title: Handheld free space quantum key distribution with dynamic motion compensation.
abstract: Mobile devices have become an inseparable part of our everyday life. They are used to transmit an ever-increasing amount of sensitive health, financial and personal information. This exposes us to the growing scale and sophistication of cyber-attacks. Quantum Key Distribution (QKD) can provide unconditional and future-proof data security but implementing it for handheld mobile devices comes with specific challenges. To establish security, secret keys of sufficient length need to be transmitted during the time of a handheld transaction (~1s) despite device misalignment, ambient light and user's inevitable hand movements. Transmitters and receivers should ideally be compact and low-cost, while avoiding security loopholes. Here we demonstrate the first QKD transmission from a handheld transmitter with a key-rate large enough to overcome finite key effects. Using dynamic beam-steering, reference-frame-independent encoding and fast indistinguishable pulse generation, we obtain a secret key rate above 30kb/s over a distance of 0.5m.
authors.forename: Hyunchae
authors.initials: H
authors.lastname: Chun
authors.forename: Iris
authors.initials: I
authors.lastname: Choi
authors.forename: Grahame
authors.initials: G
authors.lastname: Faulkner
authors.forename: Larry
authors.initials: L
authors.lastname: Clarke
authors.forename: Bryan
authors.initials: B
authors.lastname: Barber
authors.forename: Glenn
authors.initials: G
authors.lastname: George
authors.forename: Colin
authors.initials: C
authors.lastname: Capon
authors.forename: Antti
authors.initials: A
authors.lastname: Niskanen
authors.forename: Joachim
authors.initials: J
authors.lastname: Wabnig
authors.forename: Dominic
authors.initials: D
authors.lastname: O'Brien
authors.forename: David
authors.initials: D
authors.lastname: Bitauld