Cornelius is into multi factor authentication since 2004. He is the project lead of the multi factor authentication system privacyIDEA.

As a consultant Cornelius learnt to unterstand customers requirements in heterogenous networks first hand. He planned and implemented several public key infrastructures for smartcard usage and was one of the first to work on the interoperability of the Aladdin eToken between Windows and Linux.

In 2006 he started one of the the first open source one time password systems implementing the HOTP algorithm. In 2009 he initiated an enterprise OTP solution as product manager. In 2014 he kicked off the open source privacyIDEA project. It is a vendor independent authentication system, which can be used to manage arbitrary authentication objects to implement many different ways of multi factor authentication. privacyIDEA suppors several authentication protocols like PAM, RADIUS, SAML or LDAP. In 2014 Cornelius also founded the company NetKnights to provide consultancy for strong and secure authentication.

During the last years Cornelius spoke at several conferences in Germany, in the Netherlands, in Belgium, in Denmark and in the U.S.