4. Marketplaces

Trade verticals in OpenBazaar refers to types of markets that can be built on top of the platform. In the theory section of the Github Readme, I have attempted to describe in minor detail how different types of markets can be built on the platform.

These include:

  1. E-Commerce
  2. Physical goods
    • Fixed price
    • Auctions
  3. Digital goods
  4. Services
  5. Service Contracts
  6. Invitation to Tender (ITT)
    • TradeNet
  7. Service Listing
  8. Good Performance Bonds
  9. Lending
    • P2P lending
    • Bonds
  10. Financial securities
    • Stocks
    • Futures (bounded futures)
    • Options
    • Swaps
  11. Decentralised Currency exchange
  12. Insurance
  13. Crowd funding
  14. Prediction markets

One question we are often asked is 'can OpenBazaar support X market?'... The answer is yes if the terms and conditions can be fully represented in a RC and Bitcoin is being used for the trade in exchange or to collateralise an exchange.

The challenge for market developers is to design RCs that capture the semantic detail of a trade to:

  1. Establish consensus between the trading parties
  2. Prevent all reasonable foreseeable disputes, based on hearsay
  3. Efficiently process on the OB network between the trading parties (i.e. an efficient signing order)

To incentivise good performance by each party, surety bonds can also be written into the contract. Surety bonds essentially reward or penalise a trading party based on performance criteria, which would be clearly stated within the RC.

4.1 E-Commerce

4.1 Physical Goods

Fixed Price Sales

Trade Flow

  1. Merchant creates and lists contract
  2. Listing includes notary guid and pubkeys (which the client can verify)
  3. Maybe if the verification fails (3 strikes rule or something) the buyer's node can prune the guid from nodes that they relay or connect to
  4. Includes processing time (maximum time the item must be shipped after receiving an order)
  5. Buyer places an order
  6. Appends network ID, pubkeys (PGP and bitcoin multisig escrow), semantic data unique to the item
  7. Appends shipping address (encrypted to merchant's public PGP key)
  8. Generates and appends 32 byte chaincode to create multisig address
  9. Appends txid of funding that multisig address
  10. Merchant ships item
  11. Includes tracking number
  12. Includes signed payout transaction releasing funds from multisig to merchant (i.e. 1 signatures of the 2-of-3 multisig)
  13. Buyer confirms item received
  14. Appends a message (if any) and rating/review data
  15. Signs and broadcasts payout transaction to merchant
  16. Appends txid of payout transaction

Example of listing contract

{
    "01_merchant": {
        "01_listing": {
            "01_metadata": {
                "01_obcv": "",
                "02_expiry": "",
                "03_category": "",
                "04_category_sub": "",
                "05_order_flow": [
                    "merchant",
                    "buyer",
                    "merchant",
                    "buyer"
                ]
            },
            "02_id": {
                "01_guid": "",
                "02_pubkeys": {
                    "bitcoin": "",
                    "pgp": ""
                },
                "03_handle": "",
                "04_passcard": "",
                "05_contact": {
                    "bitmessage": "",
                    "email": "",
                    "subspace": ""
                },
                "06_role": "merchant"
            },
            "03_item": {
                "01_title": "",
                "02_description": "",
                "03_condition": "",
                "04_price": {
                    "bitcoin": 0
                },
                "05_shipping": {
                    "est_delivery": "",
                    "region": ""
                },
                "06_images": {
                    "image_hashes": [
                        "",
                        "",
                        "",
                        "",
                        ""
                    ],
                    "image_urls": [
                        "",
                        "",
                        "",
                        "",
                        ""
                    ]
                },
                "07_keywords": [
                    "keyword1",
                    "keyword2"
                ]
            },
            "04_notary": {
                "01_guid": "",
                "02_pubkeys": {
                    "pgp": "",
                    "pubkey": "xxx",
                    "pubkey_selfsig": "XXX"
                },
                "03_handle": "",
                "04_passcard": ""
            }
        },
        "02_signatures": {
            "bitcoin": "",
            "pgp": ""
        }
    }
}

Auctions

It is becoming increasingly clear that OpenBazaar will become a powerful platform that will support a variety of peer-to-peer market transactions. One of the most fundamental market transaction types is the auction of a good by a seller to discover the market price. In this article, we cover one possible way of auctioning a good using Ricardian contracts.

It should be noted that this proposal essentially describes the 'back-end' of implementing Ricardian contracts into auctions on OpenBazaar. It is important that the end-user (i.e. your mother, grandfather etc with novice skills) will be unaware of digital signing, hashing etc occuring in the background unless they choose to be, in order to lower the technical barrier of entry for using OpenBazaar.

The merchant firstly selects an auction template contract in OpenBazaar. In this type of contract, the product and auction details of the good to be sold are entered into required fields within the JSON or XML file. The product auction details would include:

  1. The name and description of the item
  2. A minium sell price, if any
  3. A 'buy now' price, if desired
  4. An expiration date for the auction
  5. A blank field for a bidder to enter their price

For example, let's imagine Alice wants to sell a yellow pinata on OpenBazaar. After digitally signing it, the auction_contract looks something like this:

{
   "01" : {
      "01_listing" : {
         "01_metadata" : {
            "01_obcv" : "",
            "02_expiry" : "",
            "03_category" : "",
            "04_category_sub" : "",
            "05_order_flow" : [ "merchant", "buyer", "merchant", "buyer" ]
         },
         "02_id" : {
            "01_guid" : "",
            "02_pubkeys" : {
               "bitcoin" : "",
               "pgp" : ""
            },
            "03_handle" : "",
            "04_passcard" : "",
            "05_contact" : {
               "bitmessage" : "",
               "email" : "",
               "subspace" : ""
            },
            "06_role" : "merchant"
         },
         "03_item" : {
            "01_title" : "",
            "02_description" : "",
            "03_condition" : "",
            "04_price" : {
               "bitcoin" : 0.0
            },
            "05_shipping" : {
               "est_delivery" : "",
               "region" : ""
            },
            "06_images" : {
               "image_hashes" : [ "", "", "", "", "" ],
               "image_urls" : [ "", "", "", "", "" ]
            },
            "07_keywords" : [ "keyword1", "keyword2" ]
         },
         "04_notary" : {
            "01_guid" : "",
            "02_pubkeys" : {
               "pgp" : "",
               "pubkey" : "xxx",
               "pubkey_selfsig" : "XXX"
            },
            "03_handle" : "",
            "04_passcard" : ""
         }
      },
      "02_signatures" : {
         "bitcoin" : "",
         "pgp" : ""
      }
   }
}

Bob accesses the contract and chooses to bid on the pinata, appending his ID details and the bid price. Alice may receive five different bids on the yellow pinata and according to her conditions, the originally contract is updated with the latest bid price. At the end of the expiration date of the contract, Alice digitally signs the final winning bid contract, sends it to the arbiter for digitally signing and creating a multisignature bitcoin address for the winning bidder, Bob.

