Researchers from Xi’an Jiaotong-Liverpool University have set a new global milestone in post-quantum cryptography (PQC) by cracking Kyber-256-k1 in the Bochum Challenges, the highest-known challenge.

This breakthrough in lattice-based cryptanalysis, which provides crucial empirical data for verifying the security margins of PQC standards, was recorded in March at the 2026 Real-World PQC Workshop.

It is the latest in a string of achievements for XJTLU’s Post-Quantum Migration Interdisciplinary Laboratory(PQC-X), led by Professor Jintai Ding, which earlier solved the SVP-200 and SVP-210 and the Kyber-208 challenge.

“Only by mastering the art of the attack can we build a stronger defence,” says Professor Ding, whose team specialises in subjecting existing mathematical perimeters to high-intensity stress tests to validate their reliability.

Rapid advancements in quantum computing pose a major threat to traditional public-key cryptographic systems. Today, malicious actors are intercepting and storing sensitive data encrypted with existing algorithms to decrypt later once large-scale quantum computers become available.

To mitigate this, numerous countries have initiated PQC migration strategies, such as lattice-based cryptography, favoured for its efficiency and robust security. In the United States, the Kyber algorithm has been standardised by the National Institute of Standards and Technology as ML-KEM (FIPS 203), establishing it as the core defence against future quantum computing capabilities.

Defensive line

To crack Kyber-256-k1, rather than using massive supercomputing clusters, the XJTLU team deployed a level of computing power that is far from large-scale and faced with complex cryptographic structures, the researchers reconstructed the mathematical transformation architecture, introduced novel hardware acceleration technologies that exponentially boosted computing efficiency, and refined the final computational workflow.

After rigorous data iteration, the team succeeded in a controlled experimental environment. It demonstrates that even with highly optimised algorithms and concentrated computational effort, researchers could only painstakingly conquer this specific challenge parameter (Kyber-256-k1). Ultimately, this achievement serves as empirical validation of the standard's overall security, proving that the complete Kyber standard is exceptionally robust and maintains an ample security margin.

Rui Liu, Deputy Director of the PQC-X lab, explained that probing the true security baselines of algorithms is essential to building a “quantum defensive line”.

“Only by clarifying the protective capabilities of cutting-edge algorithms can we safely advance the comprehensive migration and upgrade of existing digital defences to a post-quantum cryptographic system,” he says. “The goal is to ensure the long-term security of digital information and empower the sustained development of the digital economy.”

By Qinru Liu

Edited by Patricia Pieterse