CROSSING researcher Barbara Benedikt was recognised for her single-author paper “Reducing the Number of Qubits in Solving LWE”, which addresses a challenge in the field of quantum cryptanalysis: the high qubit requirements of quantum attacks on lattice-based cryptography systems like the Learning-With-Errors (LWE) problem.

LWE is a math problem that forms the backbone of many cryptographic schemes thought to be safe from quantum attacks, as for example the recently standardized schemes Kyber and Dilithium. Previous research showed how quantum computers could, in theory, solve LWE faster, but only with an enormous amount of quantum bits (qubits) that is not realistically available anytime soon. However, Barbara Benedikt’s research challenges the assumption that such large amounts of qubits are required to break the encryption. In her work, she could significantly reduce the number of qubits needed to solve LWE problems through the use of so-called generalized Dicke states.

The result is a quantum attack on LWE that brings theory closer to what might one day be possible in hardware. While the research is theoretical, its impact is very real. Barbara Benedikt’s work helps the cryptography community to better judge which encryption systems are truly secure in a future with quantum computers, which will be crucial for protecting everything from personal messages to health records and financial transactions. Her work on generalized Dicke states could become an useful tool to attack other math problems.

The PQCrypto 2025 program featured 25 peer-reviewed papers spanning topics from code-based and lattice-based cryptography to quantum cryptanalysis and migration strategies. Among them, two more papers from CROSSING researchers.