OpenBazaar

OpenBazaar

Building a decentralized marketplace network

OpenBazaar

What is OpenBazaar?

• Decentralized marketplace for conducting censorship resistant, private trade online

• It’s like eBay and BitTorrent had a baby

OpenBazaar

Primary Team Members• Brian Hoffman (Project Lead):

Serves as core developer and run day to day operations for the project including architecture, design, marketing and infrastructure

• Sam Patterson (Operations):Manages marketing and fundraising, software testing and provides other various project support

• Dr. Washington Sanchez (Research):Conducts research and development in OpenBazaar smart contracts, arbitration, reputation and trust

• Dionysis Zindros (Research/Development):Researching identity, trust and reputation in anonymous peer to peer networks

• Jonas Nick (Developer):Python and ZeroMQ expert and one of the core developers for the project.

• Many others…

OpenBazaar

History of OpenBazaar

• Dark Market was the winning hackathon entry at the Bitcoin Expo in Toronto winning $20,000

• Proof of concept source code was released by Airbitz and unSYSTEM

• Forked from Dark Market on April 24

• Created an official GitHub organization and spun off as OpenBazaar amid name distraction (see Reddit)

Dark Market is a scary name

OpenBazaar

Why should you care?

• Happiness– Most online shopping experiences suck

• Freedom– Buy what you want from whom you want

• Wealth– Being a merchant online costs money

• Seller fees (ebay: 10% of total + shipping + PayPal fees)

• Credit Card processing• Listing “upgrades”

– Less fees == More Profit and Deeper Discounts

OpenBazaar

How does it work?• Everyone is a node in the p2p network• Everyone is a merchant, buyer and/or

arbiter• Bitcoin is used as the currency (for now)• Merchants create listings/contracts and

publish them to the network• Buyers find listings and enter into

agreements with a merchant and an arbiter

• Once goods are shipped or services rendered, 2-of-3 parties sign and release the funds

• Users can rate each other to create reputation

• Arbiters receive fees for dispute resolution

OpenBazaar

Peer to Peer Network• Kademlia-like system• Peers communicate via encrypted messages passed

between ZeroMQ servers• Not a flooding network like Bitcoin• Not all nodes need to store all information• Looking into D1HT to reduce hops for finding keys/nodes• Distributed Hash Table (DHT)

– Listings/Contracts can be persisted on the DHT for redundancy and to provide search when a node goes offline temporarily

– Store listing keys stored in a reverse index– Keyword searching for listings stored in reverse index; complex

queries supported but slower– Data is republished periodically to ensure freshness

OpenBazaar

Current GUI

OpenBazaar

Store Pages

OpenBazaar

Listings (Contracts)

• OpenBazaar can support many different types of listings through the use of Ricardian Contracts

• Ricardian Contracts are digital documents, parsable by computers and humans, that defines a type of value that can be issued over the Internet[1]

• Allow buyers to create and agree to contracts offline

• JSON structure• Some uses: fixed price sales, auctions, p2p

lending, share issuance[1] Paraphrased from http://iang.org/papers/ricardian_contract.html

OpenBazaar

Ricardian Contracts

OpenBazaar

Contract Generator Tool

OpenBazaar

How do you buy a contract?1. Seller creates a contract and puts it out on the network2. Buyer digitally signs the contract and sends it back to the seller3. Seller agrees by signing the buyer’s version of the contract4. Arbiter agrees to mediate the transaction by signing the

contract and creating a multisig 2 of 3 address5. The arbiter transfers this signed contract and multisig address

to both the buyer and seller6. Buyer sends money to the multisig address and confirms

payment7. Seller acknowledges payment and ships goods or delivers

service8. Upon successful delivery buyer signs and sends a ‘closed’

contract to the seller9. Seller checks to make sure all is right and broadcasts the

multisig transaction to the Bitcoin network

OpenBazaar

You screwed me…now what?• Buyer/seller flags transaction for dispute• Arbiter is notified and participants provide evidence for

either side to the arbiter• Arbiter makes a judgment and creates a transaction to

reverse payment or signs original contract or whichever solution all parties decide on

• Arbiters– Fees for dispute resolution are paid to arbiters– Arbiters can command a high or low fee based on reputation and skill

set– Anyone can be an arbiter

• Voting Pools: Third-party arbiter could be a group of voters where the majority decides how to handle the dispute– Threshold Signatures: Group of people have private key and requires a

certain amount of individuals to participate to create a valid signature

OpenBazaar

Reputation & Identity• Identity

– GUIDs (Node ID) are derived from your public key– Nicknames (optional) within the network are tied to public keys– Used for authentication of messages across network– Proof of Burn: Classes of users to establish initial trust

• Web of Trust– Nodes rate other trusted nodes and begin to establish trust

webs– Popular marketplaces may create trust webs based on

favorability– Ratings: ratings affect reputation based on all activities within

the network (i.e. buying, selling, arbitrating)– Will allow us to segregate malicious nodes or groups who try to

create fake webs of trust

OpenBazaar

Anonymity

• Tor Proxy• I2P• Retroshare• Development Status:

– Currently we use ZeroMQ as our messaging infrastructure and there is no great way to use it with a SOCKS5 proxy

– libzmq team adding this soon and pyzmq (we use) is built against it so enabling this is coming

– Lots of great suggestions from the community for improving anonymity and our strategy is constantly evolving

OpenBazaar

Threat Model

• Too many threats to count?

• DHT– Sybil: Attacker creates

many nodes to forge reputation

– Spartacus: Attacker assumes the same GUID as another

– Eclipse Attack: poison the routing table

• Bitcoin• Web of Trust

OpenBazaar

Roadmap

• Q2 (Apr-Jun):– Ricardian Contracts– HTML Contract Generator– Alpha Release of Web Client– Collaboration Consolidation– Continued development

• Q3 (Jul-Sep):– Beta Release and Testing– Bug Fixes– Protocol Enhancements– Contract Enhancements

• Q4 (Oct-Dec):– Official Release v1.0

OpenBazaar

What’s in it for us?

• Why are we doing this?• AGPL License– Copyleft– Anything that uses the software over a network

has to contribute their modifications back to the community

– If you simply use the core code as is then you have no obligations; only if you modify it

• Community-driven not a corporation

OpenBazaar

How can you help?

• Time:– Forum Discussions (http://forum.openbazaar.org)– Coding (http://github.com/OpenBazaar/OpenBazaar)– IRC (#OpenBazaar on FreeNode)

• MoneyOur team requires minimal investment right now; an altruistic venture. However we can use funds for:– Marketing purposes (i.e. flyers, stickers, conferences)– Seed server hosting– Programmer bounties

OpenBazaar

Contact Us

• Come see us at our booth• http://www.openbazaar.org• project@openbazaar.org