From unprovability to environmentally friendly protocols

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

6 Scopus citations

Abstract

An important security concern for cryptographic protocols is the extent to which they adversely affect the security of the systems in which they run. In particular, can we rule out the possibility that introducing a new protocol to a system might, as a "side effect", break the security of unsuspecting protocols in that system? Universally Composable (UC) security rules out such adverse side effects. However, many functionalities of interest provably cannot be realized with UC security unless the protocol participants are willing to put some trust in external computational entities. We propose a notion of security that: (a) allows realizing practically any functionality by protocols in the plain model without putting trust in any external entity; (b) guarantees that secure protocols according to this notion have no adverse side-effects on existing protocols in the system - As long as the security of these existing protocols is proven via the traditional methodology of black box reduction to a game-based cryptographic hardness assumption with bounded number of rounds. Our security notion builds on the angel-based security notion of Prabhakaran and Sahai. A key part in our analysis is to come up with a CCA-secure commitment scheme that (a) cannot be proven secure via a black box reduction to a game-based assumption, but (b) can be proven secure using a non-black-box reduction. To the best of our knowledge, this is the first time that the interplay between black-box provability and unprovability is used to demonstrate security properties of protocols.

Original languageEnglish
Title of host publicationProceedings - 2013 IEEE 54th Annual Symposium on Foundations of Computer Science, FOCS 2013
Pages70-79
Number of pages10
DOIs
StatePublished - 2013
Event2013 IEEE 54th Annual Symposium on Foundations of Computer Science, FOCS 2013 - Berkeley, CA, United States
Duration: 27 Oct 201329 Oct 2013

Publication series

NameProceedings - Annual IEEE Symposium on Foundations of Computer Science, FOCS
ISSN (Print)0272-5428

Conference

Conference2013 IEEE 54th Annual Symposium on Foundations of Computer Science, FOCS 2013
Country/TerritoryUnited States
CityBerkeley, CA
Period27/10/1329/10/13

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