Due to the architecture of the P2P network setup, Alice may not be available 24/7 during the term of her auction contract to update the market on the latest bid price of the item. As a result, she may choose to upload her contract on a 24/7 accessible node (a negotiator node) that acts as a contract server. If so, the negotiator node will create their own contract for the item, digitally sign bid contracts, update the "current_bid", and turn over the final bid contract to Alice for her digital signature at the end of the contract/auction expiration date. If Alice digitally signs the contract, the contract is sent to an arbiter for sigining and creation of the multisignature bitcoin address for Bob, the winning bidder, to send funds to. As a reward for hosting the contract, the negotiator node is rewarded by a fee paid for by Alice (via another multisignature address setup with anoter arbiter). If Alice disapproves of how the contract was negotiated by the negotiator node on her behalf, she can simply refuse to sign the contract and raise a dispute to the arbiter for a refund of the fee from the multisignature address.

Insurance

For the seller (Alice), she can have confidence that the funds for the item actually exist once Bob has sent the required amount of bitcoins to the multisignature bitcoin address, upon which she will ship the item to Bob's designated address. Similarly for Bob, he can retrieve the funds from the multisignature address if he can prove to the arbiter's satisfaction that he goods either did not arrive, or did not arrive in the condition specified in the contract.

To further promote good behavior, the arbiter may require a surety bond from one or both parties. The surety bond is a quantity of bitcoins sent from either the buyer or seller (or both) held in a multisignature bitcoin address that is refundable upon a successful trade. If a dispute arises, and one party is found to be at malicious fault, the funds within the surety bond are transferred to the arbiter and opposing party as compensation.

A non-malicious versus malicous fault may be, for example, a shipping comapany damaging the goods during transport (non-malicious) versus the seller knowingly sending a damaged good (malicious). The value of the surety bond is negotiable and completely optional. However, it is reasonable to expect that surety bonds will become less necessary between individuals with a high web of trust reputation and/or proof of burn identity.

4.2 Services

Index:

  1. Service Contracts
  2. Invitation to Tender (ITT)
  3. Service Listing
  4. Good Performance Bonds

A service contract in OpenBazaar replaces a physical good to be sold with the terms and conditions of a service to be performed by one party. The distinction between a good and service within a Ricardian contract is minimal. Morever, the combination of reputation management and surety bonds can ensure a robust service industry within OpenBazaar.

Service Contracts

The final format of a service contract is of course comparable to that of a physical good. Similar to physical goods, there are several discovery mechanisms for services on OpenBazaar. For the sake of simplicity, we will examine two types of service contracts that can be supported in OpenBazaar, following the Ricardian contract model:

  1. Invitation to Tender (ITT)
  2. Service Listing

Invitation to Tender (ITT)

A call for bids, call for tenders, or invitation to tender (ITT) (often called tender for short) is a special procedure for generating competing offers from different bidders looking to obtain an award of business activity in works, supply, or service contracts... Open tenders, open calls for tenders, or advertised tenders are open to all vendors or contractors who can guarantee performance. (Wikipedia)

The first type of contract is an invitation to tender (ITT), whereby a client publishes their list of requirements for a desired good or service. In the context of a service, these details are specified within a Ricardian contract and distributed to potential service providers in the OpenBazaar network. Relevant ITT contract details include:

  1. Name and category of the service
  2. Chosen from a list of pre-determined categories and sub-cateogories
  3. This list will be frequently updated to reflect market needs, and include custom categories to support new markets on OpenBazaar
  4. Price range
  5. The price that the buyer is prepared to pay for the service
  6. This can be left blank
  7. Estimated time of completion
  8. The maximum time that a buyer expects the service to be performed
  9. Comments and special considerations
  10. Any comments or special details that the service provider needs to be aware of

The details of the contract can be further negotiated between the parties before a contract is double-signed (i.e. a contract signed by both the buyer and service provider indicating consensus on the final version of the contract)

For example, if Alice wanted to deliver some cupcakes to a co-worker on the other side of the city, she writes the following Ricardian-contract as an ITT:

Contract Hash: 5a13604e59b03c3b34f830c53919e176aa4cdc59

{
   "001" : {
      "listing" : {
         "id" : {
            "contact" : {
               "bitmessage" : "",
               "email" : "",
               "subspace" : ""
            },
            "guid" : "",
            "handle" : "",
            "onename" : "",
            "pubkeys" : {
               "bitcoin" : "xxx",
               "pgp" : "xxx"
            },
            "role" : "customer"
         },
         "metadata" : {
            "category" : "service",
            "category_sub" : "invitation to tender",
            "contract_code" : "123-xyz",
            "expiry" : "3 hours",
            "obcv" : "b5.0"
         },
         "order" : {
            "comments" : "Hi, I'd like to deliver the cupcakes to my co-worker before she gets into work, which is around 9.30 am. Thanks.",
            "date" : "2015-07-04 9 am ",
            "delivery_address" : "900 W Eddy St, Chicago, IL 60613, United States",
            "item" : "chocolate cupcake",
            "pickup_address" : "1060 W Addison St, Chicago, IL 60613, United States",
            "quantity" : 1,
            "type" : "delivery"
         }
      },
      "signatures" : {
         "bitcoin" : "XXX",
         "pgp" : "XXX"
      }
   }
}

Alice publishes the unencrypted contract to the OpenBazaar network, where service providers can scan for contracts that match the category/sub-category fields that they are interested in. Bob, owner of 'Raven Drone Courier', is interested in securing the contract. In order for a service provider to place a bid on a contract, they prepare a 'tender' that will append the following details to Alice's contract:

  1. ID details of the individual/business
  2. Fee for the service
  3. Terms and conditions for providing the service

The contract is then sent to Alice. Alice may receive tens or hundreds of bidding contracts to her ITT and can filter the bidding contracts according to their price, delivery time, reputation etc. Once Alice chooses the winning bid contract, and provided she has not finer details to negotiate, she digitally signs contract and sends copies to the bidder and an arbiter to setup the multisignature address.

