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AStERISK: Auction-based Shared
Economy ResolutIon System for
blocKchain
Alberto Sonnino, Michał Król, Argyrios Tasiopoulos, Ioannis Psaras
University College London
Cloud Computing
Cloud Computing
privacyissues
SPOF positionabuse
Cloud Computing Sharing Economy
privacyissues
SPOF positionabuse
Cloud Computing Sharing Economy
privacyissues
SPOF positionabuse
computation storage content
6
Assignment problem
7requesters
Assignment problem
8requesters workers
Assignment problem
9requesters workers
Assignment problem
10requesters workers
Assignment problem
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user worker
performs work for users
Optimal price determination
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user worker
performs work for users
I want to pay as little as possible
Optimal price determination
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user worker
performs work for users
I want to pay as little as possible
I want to get as much as possible
Optimal price determination
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user worker
performs work for users
I want to pay as little as possible
I want to get as much as possible
Why not run a distributed auction?!
Optimal price determination
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Auctions on Blockchain
● Inherit security guarantees from the underlying blockchain
● No single 3rd trusted party● Data submitted to the blockchain
automatically becomes public
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Bids privacy
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Bids privacy
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Bids privacy
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Bids privacy
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Bids privacy
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Bidders privacy
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Bidders privacy
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Bidders privacy
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Asterisk
● Auction-based shared economy resolution system running on top of blockchain
● Hides submitted bids/minimum price and protects bidders identity
● Does not rely on a single trusted 3rd party● Allows workers to automatically claim
money upon submission of a proof of useful work
● Designed for Filecoin, but can be used with other systems
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Anonymous Credentials
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Anonymous Credentials
ISSUE CREDENTIALS
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Anonymous Credentials
ISSUE CREDENTIALS
Name Age Authorized
John 32 Yes
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Anonymous Credentials
ISSUE CREDENTIALS
Name Age Authorized
John 32 Yes
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Anonymous Credentials
ISSUE CREDENTIALS
Name Age Authorized
John 32 Yes
Age > 18
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Anonymous Credentials
ISSUE CREDENTIALS
Name Age Authorized
John 32 Yes
Age > 18 Authorized == yes
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Anonymous Credentials
ISSUE CREDENTIALS
Name Age Authorized
John 32 Yes
Age > 18 Authorized == yes
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Anonymous Credentials
ISSUE CREDENTIALS
Name Age Authorized
John 32 Yes
Age > 18 Authorized == yes
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Coconut
● Credentials issued by multiple authorities
● Authenticity and availability even when a subset of authorities are malicious or offline
● Colluding authorities cannot break unlinkability and de-anonymize users
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Preparation phase
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Preparation phase
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Preparation phase
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Preparation phase
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Preparation phase
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Auction phase
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Auction phase
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Auction phase
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Auction phase
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Auction phase
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Execution phase
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Execution phase
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Execution phase
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Execution phase
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Performance
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Related Work
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Limitations
● Does not scale well with a large number of users
● The winner of the auction may refuse to transfer data to the worker preventing the worker from claiming the reward
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Future work
● Prototype with off-chain computations and on-chain verification
● Support for different auction types
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Questions?
