Efficient Cryptography for the Next Generation Secure Cloud

Add to your list(s) Download to your calendar using vCal

• Alptekin Küpçü, Koç University
• Tuesday 17 April 2012, 16:00-17:00
• Primrose Room, Microsoft Research Ltd, 7 J J Thomson Avenue (Off Madingley Road), Cambridge.

If you have a question about this talk, please contact Microsoft Research Cambridge Talks Admins.

This event may be recorded and made available internally or externally via http://research.microsoft.com. Microsoft will own the copyright of any recordings made. If you do not wish to have your image/voice recorded please consider this before attending

Peer-to-peer (P2P) systems, and client-server type storage and computation outsourcing constitute some of the major applications that the next generation cloud schemes will address. Since these applications are just emerging, it is the perfect time to design them with security and privacy in mind. Furthermore, considering the high-churn characteristics of such systems, the cryptographic protocols employed must be efficient and scalable.

In this talk, I will focus on an efficient and scalable fair exchange protocol that can be used for exchanging files between participants of a P2P file sharing system. It has been shown that fair exchange cannot be done without a trusted third party (called the Arbiter). Yet, even with a trusted Arbiter, it is still non-trivial to come up with an efficient solution, especially one that can be used in a P2P file sharing system with a high volume of data exchanged. Our protocol is optimistic, removing the need for the Arbiter’s involvement unless a dispute occurs. While the previous solutions employ costly cryptographic primitives for every file or block exchanged, our protocol employs them only once per peer, therefore achieving O(n) efficiency improvement when n blocks are exchanged between two peers. In practice, this corresponds to one-two orders of magnitude improvement in terms of both computation and communication (42 minutes vs. 40 seconds, 225 MB vs. 1.8 MB). Thus, for the first time, a provably secure (and privacy respecting when payments are made using e-cash) fair exchange protocol is being used in real bartering applications (e.g., BitTorrent) without sacrificing performance.

Finally, if time permits, I will briefly mention some of our other results on cloud security including ways to securely outsource computation and storage to untrusted entities, official arbitration in the cloud, impossibility results on distributing the Arbiter, keeping the user passwords safe, and the Brownie Cashlib cryptographic library including ZKPDL zero-knowledge proof description language we have developed. I will also be available to talk on these other projects after the presentation.

This talk is part of the Microsoft Research Cambridge, public talks series.

This talk is included in these lists:

• All Talks (aka the CURE list)
• Cambridge Centre for Data-Driven Discovery (C2D3)
• Cambridge talks
• Chris Davis' list
• Computer Laboratory Security Seminar
• Department of Computer Science and Technology talks and seminars
• Guy Emerson's list
• Interested Talks
• Microsoft Research Cambridge, public talks
• Optics for the Cloud
• PMRFPS's
• Primrose Room, Microsoft Research Ltd, 7 J J Thomson Avenue (Off Madingley Road), Cambridge
• School of Technology
• Security-related talks
• Trust & Technology Initiative - interesting events
• bld31
• ndk22's list
• ob366-ai4er
• personal list
• rp587

Note that ex-directory lists are not shown.