Quantum cryptography

Quantum cryptography offers protocols whose security can be proven directly from information-theoretic principles and the laws of quantum mechanics, and which do not rely on any assumptions about the computational resources available to an adversary. We have achieved pioneering advances in quantum secure communication. In Stockholm, we were the first to demonstrate quantum key distribution (QKD) at 1550 nm over 40 km. We later proposed new high-dimensional QKD protocols with full security analysis against quantum computers. We developed and patented novel secret sharing methods, including the first experimental single-qubit five-party scheme, and demonstrated multi-user QKD over optical fiber. Our work introduced quantum authentication protocols and fault-tolerant multiparty solutions with recent optical fiber implementations. We also conducted security tests, exposing vulnerabilities in QKD systems using avalanche photodetectors, enabling undetectable attacks. Finally, our contributions to quantum random number generation, including a Bell inequality–based QRNG, gained international recognition for enhancing online security.

Selected publications