Experimental measurement-device-independent quantum digital signatures

The development of quantum networks will be paramount towards practical and secure telecommunications. These networks will need to sign and distribute information between many parties with information-Theoretic security, requiring both quantum digital signatures (QDS) and quantum key distribution (QKD). Here, we introduce and experimentally realise a quantum network architecture, where the nodes are fully connected using a minimum amount of physical links. The central node of the network can act either as a totally untrusted relay, connecting the end users via the recently introduced measurement-device-independent (MDI)-QKD, or as a trusted recipient directly communicating with the end users via QKD. Using this network, we perform a proof-of-principle demonstration of QDS mediated by MDI-QKD. For that, we devised an efficient protocol to distil multiple signatures from the same block of data, thus reducing the statistical fluctuations in the sample and greatly enhancing the final QDS rate in the finite-size scenario

Ultra-high bandwidth quantum secured data transmission

Quantum key distribution (QKD) provides an attractive means for securing communications in optical fibre networks. However, deployment of the technology has been hampered by the frequent need for dedicated dark fibres to segregate the very weak quantum signals from conventional traffic. Up until now the coexistence of QKD with data has been limited to bandwidths that are orders of magnitude below those commonly employed in fibre optic communication networks. Using an optimised wavelength divisional multiplexing scheme, we transport QKD and the prevalent 100 Gb/s data format in the forward direction over the same fibre for the first time. We show a full quantum encryption system operating with a bandwidth of 200 Gb/s over a 100 km fibre. Exploring the ultimate limits of the technology by experimental measurements of the Raman noise, we demonstrate it is feasible to combine QKD with 10 Tb/s of data over a 50 km link. These results suggest it will be possible to integrate QKD and other quantum photonic technologies into high bandwidth data communication infrastructures, thereby allowing their widespread deployment

Quantum key distribution with hacking countermeasures and long term field trial

Quantum key distribution's (QKD's) central and unique claim is information theoretic security. However there is an increasing understanding that the security of a QKD system relies not only on theoretical security proofs, but also on how closely the physical system matches the theoretical models and prevents attacks due to discrepancies. These side channel or hacking attacks exploit physical devices which do not necessarily behave precisely as the theory expects. As such there is a need for QKD systems to be demonstrated to provide security both in the theoretical and physical implementation. We report here a QKD system designed with this goal in mind, providing a more resilient target against possible hacking attacks including Trojan horse, detector blinding, phase randomisation and photon number splitting attacks. The QKD system was installed into a 45 km link of a metropolitan telecom network for a 2.5 month period, during which time the system operated continuously and distributed 1.33 Tbits of secure key data with a stable secure key rate over 200 kbit/s. In addition security is demonstrated against coherent attacks that are more general than the collective class of attacks usually considered

Muistisairauksia potevien ihmisten fyysinen kuntoutus

Tämän toiminnallisen opinnäytetyön tarkoituksena oli järjestää liikuntatuokio muistisairauksia poteville ihmisille. Tavoitteena oli antaa asukkaille ja henkilökunnalle ohjeita oikeanlaiseen kuntouttavaan liikuntaan muistisairauksia potevia ihmisiä ajatellen. Tämän lisäksi kokosimme henkilökunnalle kuvallisen kansion sekä teoriatietoa, jotta he voisivat myöhemmin hyödyntää suunnittelemiamme liikuntaharjoitteita. Opinnäytetyön tilaajana oli yksityinen hoitokoti Villa Fredrika. Tapahtuma toteutettiin 16.5.2013 yksityisessä hoitokodissa Villa Fredrikassa Hyvinkäällä. Osallistujia oli yhteensä 21, iältään 75-91-vuotiaita. Kolme osallistujista oli pyörätuolissa. Ryhmä jaettiin viiteen osaan ohjaamisen helpottamiseksi. Kullekin ryhmälle oli varattu aikaa noin 30 minuuttia. Kokonaisuudessaan tilaisuus kesti noin 5 tuntia. Liikuntatuokioon olimme valinneet kolme pääteemaa, lihaskunto-, tasapaino- ja kestävyysharjoitukset. Lisäksi lopussa pidimme rentoutushetken. Tilaisuuden onnistumista arvioimme kyselylomakkeella, jotka täytettiin yhdessä osallistujien kanssa heti kunkin ryhmän jälkeen. Myös osa henkilökunnasta täytti kyselyn. Arviointilomakkeet asukkaille ja henkilökunnalle olivat hieman erilaiset. Kyselylomake oli kvantitatiivinen eli määrällinen. Tuloksia tarkastellen toimintapäivä oli onnistunut hyvin sekä ohjauksen että liikunnan osalta.People with memory disorders and their physical rehabilitation The purpose of the thesis was to organize an exercise event to people with memory disorders. The objective was to give directions for right rehabilitative exercise to the residents and staff. In addition, we made a graphical folder of exercise for the staff to be used later. The study was commissioned by the private nursing home Villa Fredrika. The event took place on 16th of May 2013 in the private nursing home Villa Fredrika in Hyvinkää. Overall 21 residents took part in the event. They were aged 75-91. Three of them were in wheel chairs. The group was divided in five to make tutoring easier. Every group took time about 30 minutes. In the exercise event we had chosen three main themes, muscle, balance and durability exercises. At the end we had a relaxation moment. The success of the event was assessed with by a questionnaire which was filled together with the participants right after each group. Also part of the staff filled it. The questionnaires of the staff and the residents were different. The study was quantitative. The result showed, that the day was a success as well as guidance and physical activity

The Madrid quantum network: a quantum-classical integrated infrastructure

We report on the Madrid Quantum Network, designed to demonstrate that a telecommunications network can also host quantum communications in a unified, logical and physical infrastructure. Using new Quantum Key Distribution systems paired with modern networking paradigms, we demonstrate a high technology readiness level of QKD installing the network in production facilities and running relevant use cases