Override laravel 4's authentication methods to use custom hasing function

I have a table in my database with users. Their password are generated with my own custom hashing function.

How do i override the Authentication methods in laravel 4 to use my own hash class?

This is what I have been trying to do:

    class CustomUserProvider implements Illuminate\Auth\UserProviderInterface {


    public function retrieveByID($identifier)
    {
        return $this->createModel()->newQuery()->find($identifier);
    }

    public function retrieveByCredentials(array $credentials)
    {
        // First we will add each credential element to the query as a where clause.
        // Then we can execute the query and, if we found a user, return it in a
        // Eloquent User "model" that will be utilized by the Guard instances.
        $query = $this->createModel()->newQuery();

        foreach ($credentials as $key => $value)
        {
            if ( ! str_contains($key, 'password')) $query->where($key, $value);
        }

        return $query->first();
    }

    public function validateCredentials(Illuminate\Auth\UserInterface $user, array $credentials)
    {
        $plain = $credentials['password'];

        return $this->hasher->check($plain, $user->getAuthPassword());
    }

}

class CodeIgniter extends Illuminate\Auth\Guard {


}

App::bind('Illuminate\Auth\UserProviderInterface', 'CustomUserProvider');



Auth::extend('codeigniter', function()
{
    return new CodeIgniter( App::make('CustomUserProvider'), App::make('session'));
});

When I run the Auth::attempt method I get this error: ErrorException: Warning: Illegal offset type in isset or empty in G:\Dropbox\Workspaces\www\video\vendor\laravel\framework\src\Illuminate\Foundation\Application.php line 352