The TradeNet

A long term outcome of supporting ITT contracts within OpenBazaar is the potential for it to become a 'TradeNet', as descibed by Mike Hearn (slide 25). The original proposal imagined the TradeNet to be a market infrastructure for applications, potentially distributed autonomous corporations/businesses, to interface with in order to purchase goods and services according to their programmed goals and profit motives. These applications would issue tenders for goods or services on the TradeNet, receive bids and automatically purchase contracts based on algorithmically-determined conditions (factoring in price, proximity, time etc).

A much more attractive alternative is for OpenBazaar to potentially faciliate ITT contracts for both individuals and distributed consensus/autonomous organisations for peer-to-peer exchanges of goods and services. This is achievable using Ricardian contracts as they are both human and application readable, permitting human-application exchanges without either party known the true identity of each other if so desired.

Service Listing

The second type of service contract is called a service listing, where service providers can advertise their services to potential clients in the hope of receiving a quotation request. Contrary to an ITT, where service providers seek out contracts to bid on, a service listing will be 'Yellow Pages' of individuals/organisations filtered according to the category/sub-category of services they provide. The service listing will be formatted as a Ricardian contract including the following fields:

  1. Category and sub-category of service provision
  2. Estimated prices
  3. Estimated time to complete certain services
  4. Availability
  5. Comments and special considerations
  6. Quotation response time

A potential client can request a quote from the a service provider by drawing up a fresh service contract (according their requirements) that includes a hash of the service listing. The inclusion of the hash indicates that the client is requesting a quote based off the specifications advertised by the service provider's service listing. From here, the contract is negotiated between both parties as described above prior to double and triple digital signing to initate the contract.

Good Performance Bonds

A surety bond can be created to cover a failed contract, which either partially or fully remediates the costs of the failed contract for the damaged party. However, as some conditions of the contract can fail without damaging the final outcome of the contract, smaller value surety bonds can be created to incentivise 100% contract fidelity. These smaller surety bonds can be called 'good performance bonds' (GPB).

For example, GPB may be written to penalise a service provider or supplier for failing to meet a contractually obligated deadline. Another example is a GPB for the client to follow the terms and conditions of the service specified in the contract (i.e. be at a certain place by a certain time).

The GPB can be factored as a deduction for the service provider's fee for the sake of simplicity, which can be carefully monitored by the arbiter. Within the contract, a GPB can be formatted within the following fields (using the example above):

{
  "good_performance_bond": {
    "condition_1": {
      "penalty": "7 mBTC",
      "description": "Failure to delivery goods before 9 am"
    },
    "condition_2": {
      "penalty": "5 mBTC",
      "description": "Failure to sign for delivered goods within 7 minutes of the drone's arrivate at the delivery address"
    },
    "condition_3": {
      "penalty": "2 mBTC",
      "description": "Failture to respond to enquires within 20 minutes"
    },
    "condition_4": {
      "reward": "5 mBTC",
      "description": "Item is delivered before 8.45 am"
    }
  }
}

The inclusion of GPBs would occur from the outset of the contract's formation, requiring both parties to digitially sign to indicate their agreement. The arbiter can verify the authenticity and integrity of these terms by both party's digital signatures and contract hashes, as per a normal Ricardian contract.

4.3 Lending

Index:

  1. Ricardian Loan Contracts
  2. Risk Management

Banks are centralised institutions that, among other things, offer credit to individuals, groups and corporations. Historically, banks were a nexus of borrowers and lenders, matching the supply of liquidity to the demand for credit. The primary role of a bank was risk management in the form of the due diligence required to assess if a potential borrower was a worthwhile investment. With the advent of nation-state money printing and fractional-reserve banking, whereby money is lent into existence and losses are publicly subsidized by inflation and bailouts, the traditional care of risk management for loans has all but been obiliterated.

Peer-to-peer (P2P) lending has emerged as a means to decentralise the oligopolistic hold that banks possess in every category for lending. While P2P lending is still in early days, regulatory pressure is mounting making P2P lending services using fiat dollars especially vulnerable to the legacy financial/political order. Using Bitcoin, this legacy threat is largely eliminated, but introduces new problems in the traditional approach of risk management. The purpose of this article is to suggest possible solutions to these problems and how they might be executed on a pseudonymous censorship-resistant marketplace like OpenBazaar.

4.3.1. Ricardian Loan Contracts

As with other goods and services on OpenBazaar, the loan is drawn up as a Ricardian-style contract that I will refer to as the loan contract for the rest of the article. The loan contract is initially written by the borrower and distributed/published on the OpenBazaar network, as the borrower is trying to convince the market to purchase their unmaterialized future good (a interest markup of the original loan amount).

Let us imagine a borrower, Bob, and a creditor, Alice:

Step 1: Debtor creates a loan contract

The loan contract specifies that Bob wishes to exchange 110 mBTC in 1 year for 100 mBTC now (i.e. Bob wants to borrow 100 mBTC). The interest rate is 10% p.a. The following fields are introduced in the loan contract:

1. Loan_amount: 100 mBTC
2. Loan_term: 1 year   
3. Interest_rate: 10% p.a.
4. Interest calculated: monthly
5. Payment schedule: monthly
6. Address and self-signature

Bob digitally signs the contract and publishes it to the network.

