Service discovery and secure and safe service usage are essential elements in the deployment of home and personal networks. Because no system administrator is present, setup and daily operation of such a network has to be automated as much as possible with a high degree of user friendliness. To achieve this goal many systems sacrifice security and privacy such, that services can be discovered and used unauthorized or a person's privacy may be breached. In this paper we present a security mechanism that seamlessly integrates with service discovery and usage. Exchange of keys and certificates is combined with messages used for service discovery. Services messages themselves are encrypted and authenticated, and casual receivers cannot read them. Although encryption and decryption of messages takes extra time, the combined protocol poses minimal communication overhead and hence can be used even in small devices.