SEQUANCES: Deciphering the Vulnerabilities of Quantum Cryptography Systems
量子密码学基于量子物理定律，与依赖数学方法的传统密码学及后量子密码学本质不同。当前主流协议量子密钥分发（QKD）允许双方安全交换加密密钥，保障数据机密性与完整性。由CEA-Leti牵头、自2023年初启动的三年期卡诺SEQUANCES项目，核心正是针对QKD系统的光学-数字接口，研究可能的物理攻击，以深化技术认知并推动其成熟。
该接口负责光子探测与处理，项目重点评估其是否构成漏洞，尤其是否易受侧信道观察攻击——这一方向在科学文献中鲜有探讨。研究取得重要进展，显著提升了CEA-Leti在量子密码学领域的专业能力，并且与法国国家科研署通过Quantum PEPR计划资助的QCommTestbed倡议形成互补。QCommTestbed汇聚包括CEA-Leti在内的九家合作伙伴，旨在构建法国协调统一的量子技术国家测试平台。
Quantum cryptography derives its security from the laws of quantum physics, distinguishing it from post-quantum cryptography (PQC) and conventional mathematical approaches. A core protocol, Quantum Key Distribution (QKD), allows two parties to exchange encryption keys with guaranteed confidentiality and integrity.
The Carnot SEQUANCES project, a three-year initiative led by CEA-Leti since early 2023, focused on a poorly understood aspect of QKD systems: the optical-to-digital interface where photons are detected and processed. The project investigated whether this boundary could be exploited through side-channel observation attacks—a vulnerability that had received scant attention in scientific literature. Its goal was to characterize such physical threats and advance the technology's maturity.
SEQUANCES yielded significant insights into the optical-to-digital interface, bolstering CEA-Leti's quantum cryptography expertise. These results complement the QCommTestbed effort, an ANR-funded project under the Quantum PEPR program that unites nine partners to build a coordinated national testing platform for quantum technologies in France.
Quantum cryptography should not be confused with post-quantum cryptography (PQC). Unlike PQC and conventional cryptography, which rely on mathematical approaches, the security of quantum cryptography is based on the laws of quantum physics.
One of the main quantum cryptography protocols currently in use is Quantum Key Distribution (QKD). This method enables two users to exchange encryption keys, allowing them to securely encrypt and decrypt the data they share while preserving confidentiality and integrity.
This was precisely the focus of the three-year Carnot SEQUANCES project, led by CEA-Leti since early 2023. Its primary objective was to characterize potential physical attacks targeting the optical-to-digital interface of QKD systems, with the goal of advancing knowledge of the technology and contributing to its maturity.
What exactly is the optical-to-digital interface?
The question was whether this interface could represent a vulnerability exploitable by attackers.
The project therefore investigated whether photon detection and processing could be subject to so-called side-channel observation attacks.
These questions had received very limited attention in the scientific literature until now.
The SEQUANCES project delivered important results for understanding the optical-to-digital interface of QKD systems. It has significantly strengthened CEA-Leti's expertise in quantum cryptography, complementing another initiative, QCommTestbed, funded by the French National Research Agency (ANR) through the Quantum PEPR program.
QCommTestbed brings together nine partners, including CEA-Leti, with the objective of establishing a coordinated national testing platform for quantum technologies in France.
https://www.lereseaudescarnot.fr/en
The SEQUANCES project characterized physical side-channel attacks on the optical-to-digital interface of Quantum Key Distribution (QKD) systems, addressing a little-studied vulnerability to advance the technology’s maturity.
Monitor — results fill a research gap and may influence QKD security standards as the technology moves toward deployment.