匿名性は豊饒の土地

404 Blog Not Found:弱いんじゃない、力がないだけだ
こういう実世界での匿名性とは関係無く, 暗号業界的には匿名性が重要である. それが枕かよ. まぁ匿名通信が実装されているなら, その通信経路を利用して様々なアプリケーションが存在するという話があって面白い. B4のN君が印刷していて面白そうだったので紹介.
ePrint Archive 2006/084 Yuval Ishai, Eyal Kushilevitz, Rafail Ostrovsky and Amit Sahai "Cryptography from Anonymity"

  • Feasibility. We show that anonymous communication over insecure channels can be used to implement unconditionally secure point-to-point channels, broadcast, and general multi-party protocols that remain unconditionally secure as long as less than half of the players are actively corrupted.
  • Efficiency. We show that anonymous channels can yield major efficiency improvements for several natural secure computation tasks. In particular, we present the first solution to the problem of private information retrieval (PIR) which can handle multiple users while being close to optimal (in an amortized sense) with respect to both communication and computation.

匿名通信を利用して, secure channelが作れて, MPCが出来ると. PIRも作れてしまうと. 何でこうなるか全然直観が湧かなくって素敵.
1月後のゼミでやるのもありかも. Boaz Barak et.al. の"On the (Im)possibility of Obfuscating Programs"とどっちにしようか迷っている.