On the Figures of Merit for Quantum Software Security: Toward a Benchmarking Rubric

Quantum software is increasingly provided through multi-tenant and cloud-based Quantum-as-a-Service (QaaS) stacks. A growing concern about the diverse attack vectors across the pipeline has been demonstrated in recent research. Yet the community has converged on three mature pillars: Scale (Qubit Count), Quality (Quantum Volume), and Speed (Circuit Layer Operations per Second (CLOPS)) for the merit performance figures. Moreover, it has also begun to define software-quality metrics. However, the security of quantum software remains largely unmeasured. A few quantitative security indicators, such as Total Variation Distance (TVD) and Degree of Functional Corruption (DFC), exist. Although they were introduced ad hoc for individual circuit obfuscation techniques, they are incompatible. We assert that the security of quantum software deserves the same attention as the performance: an explicit set of Security Figures of Merit (S-FoMs). The research of this paper is threefold: (i) characterizes a three-layer measurement gap, (ii) proposes a structured S-FoM set organized by ISO/IEC 25010 security sub-characteristics, QaaS pipeline mapping, and measurement maturity, and (iii) defines a benchmarking rubric that normalizes and aggregates S-FoMs into a combined Quantum Software Security Posture (QSSP) score. Additionally, an illustrative reanalysis of published obfuscation techniques has been presented. Our aim is a first step toward security-aware benchmarking of the Quantum Software Stack (QSS).