Practical QCA-inspired quantum encryption with BB84 key distribution for NISQ devices

Reference implementation and reproducibility materials for the manuscript "Practical QCA-Inspired Quantum Encryption with BB84 Key Distribution for NISQ Devices" (Soumya S and T. Chithralekha, Department of Computer Science, Pondicherry University). The deposit contains the protocol implementation (BB84 key layer, QCA-inspired encryption/decryption, and the tag-based integrity-verification mechanism), the controlled-depolarising and backend-calibrated noise models, and a single reproducibility notebook that regenerates every table and figure in the manuscript from a fixed random seed (SEED = 42). No external datasets are used; all reported quantities are generated by simulation.