Paper 2005/163

Modeling Insider Attacks on Group Key-Exchange Protocols

Jonathan Katz and Ji Sun Shin

Abstract

Protocols for authenticated key exchange (AKE) allow parties within an insecure network to establish a common session key which can then be used to secure their future communication. It is fair to say that group AKE is currently less well understood than the case of two-party AKE; in particular, attacks by malicious insiders --- a concern specific to the group setting --- have so far been considered only in a relatively ``ad-hoc'' fashion. The main contribution of this work is to address this deficiency by providing a formal, comprehensive model and definition of security for group AKE which automatically encompasses insider attacks. We do so by defining an appropriate ideal functionality for group AKE within the universal composability (UC) framework. As a side benefit, any protocol secure with respect to our definition is secure even when run concurrently with other protocols, and the key generated by any such protocol may be used securely in any subsequent application. In addition to proposing this definition, we show that the resulting notion of security is strictly stronger than the one proposed by Bresson, et al. (termed ``AKE-security''), and that our definition implies all previously-suggested notions of security against insider attacks. We also show a simple technique for converting any AKE-secure protocol into one secure with respect to our definition.

Note: Typos in the definitions corrected.

Metadata
Available format(s)
PDF
Category
Cryptographic protocols
Publication info
Published elsewhere. An extended abstract will appear at ACM CCCS '05
Keywords
key exchange
Contact author(s)
jkatz @ cs umd edu
History
2008-06-17: last of 2 revisions
2005-06-06: received
See all versions
Short URL
https://ia.cr/2005/163
License
Creative Commons Attribution
CC BY

BibTeX

@misc{cryptoeprint:2005/163,
      author = {Jonathan Katz and Ji Sun Shin},
      title = {Modeling Insider Attacks on Group Key-Exchange Protocols},
      howpublished = {Cryptology {ePrint} Archive, Paper 2005/163},
      year = {2005},
      url = {https://eprint.iacr.org/2005/163}
}
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