{
    "001": {
        "01_debtor": {
            "01_metadata": {
                "category": "loan",
                "category_sub": "fixed term",
                "contract_expiry": "30 days",
                "obcv": "b5.0"
            },
            "02_id": {
                "contact": {
                    "bitmessage": "",
                    "email": "alice@alice.com",
                    "subspace": ""
                },
                "guid": "zxc987",
                "handle": "alice",
                "onename": "+alice",
                "pubkeys": {
                    "bitcoin": "xxx",
                    "pgp": "xxx"
                },
                "role": "debtor"
            },
            "03_notary": {
                "guid": "abc123",
                "handle": "Acme Notary Service",
                "keys": {
                    "pubkey": "xxx",
                    "self_sig": "XXX"
                }
            },
            "04_loan": {
                "debt": "100 mBTC",
                "interest_calc": "monthly",
                "interest_rate_perc": "10",
                "keywords": [
                    "loan",
                    "10% pa"
                ],
                "loan_address": {
                    "btc_address": "xxx",
                    "self_sig": "XXX"
                },
                "repayments": "monthly",
                "term": "365 days"
            }
        },
        "02_signatures": {
            "bitcoin": "XXX",
            "pgp": "XXX"
        }
    }
}

Step 2: Creditor accepts the loan contract

Alice agrees with the contract and appends the following data:

  1. Network ID (plus any other ID data)
  2. Indicates the role of Alice as a creditor
  3. A schedule of repayment bitcoin addresses (i.e. an address for each month across the term of the loan)
  4. There are an estimated 12 repayment schedules in the example, so Alice attached 12 unique addresses for Bob to send each repayment
  5. Multisignature escrow details
  6. Multisignature address generated from the debtor, creditor, and notary
    • Redemption script
  7. Funds will be released from multisignature escrow to the exclusive control of the debtor after confirmation; notary stands by refund the creditor if a problem arises before confirmation
  8. TXID of the creditor funding the multisignature address

If Alice wants to change the terms of part of the contract, she can write, sign and send a fresh contract to Bob. If Bob disagrees, he can simply ignore the contract, or sign it if the change in terms acceptable (e.g. Alice increases the interest rate to 11% p.a., or changes the schedule to fortnightly repayments). Note that this is the only stage where this can happen as once both parties have signed the terms of the contract, it is locked-in as far as dispute resolution is concerned.

Step 3: Loan confirmed

Bob (debtor) confirms that the loan will proceed and appends a signed transaction releasing the funds into his control.

Step 4: The creditor signs and releases funds to the debtor

Alice (creditor) signs and broadcasts the transaction from step 3, releasing funds to Bob.

Step 4+n: Repayments

For every repayment, Bob appends to the loan contract evidence of the repayment addresses being funded along with the outstanding balance of the loan, until it is paid off.

4.3.2. Risk Management

1. Credit Ratings and Collateral

The process above has thus far described how the loan contract is created and processed for auditing purposes by the arbiter. However, it has not dealt with how loan contracts will be protected from fraud by bad actors on OpenBazaar. Traditionally, there are two major ways to manage risk for potential loans:

  1. Assess the borrower's credit rating
  2. Require collateral for the loan
Credit Rating

an estimate of the ability of a person or organization to fulfill their financial commitments, based on previous dealings.

As a credit rating often involves an individual disclosing their income and previous financial dealings to the creditor and other third parties, the concept of a traditional credit rating is incompatible with the goals and purpose of OpenBazaar. New and innovative solutions are required assess the credit-worthiness of an individual in a pseudonymous marketplace.

Collateral

something pledged as security for repayment of a loan, to be forfeited in the event of a default.

A borrower must provide collateral to the creditor before a loan is approved. Collateral can be any good belonging to the borrower that has an equivalent value to the amount being loaned. In case of a credit default, the creditor can physically possess the collateral to recover their losses.

2. Web of Credit

Taking the web of trust concept one step further, OpenBazaar can facilitate peers extending lines of credit to each other. If there is a successful trade between Alice and Bob, Alice may choose to extend a 5 mBTC line of credit to Bob. Bob can borrow this money at any time according to the prescribed conditions set by Alice. The funds can be kept in a 2-of-3 multisignature address, using an arbiter as a third signature. This line of credit can be publicly disclosed and audited by other peers. The aggregate of a pseudonym's line of credit becomes a powerful and informative risk signal for other peers, with risk being inversely proportional to the sum total line of credit.

The line of credit can be considered as collateral by a potential creditor, knowing that a pseudonym's line of credit can be called upon to satisfy a renumberation of second loan. For individual extending lines of credit, they have an opportunity to invest in successful and well-regarded trade partners.

3. Collateral as User-Created Assets

In OpenBazaar, collateral can be transferred by digitally signing possession of a user-created asset, represented by a Ricardian contract. Briefly, Jack may posses 0.1 ounces of gold and wants to exchange it for other goods and services on OpenBazaar. Jack writes a contract stating that he has possession of 0.1 ounces of gold. To sign ownership of that contract to another individual, Jill, Jack can create a fresh contract with the following data:

  1. A encrypted copy of the old contract using Jill's public key
  2. Updated ownership details (i.e. Jill owns 0.1 ounces of gold)

The new contract is then digitally signed with Jack's private key. Now, this entire process assumes that Jack actually has 0.1 ounces of gold behind the contract and is able to physically transfer the goods or their custody (if a third party, like a vault, is holding them). The burden of proof will be on Jack to demonstrate to Jill that contract is valid. Jack can also seek other highly rated (web of trust) third parties or arbiters to sign the initial contract after they are satisfied with Jack's proof.

Outside of the Ricardian contract model in OpenBazaar, user-generated assets from colored coins or other sources (Mastercoin, Counterparty, OpenTransactions etc), can also be offered as collateral for a loan.

Part 4: Collateral and Distributed Collateralized Trusts

What if a user like Bob is unable to provide sufficient collateral for the loan due to either: 1) his wealth status living in a developing country, or 2) providing collateral in the traditional sense would reveal his pseudonym's identity?

One possible solution is for Bob to purchase collateral from a distributed collateralized trust or dCT. A dCT is a collection of users that pool a certain value of funds in essentially a term deposit. This term deposit serves as collateral for a loan in the event that the borrower defaults. In return for this risk, the borrower pays each member of the trust a fee that makes up the effective interest rate of the term deposit. Using the example thus far, Bob purchases 100 mBTC collateral from a 10 member dCT at the price of 10 mBTC. Under this arrangement, each member of the dCT risks 10 mBTC for a term of 1 year for a return of 1 mBTC (or roughly 10% p.a.), paid for in advance by Bob's fee

Alternatively, Alice could forgo Bob's collateral in favor of a 10 mBTC downpayment upfront. However, Alice will not be compensated if there is a default on the loan. This option could be viable if Alice routinely lends funds to Bob and extends to him a sufficient level of trust.

dCTs however, confer a number of advantages:

  1. Overall level of risk is spread
  2. Multiple layers of due diligence
  3. Both the creditor and the dCT will need to evaluate the profitability of lending to Bob, decreasing the chances of spurious lending
  4. The dCT can also examine the track record of the creditor, Alice, for their success in picking borrowers
  5. The purpose of the loan can be interrogated, and if possible, funds can incrementally be released
  6. Promotes liquidity
  7. The creditor has, in effect, insurance in lending
  8. The level of risk that is an obstacle for the lender is now lower than the level of risk for each member of the dCT, making relatively capital-intensive loans possible

A dCT is not necessarily appropriate for small-medium sized loans, as a borrow can crowd-source the loan as the level of risk is especially low. However, it will be up to the creditor to evaluate their level of risk tolerance and what steps they take to manage that risk.

