Hybrid Cloud Computing with Post-Quantum Cryptography and Advanced Hashing for Robust User Authentication in Healthcare Systems

The speedy evolution of cyber threats is a serious threat to the protection of sensitive health information, with increasing threats from quantum computing. Conventional security does not keep up with evolving threats, and innovative solutions are needed. This paper introduces a secure hybrid cloud architecture that combines post-quantum cryptography (PQC), advanced hashing, and quantum key distribution (QKD) to authenticate further and protect data in healthcare systems. The primary mission is to generate an attack-resistant authentication process, robust data integrity assurance, and a functional system for key management with extensibility and regulation compliance. The considered infrastructure utilizes PQC-based robust encryption, robust hashing to authenticate data integrity, and QKD for providing secure key exchange augmented with multi-factor authentication. Implementing quantum-resistant protocols properly secures healthcare data in public and private cloud centers. Performance testing reveals a 99.6% overall success rate, 99.8% key exchange success, and 99.9% detection accuracy with QKD. PQC integration offers robust encryption, and advanced hashing techniques offer tamper-evident data integrity. The results establish the strong security, scalability, and quantum age cyber threat tolerance of the approach as a secure solution for guarding healthcare applications and delivering confidential, integrity-guaranteeing data protection.