Research Progress Update
Blockchain Technology Lab
Orfeas Stefanos Thyfronitis Litos
Motivating problem: user perspective
Trusting a vendor
- Question: "I found an online store that seems great and cheaper than ebay. Should I buy from there?"
- Simple answer: "Ask your friends"
Motivating problem: researcher perspective
- What does "trust" even mean?
- How to formally argue about trust?
- Is there a way to reliably measure trust without assuming Trusted Third Parties?
- Today's assumption: ebay is trustworthy
- Aim: no assumptions, just an amazing reputation system (or why it's impossible)
- Model a simple market
- Model a generic mechanism for answering questions like "which vendor is more trustworthy?"
- Compare the various mechanisms
- Show whether a foolproof reputation system without Trusted Third Parties is feasible
- Alice has a desire.
- Bob can satisfy it for a price
- But he can take the money and run.
- So, before paying him, Alice asks the Trust functionality.
- If it says OK, Alice goes on to Trade with Bob.
- Question: What is the best (implementable) Trust functionality?
Blockchains don't scale
- Consensus: everybody agrees on what happened
Present: every computer learns every transaction
- Will never scale well
Payment channels to the rescue!
- As long as interested parties agree, the world doesn't have to know
- If parties disagree, the world is the arbiter
Literature is already big:
- Lightning (Bitcoin)
- Perun (Ethereum)
- Bolt (Zcash)
- TeeChan (Intel TEE)
Inverting the question
- What is the minimal global ledger needed for robust payment channels?
- Does it have to be a blockchain?
- Is Ripple/Stellar the answer, or can we do better?
- No answers yet, exploring how trust could be leveraged
What if not a blockchain?
- The global ledger consists of trust relationships
- In case of dispute, trust is rearranged
- On expectation only the cheater loses money
Trust models and semantics
- Simple market model
- Ideal Trust functionality
- Is it realizable?
Payment channels (i.e. scaling)
- Desired properties of payment channels
- Global ledger designed just for payment channels
- Could Trust be leveraged?
15-16/2/2018 Progress Update