4.4 Financial Securities

Bounded Futures

A forward contract is an agreement to buy an item for an agreed price in future. For example it might be possible to agree to purchase a barrel of crude oil a month from now for $100. If in a month the market price of crude is higher than $100, then the contract has positive value. If the price is lower, the contract has negative value.

Value of bought futures contract in one month = item price in one month - futures price

Symmetrically, it is possible to enter a contract to sell crude in a month for $100. This gives the negative value of a bought future.

Value of sold futures contract in one month = futures price - item price in one month

The contract allows both sides to have an exposure to the market price of crude without owning the asset. For a fungible asset like oil it is not even necessary for to exchange the physical asset at the agreed sale time; buyer and seller can simply settle for the economic value of the contract (difference between the agreed futures price and the market price).

Futures contracts are widely used for currencies, equity indices (like the S&P 500), interest rates, bonds, commodities, and recently for more exotic risks like temperature and rainfall. These markets allow a far greater flexibility in speculation and hedging for market participants than would be available in the ordinary cash markets for the underlying assets. In many cases the futures market volume exceeds the cash market, and the price is first determined by trades in the futures market and later reflected in changes in the cash (or spot) price.

A difficulty with futures contracts is that it requires trust between contracted parties to pay the agreed contract value. If the price of crude increases to $150 in one month the buyer of the contract must have a mechanism to receive $50 from the seller (or equivalently a physical barrel for $100). This obligation must be backed by enforceable contract.

Futures traded on financial exchanges have a smart mechanism to solve this problem. Each side provides some amount of money to the exchange as collateral for their side of the agreement. If the market price of the contract changes (observed through other trades on the same item) one side has to provide additional money to the exchange. If they are unable to meet this call for extra collateral the exchange finds a new counterparty to the trade (buyer or seller). If the exchange is careful to always have sufficient collateral to absorb market price movements the contract will require no trust between buyers and sellers. Both sides do not even need to know about each other; the exchange is the legal counterparty to both sides.

This very elegant solution has a problem: the exchange must monitor the markets and make a guess at the probable size of price changes to determine how much collateral to require from each side. If the price movements are large or the contract is not traded often the exchange might not be able to find a suitable counterparty and be forced to take a financial loss on the contract. For a properly decentralized market a different solution is required that does not need monitoring of an exchange and also does not expose the parties to credit risk.

One solution is to have contracts that have limited losses or gains. Taking the example of the crude oil contract from the example earlier, a contract might only be exposed to the price risk if the price of crude was between $80 and $120. Each side of the contract would put up $20 in collateral and the value of the contract would be determined without any credit risk or need for margining.

The payoff of this new contract is a bounded version of a usual futures contract payoff:

(This assumes that the futures price is $100. A slightly more general contract payoff includes an offsetting amount if the price is different.*)

This bounded contract is more flexible than an ordinary future (an ordinary futures contract is a bounded contract with bounds at 0 and ∞). A series of contracts can be "chained" together, where the lower bound of one contract is matched to the upper bound of another. It is also possible to mimic the operation of a traditional futures exchange. As the asset price approaches the upper bound the exchange asks for additional collateral from the seller to buy the next bounded contract. In this way the operation of bounded contracts can be hidden from market participants who find trade in the bounded contracts too daunting.

A more subtle advantage of bounded contracts comes from their non-linear structure. A bounded contract is equivalent to buying a European call option with a strike at the lower bound and selling a call at the upper bound. Hence any market trading bounded contracts is also indirectly pricing and trading options. Usually it is relatively difficult to establish an options market in an asset because it requires sophisticated sellers to price the risk and a high volume in the underlying market for hedging. This makes options markets expensive and The existence of options in a market provides a much richer set of trading possibilities than with a simple cash or futures market. Options implicitly price expected volatility in the market (this is the essence of the Black Scholes formula – that hedging costs for options are dependent almost completely on the price volatility and not on the price direction). Options also implicitly provide a market estimate of the probability of the price entering a certain range. Imagine a bounded contract with a very small bound (say 99.5 to 100.5). This contract would be worth $0if the price is less than 99.5 and $1 if the price is more than $100.5. The market price of this contract is implicitly an estimate of the probability of the price exceeding $100.5. If the price of the contract is $0.5 the market believes the probability is 50%; if the price is $0.1 the market believes the probability is 10%.**

This allows traders to express more sophisticated views on the future price behavior than the crude up/down bet available through a future. The trader can speculate or hedge on the price achieving a certain range, or construct a trade to bet that the market priced probabilities are too wide (variance), or not reflecting sufficient asymmetry in price behavior (skewness). All these additional possibilities enhance the capability of the market to provide effective risk transfer.

However good things do not come for free, and there is a reason why spread contracts are not traded as frequently as futures on exchanges. The existence of multiple contracts divides the market volume between the contracts and makes trading in large size more difficult and costly. This is a serious drawback but there are mechanisms to moderate the problem. When a contract is offered for sale or purchase some traders might be willing to “convert” the contract into a nearby bound, simultaneously buying the one contract and selling the other. In this case a contract bid or offered at one bound would immediately and automatically provide volume to nearby bounds. This conversion service could be provided by the exchange itself, or by dedicated specialized market makers who would propagate liquidity amongst contracts in the hope of receiving up a small profit on average.

Bounded futures contracts are natural structures for decentralized markets where trading volumes are likely to be patchy and trust difficult to establish. Parties to the contract can determine how much risk they want to be exposed to and for how long. This removes the usual problems of margining (collateral) from the exchange in exchange for creating a problem by dividing liquidity between multiple contracts. But on net this trade is worthwhile: it allows a completely decentralized and autonomously operating futures market and an extraordinary flexibility of financial structures.

