Paper 2021/174
Smart Contracts for Incentivized Outsourcing of Computation
Alptekin Küpçü and Reihaneh Safavi-Naini
Abstract
Outsourcing computation allows a resource limited client to expand its computational capabilities by outsourcing computation to other nodes or clouds. A basic requirement of outsourcing is providing assurance that the computation result is correct. We consider a smart contract based outsourcing system that achieves assurance by replicating the computation on two servers and accepts the computation result if the two responses match. Correct computation result is obtained by using incentivization to instigate correct behaviour in servers. We show that all previous replication based incentivized outsourcing protocols with proven correctness, fail when automated by a smart contract because of the copy attack where a contractor simply copies the submitted response of the other contractor. We then design an incentivization mechanism that uses two lightweight challenge-response protocols that are used when the submitted results are compared, and employs monetary rewards, fines, and bounties to incentivize correct computation. We use game theory to model and analyze our mechanism, and prove that with appropriate choices of the mechanism parameters, there is a single Nash equilibrium corresponding to the contractors’ strategy of correctly computing the result. Our work provides a foundation for replicated incentivized computation in the smart contract setting and opens new research directions.
Metadata
- Available format(s)
-
PDF
- Category
- Applications
- Publication info
- Preprint. MINOR revision.
- Keywords
- smart contractoutsourced computationincentivized computationgame theorymechanism designverifiable computation
- Contact author(s)
- kupcu @ acm org
- History
- 2021-03-26: revised
- 2021-02-20: received
- See all versions
- Short URL
- https://ia.cr/2021/174
- License
-
CC BY
BibTeX
@misc{cryptoeprint:2021/174, author = {Alptekin Küpçü and Reihaneh Safavi-Naini}, title = {Smart Contracts for Incentivized Outsourcing of Computation}, howpublished = {Cryptology {ePrint} Archive, Paper 2021/174}, year = {2021}, url = {https://eprint.iacr.org/2021/174} }