Abstract—Joint Test Action Group (JTAG) interface is widely used in integrated circuits for functional testing and in-system debugging, ensuring high reliability throughout the silicon life cycle. However, it has also been identified as a potential vulnerability to the cyberattacks. Traditional security countermeasures such as adding authentication mechanism to restrict access to authorized users, often rely on uniform authentication credentials. This approach poses challenges for edge devices with varying computational capacities. Moreover, strengthening authentication security can lead to compatibility issues with embedded hardware on client devices, limiting scalability. To address these challenges, we propose Simple and Secure password authentication protocol, Light processing version based Joint Test Action Group plus Version (SASL-JTAG+), an enhanced JTAG authentication mechanism utilizing the Simple and Secure Password Authentication Protocol, Light Processing Version (SAS-L) protocol that enables one-time password authentication with adjustable bit lengths, tailored to the computational capacities of authenticators and target devices. The new approach provides robust security for devices with performance and cost constraints, offering flexible authentication data within a unified system. As a result, SASL-JTAG+ provides a scalable, long-term solution for securing IoT systems accommodating both legacy and modern devices while adapting to evolving technological demands.
 

Keywords—Internet of Things (IoT), edge devices, Cyber-Physical System (CPS), simple and secure password authentication protocol, Light Processing Version (SAS-L), Joint Test Action Group (JTAG), dependability