Seamless Post-Quantum Transition: Agile and Efficient Encryption for Data-at-Rest

Federico Valbusa, Stephan Krenn, Thomas Lorünser, Thomas Lorünser, Sebastian Ramacher

2025

Abstract

As quantum computing advances, its threat to traditional cryptographic protocols, especially for long-term encrypted data, becomes critical. This paper presents an agile cryptosystem designed to ease the transition from pre-quantum to post-quantum security by supporting efficient integration of post-quantum Key Encapsulation Mechanisms (KEMs). Our approach combines a CCA-secure KEM with robust Authenticated Encryption (AE), allowing only the encapsulated key to be updated during migration, without re-encrypting large data payloads—saving both computation and bandwidth. We formalize cryptographic agility via an agile-CCA security model, ensuring that neither the original nor updated ciphertexts leak information. A game-based proof shows that the construction remains agile-CCA secure if the underlying KEM and AE are individually CCA-secure in the random oracle model. The result is a future-proof scheme that enables enterprises and cloud providers to safeguard vast data volumes against emerging quantum threats with minimal disruption.

Paper Citation

in Harvard Style

Valbusa F., Krenn S., Lorünser T. and Ramacher S. (2025). Seamless Post-Quantum Transition: Agile and Efficient Encryption for Data-at-Rest. In Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT; ISBN 978-989-758-760-3, SciTePress, pages 759-764. DOI: 10.5220/0013641000003979

in Bibtex Style

@conference{secrypt25,
author={Federico Valbusa and Stephan Krenn and Thomas Lorünser and Sebastian Ramacher},
title={Seamless Post-Quantum Transition: Agile and Efficient Encryption for Data-at-Rest},
booktitle={Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT},
year={2025},
pages={759-764},
publisher={SciTePress},
organization={INSTICC},
doi={10.5220/0013641000003979},
isbn={978-989-758-760-3},
}

in EndNote Style

TY - CONF

JO - Proceedings of the 22nd International Conference on Security and Cryptography - Volume 1: SECRYPT
TI - Seamless Post-Quantum Transition: Agile and Efficient Encryption for Data-at-Rest
SN - 978-989-758-760-3
AU - Valbusa F.
AU - Krenn S.
AU - Lorünser T.
AU - Ramacher S.
PY - 2025
SP - 759
EP - 764
DO - 10.5220/0013641000003979
PB - SciTePress