A practical split manufacturing framework for trojan prevention via simultaneous wire lifting and cell insertion

Trojans and backdoors inserted by untrusted foundries have become serious threats to hardware security. Split manufacturing is proposed to prevent Trojan insertion proactively. Existing methods depend on wire lifting to hide partial circuit interconnections, which usually suffer from large overhead and lack of security guarantee. In this paper, we propose a novel split manufacturing framework that not only guarantees to achieve the required security level but also allows for a drastic reduction of the introduced overhead. In our framework, insertion of dummy circuit cells and wires is considered simultaneously with wire lifting. To support cell and wire insertion, we propose a new security criterion, and further derive its sufficient condition to avoid computation intensive operations in traditional methods. Then, for the first time, a novel mixed integer linear programming formulation is proposed to simultaneously consider cell and wire insertion together with wire lifting, which significantly enlarges the design space to guarantee the realization of the sufficient condition under the security requirements and overhead constraints. With extensive experimental results, our framework demonstrates much better efficiency, overhead reduction, and security guarantee compared with existing methods.