The trend towards web and cloud-based applications has produced a large number of different web portals and web services. secunet protect4use helps to implement a user-friendly and secure authentication system. It is a flexible client-server solution that provides both the user and the service operator with a diverse set of options for login. This includes secure multi-factor and multi-channel authentication. Identity information remains fully within the domain and sphere of control of the service provider at all times. secunet protect4use is browser-agnostic and operating system-agnostic, allowing the use of any token type supported by the relevant platform. To achieve this, the solution uses a method (patent pending) that permits not only authentication but also signatures and encryption.