public function beforeSave(){
    $salt = "Acrec_$";
    $hashed = hash('sha512', $salt . $this->password);
    $this->password = $hashed;
}

$this->auth->check([
    'email' => $this->request->getPost('email'),
    'password' => $this->request->getPost('password'),
    'remember' => $this->request->getPost('remember')
]);