Example of a bounded futures contract as a hedge for a sale contract

Suppose we have the following scenario:

Chair spot price: 0.01BTC BTC spot price: $300 One month futures price for BTC $300. Chair in USD: $3

We agree to buy the chair to receive 0.01BTC in one month and wish to hedge the USD/BTC exposure.

To hedge with a normal futures contract, we agree to sell 0.01BTC in one month (short selling - shorting - bitcoin) for the futures price of $300/BTC ($3). Any changes in the price of BTC are fully hedged.

To hedge with a bounded futures contract we agree to sell 0.01BTC in one month for the futures price of $300/BTC ($3) bounded between 250USD/BTC ($2.5) and 350 USD/BTC ($3.5).

If the price of BTC after a month is at the upper bound ($350), the contract to sell 0.01BTC for $300 ($3.5) has a market value of -$0.5 (i.e. $3 - $3.5 = -$0.5). At the lower bound ($250) the contract is worth $0.5 (i.e. $3 - $2.5 = $0.5).

Both parties to the bounded futures contract put up $0.5 in collateral, in the multisignature escrow address, to cover their the maximum possible loss.

If the price of BTC/USD varies less than 50% the bounded futures contract provides a perfect hedge. If it moves more in either direction (above $350 or below $250) then the hedge is only partial.

(*) This is summarised by the following:

<img src="http://s28.postimg.org/6019zqdwd/Equation_2.png" width="400px"/>  
where F is the bounded contract "price" which makes the contract a fair trade for both parties. A more general form is:  
<img src="http://s9.postimg.org/w954bx9wf/Equation_3.png" width="200px"/>  
(**) In the limit as the bound approaches zero this is known as the “risk neutral” probability. This allows a probability distribution (the “risk neutral distribution”) to be constructed across the range of price where the contract trades.

2. Bounded Futures Ricardian Contract for OpenBazaar

This is an example of a bounded futures contract that may be issued in OpenBazaar:

{
  "001": {
    "listing": {
      "metadata": {
        "obcv": "0.1",
        "category": "Securities",
        "subcategory,": "Bounded Futures",
        "Nonce": "XXX-XXX",
        "Expiration": "XXXX-XX-XX XX:XX"
      },
      "futures_contract": {
        "item": "Wheat",
        "units": "30 bushels",
        "current_price_per_unit_btc": " 0.02",
        "price_total_btc": "0.6",
        "term_days": "5 days",
        "limit_btc": "0.05",
        "spot_price_source": "http://data.tradingcharts.com/futures/quotes/W.html"
      },
      "issuer": {
        "guid": "b5016e193656d33693a38bc2dbea7c80440c09ee",
        "handle": "drwasho",
        "legal_address": "",
        "pubkeys": {
          "pgp": "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=G1fD",
          "bitcoin_pubkey": "044448c02963b8f5ba1b8f7019a03b57c80b993313c37b464866efbf61c37098440bcdcc88bedf7f1e9c201e294cf3c064d39e372692a0568c01565b838e06af0b"
        }
      }
    },
    "signatures":{
      "pgp": "XXX",
      "bitcoin_key": "XXX"
    }
  }
}

Following the creation of the contract, the buyer would submit a bid offer on the contract. Involvement of the notary along with digitial signatures and counter-signatures would proceed as per normal.

Above, drwasho is locking in the purchase (in 5 days) of 30 bushels of wheat at a current price of 0.02 BTC per bushel (total price: 0.6 BTC). As this is a bounded futures contract, drwasho places a limit on his exposure to price volatility equal to 0.05 BTC. In other words, drwasho is going long on wheat, setting a maximum profit/loss margin of 0.05 BTC. If in 5 days the price for 30 bushels is > 0.65 BTC, drwasho will withdraw 0.1 BTC from the multisignature escrow (his original 0.05 BTC and the 0.05 BTC from the losing counterparty). If the price is < 0.55 BTC, drwasho will lose 0.05 BTC from the multisignature escrow address. Remember, the intention of these contracts are to hedge against price volatility, not necessarily trade the full value of the commoditity to be hedged!

4.5 Distributed Currency Exchange

OpenBazaar allows for the decentralised exchange of types of currencies using the flexible Ricardian contract system. Currency exchanges are not limited trades between crypto-currencies, but can also facilitate exchanges with fiat currencies using reverisble and non-reversible payment systems.

Fundamentally, currency exchanges require a matching of buy and sell orders at a certain price for a given volume. Firstly, buy and sell orders will be created and issued as a Ricardian contract, formatted according to a specialised 'currency' template in OpenBazaar. Secondly, matching buy and sell orders theoretically will be mediated over exchange nodes, which may also function as arbiters for each exchange. Alternative, buy and sell orders may be matched over the OpenBazaar distributed hash table. Finally, private exchanges can be made between peers, using OpenBazaar to merely faciliate the signing/counter-signing of the contract and finding an arbiter for the trade. After matching buy and sell order, the use of Bitcoin multisignature transactions is the key to managing counterparty risk for an exchange between different crypto-currencies, irrespective of whether Bitcoin is the final currency to be exchanged.

Currency contract can be further sub-categorised into:

  1. Crypto-Crypto currency exchanges
  2. Crypto-Fiat currency exchanges
  3. Fiat-Fiat currency exchanges

1. Crypto-Crypto Currency Exchanges

To create a currency Ricardian contract for a crypto-crypto exchange, a seed contract is prepared with the following data fields:

  1. Crypto-currency pair (e.g. Litecoin/Bitcoin; LTC/BTC)
  2. Exchange rate for the currency pair (e.g. 0.01637)
  3. Type (i.e buy, sell)
  4. Size (i.e. amount of the currency to buy/sell)
  5. Payment address

For example, Alice desires to purchase 5 litecoin for a price of 0.01637 LTC/BTC (0.08185 BTC total). She draws up the following seed contract and broadcasts it on OpenBazaar:

