Hardware aging-based software metering

Reliable and verifiable hardware, software and content usage metering (HSCM) are of primary importance for wide segments of e-commerce including intellectual property and digital rights management. We have developed the first HSCM technique that employs intrinsic aging properties of components in modern and pending integrated circuits (ICs) to create the first self-enforceable HSCM approach. There are variety of hardware aging techniques that range from electro-migration in wires to slow-down of crystal-based clocks. We focus on transistor aging due to negative bias temperature instability (NBTI) effects where the delay of gates increases proportionally to usage times. We address the problem of how we can measure the amount of time a particular licensed software (LS) is used by designing an aging circuitry and exposing it to the unique inputs associated with each LS. If a particular LS is used longer than specified, it automatically disables itself. Our novel HSCM technique uses a multi-stage optimization problem of computing the delays of gates, their aging degradation factors, and finally LS usage using convex programming. The experimental results show not just viability of the technique but also surprisingly high accuracy in the presence of measurement noise and imperfect aging models. HSCM can be used for many other business and engineering applications such as power minimization, software evaluation, and processor design.