constant-time password verification.

*Configuration*

* *saltLength* (optional): length of newly generated salts. Default: *16*.
* *hashMethod* (optional): hash algorithm to use. Supported values: *sha1*, *sha224*, *sha256*, *md5*. Default: *"sha256"*.

```js
var auth = Foxx.requireApp('/_auth').auth;
```

!SECTION Generate an authentication object

Generates an authentication object for a given password.

`auth.hashPassword(password)`

Returns an authentication object with the following properties:

* *hash*: the generated hex-encoded hash.
* *salt*: the salt used to generate the hash.
* *method*: the algorithm used to generate the hash.

*Parameter*

* *password*: the password to hash.

!SECTION Verify a password

Verifies a password against a given authentication object.

`auth.verifyPassword(authData, password)`

Generates a hash for the given password using the *salt* and *method* stored in the authentication object and performs a constant time string comparison on them. Returns *true* if the password is valid or *false* otherwise.

*Parameter*

* *authData*: an authentication object.
* *password*: a password to verify.