gistfile1.php

<?php

// auth.php
use lithium\security\Auth;
Auth::config([
	'auth' => [
		'adapter' => 'Form',
		'fields' => [
		  // this configuration does not work
			'email',
			'password',
			// neither is this
			'user[email]' => 'email',
			'user[password]' => 'password',
			// neither is this one
			'user.email' => 'email',
			'user.password' => 'password',
		],
		'scope' => [
			'active' => 1
		]
	]
]);

// MyController.php
class MyController extends \lithium\action\Controller {
	public function login() {
		if ($this->request->data) {
			return Auth::check('auth', $this->request) ?
				$this->redirect('Index::index') :
				['error' => 'Invalid login'];
		} else if (Auth::check('auth')) {
			return $this->redirect('Index::index');
		}
	}
}

// login.html.php
<?= $this->form->create(compact('user'), ['role' => 'form']); ?>
	<?= $this->form->field('user.email', [
		'type' => 'email',
		'template' => '{:input}',
		'class' => 'form-control',
		'placeholder' => 'you@example.com',
		'required' => 'required',
		'autofocus' => 'autofocus'
	]); ?>
	
	<?= $this->form->password('user.password', [
		'class' => 'form-control',
		'required' => 'required'
	]); ?>
	
	<?= $this->form->submit('Login', ['class' => 'btn btn-primary btn-lg btn-block']); ?>
<?= $this->form->end(); ?>