arXiv:2506.13261v2 Announce Type: replace-cross Abstract: The automotive industry trends to softwarizing cars according to flexible, service-oriented architectures. At the same time, connected cars become networked computer systems but lack proper security measures. In this paper, we propose to authenticate and authorize in-vehicle services by integrating DNSSEC, DANE, and DANCE with automotive middleware. Our approach decouples the cryptographic authentication of the service from that of the service deployment with the help of DNSSEC and thereby largely simplifies key management. We propose to authenticate in-vehicle services by certificates that are solely generated by the service suppliers but published on deployment via DNSSEC TLSA records solely signed by the OEM. We further show how these established Internet standards secure the service discovery and invocation, ensure interoperability with various protocols, and scale management of credentials for millions of connected vehicles at robust security levels. We back our design proposal by a security analysis using the STRIDE threat model and by evaluations in an emulation of a realistic in-vehicle setup that demonstrate its effectiveness.