{
    "OpenBazaar Contract": {
        "OBCv": "0.1",
        "Category": "Currency",
        "Sub-category,": "Crypto-Crypto",
        "Nonce": "356a192b7913b04c54574d18c28d46e6395427ab",
        "Expiration":"2014-08-29 12:00:00"
        },
    "Seller": {
        "NymID": "61768db8d1a38f1c16d3e6eea812ef423c739068",
        "NodeID": "abc123",
        "BTCuncompressedpubkey":"044448c02963b8f5ba1b8f7019a03b57c80b993313c37b464866efbf61c37098440bcdcc88bedf7f1e9c201e294cf3c064d39e372692a0568c01565b838e06af0b",
        "publicKey": [
            "xsFNBFODLW8BD/9rmoBRBASaZuNpPBG+Gj7/aJcE7aQ4Sti7lKaERFD7/rHd",
            "WHm+o+FnyQvxpkOuuU6G4q739tP5ZqHx/bn9rhpAKKa+o7es70jlpenHyge4",
            "0QyIU1/9jXzwlMsXkq9XfbOhqtgiBRpeZ83/ZjUsf5/wQXhrGWvG4rnKj5kh",
            "YNq8PHzqJO21cDcD7LJy6yPuOgrBfb4MMa3+9lauIZ5Ye2kXR4m1OuWrig0M",
            "7SwgFZwo3GbmcWe5KCK60nHW0AZh47B/yC18s/uR3t2bGrkQwL6AgTiOd2hX",
            "/K2l1ccgIPnWo1s/5fMc7HiGpPkioOYhWgDm+2bimh56D2Tq7ikZQSDZIhw4",
            "2pOQCevN/efak7vc2vaaaKqGreF8EwQ5vahF9bS6aNzXzdG1t6PYVAIupdWz",
            "Ct0vrZr1ynBaIEEBJlFuI3vEyp+X85BVqV9B7gWbcE6vLeUPUB/Nu4NEdg5V",
            "4Np+URFQvW9NKfN04kGfuEViVe0sfgSEc86h+eJ3gWTI8NdhJZdRkzKzlB7Q",
            "FzMfL0TzxKSkOSu47eWx64e4xsyvkAVirkDb5VRzoeOOpJ/5ZOE1Cv8XJWEU",
            "Zd/WAyp60LT2Ga8mCqhUrPAkcQKsPhccEn23mxIH8Pt3xWfnDFqtma7Tu2fB",
            "CM4UKpd/dAjTVnZNNjSuBb+4SGBuGiUkA3yvdwARAQABzR1MaW9uZWwgRGVu",
            "dCA8bGlvbmVsQGRlbnQuY29tPsLBcgQQAQgAJgUCU4Mt1gYLCQgHAwIJEKnO",
            "FXGYSKNNBBUIAgoDFgIBAhsDAh4BAAAzQQ/9GArtJ4cNqPqM//NJCsQHCy35",
            "mKOpErbEkia/U10wlISDYV0S3fJJ+ktE/RSF1ZU+2JMf3Hl4q7hYPsFxPvfa",
            "yjRL48WBXI/V31zLvZUuH4reut4QLM4e6eAugS3lT+p8jU7mS7audZfUW65/",
            "VL3ZXJs8QhW52LqffkhAJLQauXBy0gE7+ndbGRVxrquINt2sTZFLBaDOpLr8",
            "4Aiq+UYunRUOmM7lpMnuErTkTe670Pxsu+8Ta8r+bedXhNIbYcMTgoJLOBLX",
            "IdL3G7ix5y5ebw0eQXTfX6QfW//er9NOi0lWVtplrYFoQ98kS19/uEta4P7r",
            "kMqZGBpPc7Ztr3zdeNwmbU3oVOv88ecizuvv3rwMDN5juUZ/KP0vQePA7LEd",
            "pGLdTpBMmwd5t6XArso0pDZl4J6YxVZ5HoIYlw2a648VgF0nli11zzix/YKt",
            "MSRVOwubuo0YGP/cRJy9qVawNU79wTHtnva86orGuQ5d9H/F7S2+f93u87nG",
            "5TNnI5ORXWzAHkJ3VU6SDzALs3K9PbzTSu4biSsMFSll2cZjZw2INsH9+gNO",
            "CWzwS7vROVxuZFQolyuWmBfBwVq5U+S8gmRJELkblR+jXetY5e8T2Cv23Kef",
            "Bj6LBv1HpiUMD6KX4cASS94tMdLlJqa78Yl7A35froh30Tq3wfm1KSX7SuTO",
            "wU0EU4Mt2AEQAIQzWvnLqtZP9nhWGcGqRwoZP0RJHmnbCpVmmVaoj2I/36k7",
            "PcuYs1xbc9Qt0gBpCQiskIjmCKVEcs+Dfj960qRxzrVfUQ/O09MrI2eMekhY",
            "nC+jlBNXc22CgH1ESodZDCZf2iA9qjAjd8swLotJ2v0Mw6GLmuLmejo2M3kV",
            "/jnQJW5ePHd/Wyw45yA1TJv75UhHZ4mo3/MYPBZnSt624JBt/+T4++XaG1kM",
            "Df5Ku63SEwhkz/nGpyW4BYTa56Pd/zKVxoxW5SfGfgREw8aw09jaApkfz9fy",
            "GAXcptFWCAvDDfxSCKiMNFBGzuXmgsB3GmEhaOpA9YwCy5TFPWvJ2U+wZ8DN",
            "M2JMGgwEL+AfHPa9zSH7fXppF95zpJRMpS0oLM3Rk7OxH+jF5xj+tzNJlBEU",
            "drfIw3J6ZZD0wFSZUx4/5Wqa7nCDl/FnrYPXevZXL6eaSsY5umeTNveLLLz1",
            "SYq+GtRqBgON7fOZbKNxw2udAYpufNX4HXvf/Y/FBf1zrUtxf035a+MmAtSj",
            "Kbf6yUI0BcwNLVBtyMQ6npL0942hH1T37szIL3TT2RZRifSs8u22oZVOxRaE",
            "yZrRdYrtQpz547rQMJ76a4mplmBGjdMv/ksvicVh1SJ7f+YhtGkUcDWC0CUY",
            "xnY/jAEL34muSZadG4CAKk7w3jJwryMbE6Y5ABEBAAHCwV8EGAEIABMFAlOD",
            "Lh8JEKnOFXGYSKNNAhsMAACzog//R4yBYDXurrsyFpPS2ndCwm/F0yxIVMYx",
            "5n/qWxrt+1Yv8sc9PVSLnTilqoVjJIokq6UkpATcmZOxSthCXYX1BjmQdjnl",
            "z6YGZHWKYkT2BPOJTHvcchSKnx2vn+DIlVIyJjvo6T4zeUVl99XJwWN7kNJ+",
            "NrlcLzqzksNFW8S6pndkBjn5bC/CzZKgh/KHX7L7ibc3jICgI4MZZLjapf+Y",
            "4mDmzPoSLrQBHMzAAShj3Li6IEdz0C6KrfGWzVcCHHfpOhWY+A0y4ztOKEEW",
            "UlrlTPPgxuEbbspee5caBb6mVsvADwn2/wJ2LSYUa0jBSXnQy5Az94xbfbJt",
            "LqEn7uWsJ9HE0kXOLk89BCSguYog86ptmUXG4uDT5S9zlScR5XC3EJOKpvYU",
            "NchZS1ydMoerb3VLtVY6pQUqRvSu9+HrouHpp2h2+6B83Eh7gTy7BSqc7TIh",
            "SsfNIt5nJLCLzWiGst9CS6XuuLzf9JAH85m9ZH8AuKfAW2fICX8KyiBicH/s",
            "eGHqdJ7buEidG3WbA3vvGePma2cXDTfBRcddUwvoLTmCxOMt8IPEwuUq0tnS",
            "oJaCHMMN+csbgCTLb+CMvVjzGbgI8Z3LlKCe1siBh6iDvad7/pIEZm7T7OOC",
            "FFN8mcvExvCZU6mpCGRg7JmXuI5gzq+O3A+x2virikGYG7NjK8w=",
            "=dDLn"
            ]
        },
    "Currency": {
        "CurrencyPair": "LTC/BTC",
        "ExchangeRate": "0.01637",
        "Type": "Buy",
        "Size": "5",
        "PaymentAddress": "Lbnu1x4UfToiiFGU8MvPrLpj2GSrtUrxFH"
        }
}

