AStERISK: Auction-based Shared Economy ResolutIon ... - ndss-symposium…€¦ · Cloud Computing...

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?