Paper 2009/039

Key Insulation and Intrusion Resilience Over a Public Channel

Mihir Bellare, Shanshan Duan, and Adriana Palacio


Key insulation (KI) and Intrusion resilience (IR) are methods to protect a user's key against exposure by utilizing periodic communications with an auxiliary helper. But existing work assumes a secure channel between user and helper. If we want to realize KI or IR in practice we must realize this secure channel. This paper looks at the question of how to do this when the communication is over what we are more likely to have in practice, namely a public channel such as the Internet or a wireless network. We explain why this problem is not trivial, introduce models and definitions that capture the desired security in a public channel setting, and provide a complete (and surprising) answer to the question of when KI and IR are possible over a public channel. The information we provide is important to guide practitioners with regard to the usage of KI and IR and also to guide future research in this area.

Available format(s)
Cryptographic protocols
Publication info
Published elsewhere. A preliminary version of this paper appears in the proceedings of CT-RSA 2009.
Contact author(s)
shduan @ cs ucsd edu
2009-01-25: received
Short URL
Creative Commons Attribution


      author = {Mihir Bellare and Shanshan Duan and Adriana Palacio},
      title = {Key Insulation and Intrusion Resilience Over a Public Channel},
      howpublished = {Cryptology ePrint Archive, Paper 2009/039},
      year = {2009},
      note = {\url{}},
      url = {}
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