Pool Entropy and Examination Integrity: An End-to-End Security Architecture for High-Stakes Public Examinations

High-stakes public examinations fail through question-paper leakage at a rate that has resisted decades of procedural reform. This paper argues that the failure is architectural rather than administrative. Examination systems create a single static secret and hold it for weeks. They pass it through hundreds of hands, then rely on custody controls to protect it. Those controls fail whenever one custodian chooses to defect. We take pool entropy as the governing security parameter for examination integrity. The relationship between item-pool size and form overlap is already established in the measurement literature. This paper inverts it, so that the scale of an insider compromise can be inferred from an observed leak. It is applied to the 2026 NEET-UG cancellation, the largest in Indian history, which affected 2.27 million candidates. The inference implies compromise of roughly seventy percent of the live pool. We derive a per-cell entropy floor, and a retirement rule bounding how many administrations a pool may serve. That rule shows that indefinite reuse eventually yields the entire form, irrespective of custody quality. We then present a nine-stage security architecture spanning item authorship to result publication. Cryptographic and statistical mechanisms replace procedural trust at every stage. An explicit technology-readiness assessment separates components deployable today from those requiring further research. A phased implementation model is calibrated to institutional capability rather than to a fixed timetable. Section 16 states plainly which mechanisms are inherited from published work and which are claimed as original. The work is grounded in the Indian examination system, which offers the largest and best-documented evidence base available. The architecture itself is jurisdiction-neutral. It addresses failure patterns documented across Algeria, Bangladesh, Brazil, China, Kenya, Nigeria, Russia, South Korea, Turkey, the United Kingdom, the United States and Vietnam. The framework is separated into jurisdiction-independent invariants and country-specific instantiations. A set of custodial role archetypes allows the architecture to be instantiated under any governance structure.