PQ-SecureMsg: A Post-Quantum Cryptography Based Messaging Framework for Web and Mobile

Quantum computing poses a serious threat to traditional cryptography, with algorithms like RSA and ECC being vulnerable to attacks such as Shor’s algorithm. To address this, we propose a Post-Quantum Secure Chat Application using lattice-based cryptography, specifically CRYSTALS-Kyber for key exchange and CRYSTALS-Dilithium for digital signatures. The system provides end-to-end encryption with forward secrecy, ensuring message confidentiality, authenticity, and integrity. Mathematical formulations of key encapsulation, encryption, and signature verification are presented, alongside performance benchmarks. Experimental results show that the application achieves practical latency and throughput on real devices while resisting quantum attacks. This work demonstrates that integrating post-quantum algorithms into messaging platforms is both feasible and essential for secure future communication.