HLock: Locking IPs at the High-Level Language

The introduction of the horizontal business model for the semiconductor industry has introduced trust issues for the integrated circuit supply chain. The most common vulnerabilities related to intellectual properties can be caused by untrusted third-party vendors and malicious foundries. Various techniques have been proposed to lock the design at the gate-level or RTL before sending it to the untrusted foundry for fabrication. However, such techniques have been proven to be easily broken using SAT attacks and machine learning-based attacks. In this paper, we propose HLock, a framework for ensuring hardware protection in the form of locking at the high-level description of the design. Our approach includes a formal analysis of design specifications, assets, and critical operations to determine points in which locking keys are inserted. The locked design is then synthesized using high-level synthesis, which has become an integral part of modern IP design due to its advantages on lesser development and verification efforts. The locking at the higher abstraction with the combination of multiple syntheses shows that HLock delivers superior performance considering attack resiliency (i.e., SAT attack, removal attacks, machine learning-based attacks) and overheads compared to conventional locking techniques. Additionally, HLock provides a dynamic/automatic locking solution for any high-level abstraction design based on performance constraints, attack resiliency, power, and area overheads as well as locking key size, and it is well suited for large-scale designs.