Split-fabrication obfuscation: Metrics and techniques

Split-fabrication has been proposed as an approach for secure and trusted access to advanced microelectronics manufacturing capability using un-trusted sources. Each wafer to be manufactured is processed by two semiconductor foundries, combining the front-end capabilities of an advanced but untrusted semiconductor foundry with the back-end capabilities a trusted semiconductor foundry. Since the security of split fabrication relates directly to a front-end foundry's ability to interpret the partial circuit designs it receives, metrics are needed to evaluate the obfuscation of these designs as well as circuit design techniques to alter these metrics. This paper quantitatively examines several “front-end” obfuscation techniques and metrics inspired by information theory, and evaluates their impact on design effort, area, and performance penalties.