IACR News item: 25 October 2011
PhD Database
Name: Nishanth Chandran
Topic: Theoretical Foundations of Position-Based Cryptography
Category: cryptographic protocols
Description: In this thesis, we initiate the study of cryptographic protocols where the identity, or other credentials and inputs, of a party are derived from its \\emph{geographic location}.\r\n\r\nWe start by considering the central task in this setting, i.e., securely verifying the position of a device. Despite much work in\r\nthis area, we show that in the Vanilla (or standard) model, this above task (i.e., of secure positioning) is impossible to achieve,\r\neven if we assume that the adversary is computationally bounded. In light of the above impossibility result, we then turn to\r\nDziembowski\'s Bounded Retrieval Model (a variant of Maurer\'s Bounded Storage Model) and formalize and construct information theoretically secure protocols for two fundamental tasks:\r\n\r\n\\begin{itemize}\r\n\\item[-]\r\nSecure Positioning; and\r\n\\item[-]\r\nPosition-Based Key Exchange.\r\n\\end{itemize}\r\n\r\nWe then show that these tasks are in fact {\\em universal\\/} in this setting -- we show how we can use them to realize Secure Multi-Party Computation.\r\n\r\nThe main contribution of this thesis is threefold: to place the problem of secure positioning on a sound theoretical footing; to\r\nprove a strong impossibility result that simultaneously shows the insecurity of previous attempts at the problem; and to present positive results showing that the bounded-retrieval framework is a fruitful one to study the foundations of position-based\r\ncryptography.\r\n\r\nThis thesis is based on joint works with Vipul Goyal, Ryan Moriarty, and Rafail Ostrovsky.[...]
Topic: Theoretical Foundations of Position-Based Cryptography
Category: cryptographic protocols
Description: In this thesis, we initiate the study of cryptographic protocols where the identity, or other credentials and inputs, of a party are derived from its \\emph{geographic location}.\r\n\r\nWe start by considering the central task in this setting, i.e., securely verifying the position of a device. Despite much work in\r\nthis area, we show that in the Vanilla (or standard) model, this above task (i.e., of secure positioning) is impossible to achieve,\r\neven if we assume that the adversary is computationally bounded. In light of the above impossibility result, we then turn to\r\nDziembowski\'s Bounded Retrieval Model (a variant of Maurer\'s Bounded Storage Model) and formalize and construct information theoretically secure protocols for two fundamental tasks:\r\n\r\n\\begin{itemize}\r\n\\item[-]\r\nSecure Positioning; and\r\n\\item[-]\r\nPosition-Based Key Exchange.\r\n\\end{itemize}\r\n\r\nWe then show that these tasks are in fact {\\em universal\\/} in this setting -- we show how we can use them to realize Secure Multi-Party Computation.\r\n\r\nThe main contribution of this thesis is threefold: to place the problem of secure positioning on a sound theoretical footing; to\r\nprove a strong impossibility result that simultaneously shows the insecurity of previous attempts at the problem; and to present positive results showing that the bounded-retrieval framework is a fruitful one to study the foundations of position-based\r\ncryptography.\r\n\r\nThis thesis is based on joint works with Vipul Goyal, Ryan Moriarty, and Rafail Ostrovsky.[...]
Additional news items may be found on the IACR news page.