Quantum-lattice synergy: a next-generation blueprint for post-quantum cloud security

Quantum computing poses a fundamental threat to the classical cryptographic mechanisms that underpin contemporary cloud security, motivating an urgent transition toward post-quantum solutions. This study introduces Quantum-Lattice Synergy (QLS), a next-generation security blueprint that integrates the computational hardness of lattice-based cryptography with the information-theoretic guarantees of quantum cryptographic primitives. QLS is a mix of Learning with Errors (LWE)-based encryption, quantum key distribution (QKD), and quantum-generated randomness to offer robust and scalable with resilience to future protection of cloud infrastructures. The architecture consists of three modules which are closely interrelated, namely, QLS-KG to generate quantum-lattice hybrid keys, QLS-Enc for lattice-based encryption with quantum-derived keys, and QLS-Auth to achieve secure authentication with quantum hashing and lattice trapdoors. Through rigorous mathematical modelling, security proofs and complexity analysis, it has been demonstrated that QLS provides a dual-layered defence which provides, at the computational level, computational security based on hard lattice problems, and at the physical level, physical security based on quantum mechanics. It has been experimentally shown that QLS is more efficient in key generation, encryption, and decryption compared to the state-of-the-art post-quantum protocols, such as LWE-based encryption, NTRU Encrypt, and Kyber512, depending on the quantum-assisted keying and parameterizing lattices, and achieving the same level of classical symmetric-key security at 256 bits. This characterization of security is not intended to mean an AES-256 baseline or to exclude the ability of existent schemes to meet similar security levels in the right configurations, it simply indicates that QLS has a strength in its hybrid, defence-in-depth architecture. QLS is created in a way that it can be deployed in the context of existing cloud facilities, which tackles durability of confidentiality, future economics, scalability and reliability of trust during the post-quantum era.