Position Based Cryptography
- Nishanth ChandranAffiliated withDepartment of Computer Science, UCLA
- , Vipul GoyalAffiliated withDepartment of Computer Science, UCLA
- , Ryan MoriartyAffiliated withDepartment of Computer Science, UCLA
- , Rafail OstrovskyAffiliated withDepartment of Computer Science and Mathematics, UCLA
We consider what constitutes identities in cryptography. Typical examples include your name and your social-security number, or your fingerprint/iris-scan, or your address, or your (non-revoked) public-key coming from some trusted public-key infrastructure. In many situations, however, where you are defines your identity. For example, we know the role of a bank-teller behind a bullet-proof bank window not because she shows us her credentials but by merely knowing her location. In this paper, we initiate the study of cryptographic protocols where the identity (or other credentials and inputs) of a party are derived from its geographic location.
Secure Positioning; and
Position Based Key Exchange.
We then show that these tasks are in fact universal in this setting – we show how we can use them to realize Secure Multi-Party Computation.Our main contribution in this paper is threefold: to place the problem of secure positioning on a sound theoretical footing; to prove a strong impossibility result that simultaneously shows the insecurity of previous attempts at the problem; and to present positive results by showing that the bounded-storage framework is, in fact, one of the “right” frameworks (there may be others) to study the foundations of position-based cryptography.
- Position Based Cryptography
- Book Title
- Advances in Cryptology - CRYPTO 2009
- Book Subtitle
- 29th Annual International Cryptology Conference, Santa Barbara, CA, USA, August 16-20, 2009. Proceedings
- pp 391-407
- Print ISBN
- Online ISBN
- Series Title
- Lecture Notes in Computer Science
- Series Volume
- Series ISSN
- Springer Berlin Heidelberg
- Copyright Holder
- Springer-Verlag Berlin Heidelberg
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