SEABASS: Symmetric-keychain encryption and authentication for building automation systems

Abstract

There is an increasing security risk in Building Automation Systems (BAS) in that its communication is unprotected, resulting in the adversary having the capability to inject spurious commands to the actuators to alter the behaviour of BAS. The communication between the Human-Machine-Interface (HMI) and the controller (PLC) is vulnerable as there is no secret key being used to protect the authenticity, confidentiality and integrity of the sensor data and commands. We propose SEABASS, a lightweight key management scheme to distribute and manage session keys between HMI and PLCs, providing a secure communication channel between any two communicating devices in BAS through a symmetric-key based hash-chain encryption and authentication of message exchange. Our scheme facilitates automatic renewal of session keys periodically based on the use of a reversed hash-chain. A prototype was implemented using the BACnet/IP communication protocol and the preliminary results show that the symmetric keychain approach is lightweight and incurs low latency.

Formal Security Analysis and Improvement Based on LonTalk Authentication Protocol

“…Under the development of technology, there are increasingly articles pointing out that the LonTalk authentication protocol in building automation system has many vulnerabilities [6]. Literature [7][8][9][10][11][12] points out that the LonTalk authentication protocol has the following security vulnerabilities: (1) this authentication protocol only supports verifying the identity of the sender and cannot check the identity of the receiver. Only the sender can initiate the challenge-answer request; however, the receiver cannot, so the protocol can only carry out one-way authentication.…”