KEF: A Key Exchange Framework for Operational Technology Security Standards and Guidelines

Recent findings show that many security standards and guidelines for Operational Technology (OT) in smart grids do not satisfy all key exchange properties such as mutual authentication, key secrecy, and key confirmation. As accepted best practices are undergoing tailoring due to increase in remote grid operations that have also led to an increase in cyber attacks against smart grids, we propose to enhance key exchange in the OT security standards and guidelines via KEF, a key exchange framework for satisfying and enforcing the key exchange security properties to mitigate cyber attacks. KEF comprises a set of cryptographic operations and a set of key exchange states for key exchange operations. We analyse the security of KEF using Automated Validation of Internet of Security Protocols and Applications (AVISPA) tool and demonstrate its security benefits by applying it to a real-world key establishment scheme, Special Publication (SP) 800-56A Revision 3, of the National Institute of Standards and Technology (NIST).