IntroductionBy 2030, an estimated 40% of current cloud infrastructures may be rendered vulnerable by cryptanalytically relevant quantum computers (CRQCs).MethodsThis paper introduces a 4-tier security framework tailored for Quantumas-a-Service (QaaS) deployments, focusing on securing data-in-transit. Integrating 3 NIST-standardized post-quantum algorithms (ML-KEM, ML-DSA, and SLHDSA), our architecture mitigates interception threats based on Shor's algorithm.ResultsEmulation across an enterprise cloud topology demonstrates a maximum latency overhead of 17.7 milliseconds per TLS handshake under high-latency WAN conditions, ensuring high-availability operations without catastrophic fragmentation failure.DiscussionThe proposed model demonstrates the viability of modern latticebased cryptography for live environments and provides a structured 3-phase transition roadmap for cloud service providers (CSPs) to achieve quantum-resilience seamlessly.