Paper 2025/2183 Original: eprint.iacr.org/2025/2183 ↗
Hardware Implementation of Stealthy and Lightweight Backdoor for CRYSTALS-Kyber
Abstract
The threat of practical quantum attacks has catapulted viable alternatives like Post-Quantum Cryptography (PQC) into prominence. The adoption and integration of standardized PQC primitives across the entire digital stack are promoted by various standardization bodies, governments, and major corporate houses. A serious challenge in quantum migration is to ensure that there is no hidden backdoor in the PQC implementations of a hybrid cryptosystem (support for both pre-quantum and post-quantum algorithms), which are often procured from a third-party vendor. In this manuscript, we investigate the possibility of a kleptographic backdoor on the NIST-recommended key-encapsulation mechanism CRYSTALS-Kyber. The modified Kyber key-generation algorithm achieves indistinguishable decryption failure probability compared to the original CRYSTALS-Kyber. The kleptographic module is also implemented in FPGA, embedded inside the CRYSTALS- Kyber accelerator with a very low area overhead (283 LUTs or 2% of total area), and thus can easily pass performance and functionality tests.
Metadata
- Available format(s)
PDF- Category
- Attacks and cryptanalysis
- Publication info
- Preprint.
- History
- 2025-12-02: last updated
- 2025-12-02: published
- Short URL
- https://ia.cr/2025/2183
- License
- https://creativecommons.org/licenses/by/4.0/
BibTeX
@misc{cryptoeprint:2025/2183,
author = {Suraj Mandal and Prasanna Ravi and M Dhilipkumar and Debapriya Basu Roy and Anupam Chattopadhyay},
title = {Hardware Implementation of Stealthy and Lightweight Backdoor for CRYSTALS-Kyber},
howpublished = {Cryptology {ePrint} Archive, Paper 2025/2183},
year = {2025},
url = {https://eprint.iacr.org/2025/2183}
}