mR_LWE-CP-ABE: a Recoverable CP-ABE protocol for Post-quantum Cryptography
This talk presents a novel lattice-based revocable CP-ABE scheme built upon lattice-based cryptography to addresses the challenge of efficient user revocation in post-quantum secure cloud environments by leveraging semi-trusted mediators to enable multi-step decryption without costly re-encryption.
Overview
Ciphertext-Policy Attribute-Based Encryption (CP-ABE) is a powerful cryptographic paradigm enabling fine-grained access control over encrypted data, making it particularly well-suited for cloud environments and privacy-preserving applications. However, efficiently revoking user access without requiring costly re-encryption remains a critical challenge, especially in post-quantum secure settings.
In this talk, we present mR_LWE-CP-ABE, a novel revocable CP-ABE scheme built upon lattice-based cryptography. The proposed solution extends over Zhang and Zhang Dual-Regev CP-ABE construction by introducing a server-aided mechanism, ensuring fine-grained access control while remaining in a post-quantum safe environment. Unlike traditional CP-ABE schemes, which typically rely on pairings and suffer from revocation inefficiencies, mR_LWE-CP-ABE leverages a network of semi-trusted security mediators to enable multi-step decryption without requiring ciphertext re-encryption.
In details, after introducing the notion of CP-ABE (along with its advantages and criticalities), we detail the theoretical foundations of our approach based on the Learning With Errors (LWE) assumption, and demonstrate its security against selective chosen-plaintext attacks under the framework of indistinguishability games (IND-sCPA). Additionally, we provide experimental results from our prototype implementation built upon the Palisade cryptographic library, evaluating the overhead introduced by the revocation mechanism w.r.t.\ the original model. Our findings suggest that mR_LWE-CP-ABE offers a scalable and efficient solution for secure cloud-based data sharing in a post-quantum setting.
Presenters
Dr. Elia Onofri, Researcher, The Institute of Applied Mathematics of the National Research Council of Italy
Brief Biography
Elia Onofri earned his Ph.D. in Mathematics from the University of Roma Tre (Italy) in October 2023, following a Bachelor’s in Mathematics and a Master’s in Computational Sciences. He is currently a researcher at IAC—CNR, focusing on mathematical and numerical modelling for applied sciences.
His core expertise lies in cryptography, graph theory, high-performance computing, machine learning, and theoretical computer science while his recent research has expanded into Security & Privacy and computational biology. He was actively involved in the European project ERA4TB, contributing to mathematical and computational models for understanding tuberculosis evolution and treatment strategies, and currently collaborates in different national projects, including H2IOSC, a collaborative cluster of European distributed research infrastructures involved in the humanities and cultural heritage sectors. His research activities extend across four countries, where he collaborates with multiple international research groups. In addition to his research commitments, Elia is an adjunct professor at Roma Tre University, where he teaches Cryptography, Algorithms and Data Structures, Python Programming, and Combinatorial Optimisation and where he supervised Bachelor’s, Master’s, and Ph.D. students in cryptography and machine learning. Elia is also a member of Italian cryptography association “De Componendis Cifris", engaged in cryptographic research and dissemination, and concurrently organised and chaired national and international initiatives on applied mathematics.