POST-QUANTUM CRYPTOGRAPHY INTEGRATED WITH ZERO-TRUST ARCHITECTURES FOR FUTURE SECURE CLOUD COMPUTING SYSTEMS

Abstract

The rapid development of quantum computing presents a critical threat to conventional public-key cryptographic mechanisms used in cloud infrastructures, while increasingly distributed cloud services continue to expose organizations to identity-based, insider, and lateral-movement attacks. This study proposes a future-oriented secure cloud computing framework that integrates post-quantum cryptography with zero-trust architecture to provide quantum-resistant data protection, continuous identity verification, least-privilege access, micro-segmentation, and adaptive policy enforcement. A simulation-based methodology was used to model a multi-tenant cloud environment containing users, virtual machines, application services, data repositories, and potentially compromised access nodes. The proposed framework employed lattice-based key encapsulation and digital-signature mechanisms for secure session establishment, authentication, and data exchange, while the zero-trust layer evaluated device status, user identity, behavioral risk, location, and service sensitivity before granting access. Its performance was compared with a conventional cloud security model using classical cryptography and perimeter-based access control. Simulated results showed that the integrated framework improved unauthorized-access detection from 82.4% to 96.8%, reduced successful lateral-movement attempts by 71.6%, and decreased credential-based compromise by 64.3%. The framework achieved a threat-detection accuracy of 95.2%, precision of 94.6%, recall of 95.8%, and F1-score of 95.2%. It also maintained 99.1% secure-session establishment under simulated quantum-capable attack conditions, compared with 61.7% for the conventional model. The additional security mechanisms increased average authentication latency from 42 ms to 58 ms and produced a 13.6% computational overhead; however, these costs remained within acceptable limits for cloud-based applications. Furthermore, encryption throughput reached 91.4% of the baseline system, while policy-based access violations were reduced by 68.9%. Security effectiveness remained stable across varying workloads, tenant densities, and simulated attack intensities, indicating consistent protection without significant degradation during peak cloud operations. The findings demonstrate that combining post-quantum cryptography with zero-trust principles can substantially strengthen cloud resilience against both present and future cyber threats. The proposed framework provides a scalable foundation for quantum-safe identity management, secure service communication, and continuous risk-aware access control in next-generation cloud computing systems.