title: Full-field implementation of a perfect eavesdropper on a quantum cryptography system.
abstract: Quantum key distribution (QKD) allows two remote parties to grow a shared secret key. Its security is founded on the principles of quantum mechanics, but in reality it significantly relies on the physical implementation. Technological imperfections of QKD systems have been previously explored, but no attack on an established QKD connection has been realized so far. Here we show the first full-field implementation of a complete attack on a running QKD connection. An installed eavesdropper obtains the entire 'secret' key, while none of the parameters monitored by the legitimate parties indicate a security breach. This confirms that non-idealities in physical implementations of QKD can be fully practically exploitable, and must be given increased scrutiny if quantum cryptography is to become highly secure.
authors.affiliation: Centre for Quantum Technologies, Department of Physics, National University of Singapore, 3 Science Drive 2, Singapore 117543, Singapore.
authors.forename: Ilja
authors.initials: I
authors.lastname: Gerhardt
authors.forename: Qin
authors.initials: Q
authors.lastname: Liu
authors.forename: Antía
authors.initials: A
authors.lastname: Lamas-Linares
authors.forename: Johannes
authors.initials: J
authors.lastname: Skaar
authors.forename: Christian
authors.initials: C
authors.lastname: Kurtsiefer
authors.forename: Vadim
authors.initials: V
authors.lastname: Makarov
mesh_terms: D016494:Computer Security / Q000295:instrumentation*; D019544:Equipment Failure Analysis; D011789:Quantum Theory; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013685:Telecommunications / Q000295:instrumentation*