A Commitment-Based Hybrid Post-Quantum Cryptographic Model for Multi-File Cloud Storage

Computer Science > Cryptography and Security [Submitted on 13 Aug 2026] A Commitment-Based Hybrid Post-Quantum Cryptographic Model for Multi-File Cloud Storage Lemdi Frank Prikutse, Regina Esi Turkson, Alimatu-Saadia Yussiff, Abdul-Lateef Yussiff, Maame G. Asante-Mensah Cloud storage clients increasingly require authentication that remains secure against future quantum-capable adversaries, motivating hybrid constructions that combine classical primitives with standardized post-quantum alternatives. Extended naively to multi-file upload, such constructions incur a per-file lattice signing cost that dominates authentication time and becomes prohibitive at realistic batch sizes. This paper presents a commitment-based hybrid post-quantum model that addresses this bottleneck. It comprises AES-256-GCM bulk encryption, a hybrid X25519 with ML-KEM-768 key encapsulation mechanism, and a hybrid Ed25519 with ML-DSA-65 dual signature, computed over a SHA3-256 batch commitment. The commitment binds all ciphertexts in a batch to a single fixed-size digest that is signed once, reducing the number of post-quantum signature invocations per batch from n to one, independent of batch size; the remaining encryption and hashing is bounded by fast symmetric throughput. On a commodity client platform, averaged over 20 repetitions, this holds signing-phase time near-constant as the batch grows while the per-file baseline scales linearly. At n = 1000, the model reduces signing-phase time by factors of 629, 606, and 725 for 100 KB, 1 MB, and 10 MB files respectively, against a per-file dual-signing baseline sharing every other primitive. Subjects: Cryptography and Security (cs.CR) Cite as: arXiv:2608.13138 [cs.CR]   (or arXiv:2608.13138v1 [cs.CR] for this version)   https://doi.org/10.48550/arXiv.2608.13138 Focus to learn more Submission history From: Lemdi Frank Prikutse [view email] [v1] Thu, 13 Aug 2026 12:14:54 UTC (889 KB) Access Paper: view license Current browse context: cs.CR < prev   |   next > new | recent | 2026-08 Change to browse by: cs References & Citations NASA ADS Google Scholar Semantic Scholar Export BibTeX Citation Bookmark Bibliographic Tools Bibliographic and Citation Tools Bibliographic Explorer Toggle Bibliographic Explorer (What is the Explorer?) Connected Papers Toggle Connected Papers (What is Connected Papers?) Litmaps Toggle Litmaps (What is Litmaps?) scite.ai Toggle scite Smart Citations (What are Smart Citations?) Code, Data, Media Demos Related Papers About arXivLabs Which authors of this paper are endorsers? | Disable MathJax (What is MathJax?)