Dr. Michael Marhöfer is affiliated with Nokia Siemens Networks, Network Technology. He is a computer engineer by training (Ph.D. TU Karlsruhe, post-doc at Stanford University) In Siemens AG, he began at Central Research, with contributions to CAD for VLSI and various other research topics. Later, he was responsible for the evolution of the Siemens PKI, adding extensions for B2B e-commerce, before he joined the mobile communication business. There he was responsible for technology management and various security-related projects in services access control, DRM and trusted computing applications for telecommunications services. In Nokia Siemens Networks he is a senior expert, currently responsible for applications of Identity Management between network operators and internet applications.