The increasing complexity of automotive networks has led to broad security issues related to human safety. On the other hand, to solve problems of network overload, the automotive world is moving in the direction of using an Ethernet backbone for in-vehicle communications. Therefore, the security of Ethernet protocols for such applications has become a significant concern. The IEEE 802.1X-2010 standard could be a suitable solution for the key management of Ethernet-based encrypted communications. In this work, an efficient hardware accelerator for the intensive sections of the IEEE 802.1X-2010 is presented. The system was synthesized both on a Stratix V FPGA and on a 40 nm standard-cell library. The former gives a usage of 3% of the Adaptive Logic Modules (ALMs) while the latter shows an occupation of 55 kgates. On the FPGA, the maximum throughput is 152 Mbps and 1.14 Gbps for the two considered sections of the standard while the standard-cell technology provides a maximum throughput of 457 Mbps and 3.85 Gbps. Results show that this architecture represents a fast and low-area key management solution for Ethernet networks in automotive applications.