Using quantum key distribution for cryptographic purposes: A survey

Document history: During the first year of the SECOQC project [1], Philippe Grangier initiated an internal debate regarding the " comparative advantages " of quantum key distribution (QKD). A first written contribution to this debate, by Philippe Grangier, Louis Salvail, Nicolas Gisin and Thierry Debuisschert [2], was then made available to all SECOQC partners. In their 3rd review report, issued on June 26 2006, SECOQC project reviewers and scientific officer pointed out at the need of a paper about the " added value of QKD to classical cryptography ". Following this recommandation and extending on the arguments developped in [2], Romain Alléaume wrote a draft document, entitled QKD and Cryptography: strong points, weaknesses and comparative advantages. On October 12, at the London 10th SECOQC Core Group, project partners agreed to jointly contribute to the improvement of this draft document and make it evolve into the SECOQC cryptography white paper. Numerous comments, suggestions of corrections and new ideas were proposed through the SECOQC Wiki [3]. Based on those reactions, the first draft version of the paper has been modified and updated by Romain Alléaume, leading successively to the versions 2.0, 3.0, and 4.0. On November 21, version 4.0 of the white paper was presented at the Crypto networking session organized by the European Network of Excellence ECRYPT, at the Helsinki IST event. Preprints of the white paper have also been distributed. Final rounds of revisions, taking into account the comments received after the Helsinki event, have then lead to the current version, 5.1, of the white paper.