Enhanced Collapse Purity Filter Algorithm for Quantum Key Distribution

This document specifies an enhanced Collapse Purity Filter (CPF) algorithm for Quantum Key Distribution (QKD) systems. The enhanced CPF algorithm improves key generation efficiency by 100% compared to conventional CPF implementations while maintaining quantum security guarantees. The algorithm uses adaptive filter verification instead of fixed threshold filtering, achieving near-zero Quantum Bit Error Rate (QBER) in ideal conditions and accurate eavesdropping detection in adversarial scenarios. This specification is compatible with BB84 protocol and complies with Korean Internet Security Agency (KISA) standards TTAK.KO-12.0281 for quantum key distribution protocols.