The authors present a use case of the introduction of a large scale Public Key Infrastructure (PKI) environment in an incumbent telecommunications company. The main characteristics of the case are the integration of an existing physical access facility with a PKI environment for logical security of the company ICT infrastructure. In fact, both are accessed using a single (smart) company card. The purpose was to implement a high level of security, within the practical constraints at hand, and to reach a level of reduced sign-on for company employees. This integration poses numerous challenges. In this paper they describe how PKI is actually introduced to support authentication, signing and encryption services for its employees.