After finishing the studies of computer science in 2001 with a diploma (master) degree, Thomas worked at the university as a systems administrator for five years. In this time, he was able to work on his doctorate (Ph.D.), which he finished in 2006. Thomas was employed at Siemens CERT for penetration tests, which he improved over the years. The main targets of his tests are all Siemens products, from Industry, Energy, Healthcare and Communications.