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SUMMARY:Betrayal\, Distrust\, and Rationality: Smart Counter-Collusion Con
 tracts for Verifiable Cloud Computing - Changyu Dong\, School of Computing
 \, Newcastle University
DTSTART:20171017T130000Z
DTEND:20171017T140000Z
UID:TALK80621@talks.cam.ac.uk
CONTACT:Alexander Vetterl
DESCRIPTION:Cloud computing has become an irreversible trend. There is a p
 ressing need for verifiability: the cloud providers are external parties w
 hose interests may not fully align with those of its clients\, therefore t
 hey cannot be fully trusted. To exercise due diligence and gain greater co
 nfidence in computation outsourced to the cloud\, clients need to be able 
 to verify the correctness of the results returned. However\, existing veri
 fiable computation techniques all have a high overhead\, thus if being dep
 loyed in the clouds\, would render cloud computing more expensive than the
  on-premises counterpart\, and would diminish the motivation for using the
  clouds.\n\nIn this talk\, I will present our recent attempt to achieve ve
 rifiability at a reasonable cost\, by leveraging game theory and smart con
 tracts\, which is a newly developed paradigm on top of the blockchain tech
 nology. In a nutshell\, a client lets two clouds compute the same task\, a
 nd uses smart contracts to stimulate tension\, betrayal and distrust betwe
 en the clouds\, so that rational clouds will not collude and cheat. In the
  absence of collusion\, verification of correctness can be done easily by 
 crosschecking the results from the two clouds. We provide a formal analysi
 s of the games induced by the contracts\, and prove that the contracts wil
 l be effective under certain reasonable assumptions. By resorting to game 
 theory and smart contracts\, we are able to avoid heavy cryptographic prot
 ocols. The client only needs to pay two clouds to compute in the clear\, a
 nd a small transaction fee to use the smart contracts. We also conducted a
  feasibility study that involves implementing the contracts in Solidity an
 d running them on the official Ethereum network.  \n\nThe talk is based on
  a recent paper in CCS 2017\, the full version of the paper can be accesse
 d through https://arxiv.org/abs/1708.01171.\n
LOCATION:LT2\, Computer Laboratory\, William Gates Building
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