On the positive side, we show that if adversaries do not share any entangled quantum state but can compute arbitrary quantum operations, secure position-verification is achievable. Jointly, these results suggest the interesting question whether secure position-verification is possible in case of a bounded amount of entanglement. Our positive result can be interpreted as resolving this question in the simplest case, where the bound is set to zero. In models where secure positioning is achievable, it has a number of interesting applications. For example, it enables secure communication over an insecure channel without having any pre-shared key, with the guarantee that only a party at a specific location can learn the content of the conversation. More generally, we show that in settings where secure position-verification is achievable, other position-based cryptographic schemes are possible as well, such as secure position-based authentication and position-based key agreement.
Category / Keywords: foundations / Position based cryptography Date: received 11 May 2010, last revised 12 Dec 2010 Contact author: gelles at cs ucla edu Available format(s): PDF | BibTeX Citation Version: 20101212:193004 (All versions of this report) Short URL: ia.cr/2010/275 Discussion forum: Show discussion | Start new discussion