The main topic of this diploma paper is a single sign on solution to a Java application with smartcards. A problem in today's commercial world is the administration of passwords to each application. In this case it is difficult to memorize all the passwords on there own. The consequence of this is a security problem by noting passwords in uncertain and insecure places. The small notes stuck everywhere on the computer are the result of this shortcoming.

Our task was to develop a single sign on solution that only needs one authentication to several applications. The authentication is made thereby with a Smartcard. A user can log in with a certificate on his Smartcard. If the registration is successful, the user is permitted to use all applications which are connected to the registration. In our diploma paper applications where developed to encrypt and decrypt files and connect to a server with a safe SSL connection.

For the single sign on solution some tools where needed to develop the applications. The cryptographic applications for authentication and encryption were realized with the CryptoAPI by Windows whereby these were implemented with MS Visual Studio 6,0 in the language C. Because Java cannot use the CryptoAPI functions directly a solution had to be found to include the C-functions into a Java application. This task was realized by Java native interface. A further, very useful tool is the JAAS (Java Authentication and Authorization Service) from SUN. This is a tool to authenticate and authorize users to an application. In this diploma paper the login modul was written and used for the authentication of the developed Java application. Authorizing of users is so far developed on a provisional basis that may be completed and implemented easily in a later stage.