Methodological Dimensions of Post-Quantum Cost Estimation
Quantifying migration expenditures for financial institutions demands an integrated methodology that bridges economic estimation and structural risk indexing under deep technological uncertainty. The methodological framework developed in this study synthesizes parametric cost modeling with risk-based prioritization to resolve the institutional invisibility of legacy cryptographic debt. In alignment with the four-basis epistemological taxonomy (Towards a Defensible Framework for Post-quantum Cryptography Cost Estimation, 2026), the estimation model organizes expenditure across parametric, theoretical, analogical, and judgmental classes. This cross-class triangulation provides robust empirical defensibility because each basis addresses distinct facets of cryptographic lifecycle management, from internal certificate inventories to regulatory capital implications. To ensure that capital allocations prioritize the most vulnerable payment architectures, the costing engine incorporates the Quantum Risk Index formulation (Towards a Quantum Risk Index, 2026). This structural index quantifies compromise probability across surface, exposure, scale, and persistence dimensions while evaluating asset degradation across confidentiality, integrity, and authenticity metrics. Furthermore, the estimation model accommodates timeline compression dynamics where automated analytical capabilities alter discovery and planning phases, shifting expenditure constraints toward non-compressible regulated verification cycles (Mythos-Class Frontier Models and the Compression of Post-Quantum Cryptography Migration Timelines, 2026). Hierarchical aggregation maps these technical risk coefficients directly into enterprise business process budgets, enabling institutional decision-makers to evaluate residual risk against marginal security expenditure. By establishing explicit perimeter boundaries that distinguish controlled assets from third-party terminations, the methodology generates verifiable capital forecasts that satisfy supervisory mandates while systematically eliminating cryptographic inertia across banking systems.