Oracles Thus Far Bitcoin Ethereum Recap Bitcoin Script: Dest - - PowerPoint PPT Presentation

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Oracles Thus Far Bitcoin Ethereum Recap Bitcoin Script: Dest - - PowerPoint PPT Presentation

Oracles Thus Far Bitcoin Ethereum Recap Bitcoin Script: Dest Address in UTXO Timelock What else? Recap Ethereum Smart contracts Examples? Real-World When the temperature hits XF, pay $. When player X


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SLIDE 1

Oracles

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SLIDE 2

Thus Far

  • Bitcoin
  • Ethereum
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SLIDE 3

Recap

  • Bitcoin Script:
  • Dest Address in UTXO
  • Timelock
  • What else?
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SLIDE 4

Recap

  • Ethereum
  • Smart contracts
  • Examples?
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SLIDE 5

Real-World

  • When the temperature hits X°F, pay $.
  • When player X scores a home run, pay $.
  • When Stock price hits 14, sell/buy.
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SLIDE 6

In Our Setup

  • Impossible
  • Can only reference on-chain information
  • Who puts this on chain?
  • What does the protocol need to allow?
  • What if you cheat?
  • Today’s Topic
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SLIDE 7

Types

  • What types of information do we reference?
  • What types of trust / faith do we require?
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SLIDE 8

Types

  • Booleans:
  • stock_price > 30
  • temperature > 20°
  • Time Series:
  • [s1, s2, …, sn]
  • URLs
  • Complex Schema
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SLIDE 9

Real World

  • Sports
  • Gamble on next pitch
  • TV / Radio
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SLIDE 10

Real World

  • Authoritative source
  • News org
  • TV
  • Radio
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SLIDE 11

Real World

  • Sensor network (IoT)
  • Readings on blockchain
  • Trust?
  • Know their addresses a-priori
  • Stolen identity?
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SLIDE 12

Real World

  • I pay you when HTTP request returns response X
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SLIDE 13

Real-World

  • On receiving payment of 1 BTC, unlock next level on video

game.

  • Outbound
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SLIDE 14

Storage?

  • Where do you put this data?
  • Ethereum?
  • Bitcoin?
  • Expensive!
  • Miners need to store the full chain
  • Cannot possibly service all the data-storage needs
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SLIDE 15

Problem Dimensions

  • Schema
  • Inbound / Outbound
  • Storage
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SLIDE 16

Any Ideas?

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SLIDE 17

Attempts

  • Truthcoin
  • Bitcoin Sidechain
  • Prediction Market
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SLIDE 18

Truthcoin

  • PoW Blockchain
  • 2 Types of Coin:
  • CashCoin
  • VoteCoin
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SLIDE 19

Truthcoin

  • CashCoin:
  • 1:1 redeemable for BTC
  • Use to create a prediction market (PM)
  • Buy/Sell PM shares
  • VoteCoin:
  • Equity in “oracle corporation”
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SLIDE 20

Truthcoin

  • VoteCoin:
  • Corresponds to voting influence
  • Not really a store of value (or at least worse than CashCoin)
  • Rules to own them
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SLIDE 21

VoteCoin

  • If you own VoteCoin:
  • You must vote Y/N/Unk
  • On “Decisions”
  • Incentive mechanisms
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SLIDE 22

VoteCoin

  • Lost if you don’t vote
  • Lost if you vote against majority
  • Gained if you tiebreak, pay attention to neglected decisions
  • Incentive Model
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SLIDE 23

Core Idea

  • Create a market
  • Ask for votes on “Decisions”
  • Oracle
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SLIDE 24

Voters

  • Incentivized to:
  • Vote with the rest (reality)
  • Vote on all decisions
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SLIDE 25

VoteCoin

  • Coin values = Reputatin
  • Fixed # of coins - just exchanged based on voting activity
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SLIDE 26

Issues?

  • Can answer “some” kinds of questions:
  • POTUS on 11/08/2019?
  • Who will win the Superbowl 2020?
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SLIDE 27

Issues?

  • What do this sensor network say?
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SLIDE 28

VoteCoin

  • Sell your account (reputation) to someone?
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SLIDE 29

Issues?

  • Everyone *has* to vote.
  • Additional “carrots” + “sticks” to make these prediction markets

work.

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SLIDE 30

Augur

  • Similar incentive models
  • Incentive to vote
  • Penalty for abstaining
  • Reputation model
  • Ethereum Dapp
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SLIDE 31

Augur

  • Final truth arbiter appointed at time of Q creation
  • After event, arbiter has some time period to post result
  • Can dispute this result
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SLIDE 32

Those Were

  • Consensus based
  • Voting
  • Limited to certain types of facts
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SLIDE 33

Sensors/IoT

  • Hardware oracles
  • Cryptographic attestation of data
  • Make sure tampering is identifiable so you can reject data
  • Harder said than done
  • Implications:
  • Insurance fraud
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SLIDE 34

Centralized

  • What if I just trust authority figures?
  • Centralized oracle
  • One authoritative source of facts
  • Trust it in your smart contracts
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SLIDE 35

Centralized

  • Is the platform still decentralized?
  • If data providers are centralized?
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SLIDE 36

ChainLink

  • Decentralized
  • But different
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SLIDE 37

Compared to Augur

  • Decentralized in market creation time.
  • Networks achieves consensus on truth source
  • Truth source then delivers truth
  • Dispute / Accept
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SLIDE 38

Compared to Augur

  • Here, multiple sources of truth
  • These sources then achieve consensus
  • How?
  • At contract level
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SLIDE 39

Chainlink

  • Contract:
  • Reputation
  • Oracle performance tracking
  • Order-match
  • Collect bids from oracle providers
  • Aggregation
  • Aggregate results from oracle and produce final result
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SLIDE 40

Chainlink

  • Primitives for aggregation
  • Schema dependent
  • Some provided in chainlink
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SLIDE 41

Chainlink

  • Freeloading?
  • Lazy oracle just copies and sends response
  • Solution:
  • Commit and reveal
  • Cryptographic commitment
  • Reveal responses
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SLIDE 42

Chainlink

  • Aggregate off-chain
  • Storage issues
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SLIDE 43

Chainlink Reputation

  • Publish user ratings of oracles
  • Payment in LINK tokens
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SLIDE 44

Outbound?

  • Inform sidechains
  • Smart contract on chain 1 -> unlock payment on chain 2
  • Inform outside world
  • Comes with own trust model
  • Do you trust the external aggregator?
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SLIDE 45

Questions