Nippon Telegraph and Telephone Corporation (Kiyoshi Tamaki)
Mitsubishi Electric Corporation
Hokkaido University
Nagoya University
Tokyo Institute of Technology
It is well known that the security of QKD is guaranteed under the assumptions of the mathematical models of users’ devices. However, it is also well recognized that there exists a gap between the mathematical assumptions and the actual operations of the devices in the real world. Another issue of the current theory is the security evaluation with finite data size. In most of the security proofs, the security is guaranteed only assuming infinitely large data length whereas in the real QKD system the data size is obviously finite. The mission of our team is to fill this gap basically from a theoretical side. Our project consists of the following subthemes:
Interim results for Team 157BT01
Task title  Outcome  Date  Note 

1: Security analysis for finitesize data  a) New theory for the finitelength security analysis of BB84 with a single photon source allowing the improvement of the key generation rate.Fig. 1a  Sep. 2012  New J. Phys. 14, 093014 (2012) 
b) New theory for the finitelength security analysis of the decoy methodFig. 1b  Jun. 2013  QIP2013, TQC2012.  
2: Development on efficient postprocessing, PA, and ECFig. 2a  a) New class of hash functions formulated  Sep. 2012  IEEE Trans. Info. Theory, 59, 4700 (2013) 
b) Fast encoding algorithm for spatiallycoupled LDPC codes developed  Jul. 2013  IEEE ITW2012 (Invited poster)  
c) Implementation of the fast parallel errorcorrection decoding algorithm on GPGPU  Jul. 2013  Installed on the CV QKD system developed in team 157CT01  
d) Fast and exact numerical computation algorithm for interval estimation of phase error rate (the singlephoton BB84 key rate improved)  Aug. 2013  QCrypt2013  
3: Device characterization and the security patch against sidechannel attacks  a) New detector sidechannel attack free (measurement device independent: MDI) QKD protocol proposedFig. 3a  Mar. 2012 

b) Novel optical circuits against the sidechannel attack on phase modulators proposedFig. 3b  May 2012  Patent applied  
c) Phase correlation measurement for gainswitched laser pulses up to 1GHzFig. 3c  Mar. 2013  QCrypt2013  
d) Novel optical circuits compensating the detection efficiency mismatch proposed  Sep. 2013  Patent applied  
4: Security proofs for various protocols  a) New security analysis of B92 resulting improved asymptotic key rates  Jul. 2013  IEEE ISIT2013 
b) Security proof of CV QKD against calibration attacks on local oscillators  Aug. 2013  QCrypt2013  
c) Proof of unconditional security of the DPS QKD with blockwise phase randomization  Aug. 2013  QCrypt2013 
Targets for Team 157BT01
Task title  Work/Milestone  Due Date  Note 

5: System monitoring  
6: Random number generator  Proofofprinciple experiment  Mar. 2014  
Prototype development  Mar. 2016  
7: Efficient key distillation algorithm for CVQKD  Design and implementation an efficient key distillation software for a CVQKD system. (with Gakushuin Univ. and TITECH)  
Offline demonstration  Oct. 2013  
8: Document for security certificate  To write a document for security certificate of QKD  Mar. 2016 
Chart 1Schedule for Team 157BT01