A prospective buyer only needs to submit a bid offer by appending the following data to the seed contract:

  1. Buyer details
  2. Payment address

As with all Ricardian contracts on OpenBazaar, digital signatures are required at each step.

2. Crypto-Fiat Currency Exchanges

For a crypto-fiat exchange, the seed contract will have the following data fields:

  1. Crypto-Fiat currency pair (e.g. Bitcoin/US dollar; BTC/USD)
  2. Exchange rate for the currency pair (e.g. 0.00167)
  3. Type (i.e buy, sell)
  4. Size (i.e. amount of the currency to buy/sell)
  5. Payment address/bank details (this data field can be blinded until funds are transferred to the bitcoin multisignature escrow address)

For example, Alice desires to purchase 5 bitcoin for a price of 0.00167 BTC/USD ($3000 USD total). She creates the following seed contract and broadcasts it on OpenBazaar:

{
    "OpenBazaar Contract": {
        "OBCv": "0.1",
        "Category": "Currency",
        "Sub-category,": "Crypto-Fiat",
        "Nonce": "356a192b7913b04c54574d18cd8d46e6395427ab",
        "Expiration":"2014-08-29 12:00:00"
        },
    "Seller": {
        "NymID": "61768db8d1a38f1c16d3e6eea812ef423c739068",
        "NodeID": "abc123",
        "BTCuncompressedpubkey":"044448c02963b8f5ba1b8f7019a03b57c80b993313c37b464866efbf61c37098440bcdcc88bedf7f1e9c201e294cf3c064d39e372692a0568c01565b838e06af0b",
        "publicKey": [
            "xsFNBFODLW8BD/9rmoBRBASaZuNpPBG+Gj7/aJcE7aQ4Sti7lKaERFD7/rHd",
            "WHm+o+FnyQvxpkOuuU6G4q739tP5ZqHx/bn9rhpAKKa+o7es70jlpenHyge4",
            "0QyIU1/9jXzwlMsXkq9XfbOhqtgiBRpeZ83/ZjUsf5/wQXhrGWvG4rnKj5kh",
            "YNq8PHzqJO21cDcD7LJy6yPuOgrBfb4MMa3+9lauIZ5Ye2kXR4m1OuWrig0M",
            "7SwgFZwo3GbmcWe5KCK60nHW0AZh47B/yC18s/uR3t2bGrkQwL6AgTiOd2hX",
            "/K2l1ccgIPnWo1s/5fMc7HiGpPkioOYhWgDm+2bimh56D2Tq7ikZQSDZIhw4",
            "2pOQCevN/efak7vc2vaaaKqGreF8EwQ5vahF9bS6aNzXzdG1t6PYVAIupdWz",
            "Ct0vrZr1ynBaIEEBJlFuI3vEyp+X85BVqV9B7gWbcE6vLeUPUB/Nu4NEdg5V",
            "4Np+URFQvW9NKfN04kGfuEViVe0sfgSEc86h+eJ3gWTI8NdhJZdRkzKzlB7Q",
            "FzMfL0TzxKSkOSu47eWx64e4xsyvkAVirkDb5VRzoeOOpJ/5ZOE1Cv8XJWEU",
            "Zd/WAyp60LT2Ga8mCqhUrPAkcQKsPhccEn23mxIH8Pt3xWfnDFqtma7Tu2fB",
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            "nC+jlBNXc22CgH1ESodZDCZf2iA9qjAjd8swLotJ2v0Mw6GLmuLmejo2M3kV",
            "/jnQJW5ePHd/Wyw45yA1TJv75UhHZ4mo3/MYPBZnSt624JBt/+T4++XaG1kM",
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            "FFN8mcvExvCZU6mpCGRg7JmXuI5gzq+O3A+x2virikGYG7NjK8w=",
            "=dDLn"
            ]
        },
    "Currency": {
        "CurrencyPair": "USD/BTC",
        "ExchangeRate": "0.00167",
        "Type": "Buy",
        "Size": "5",
        "PaymentAddress": "1HZwkjkeaoZfTSaJxDw6aKkxp45agDiEzN"
        }
}

On the other side of the trade, the buyer (Bob) submits a bid offer by appending the following data to the seed contract:

  1. Buyer details
  2. Bank details (blinded)
  3. The bank details can be hashed and included in a single data field
  4. Later the source bank details can be revealed to the buyer and arbiter, who can verify the authenticity of the hash

The contract with the buyer's digital signature is sent back to the seller (Alice), which can be signed and forwarded to the arbiter for creation of the multisignature escrow address. Bob transfers 5 BTC to the multisignature address and reveals his bank details to Alice and the arbiter. Bob then awaits for the fiat funds to arrive in his account before signing a release of the funds from the multisig address to Alice.

Chargeback Risk

If an irreversible payment processor (e.g. OKPay) is used, then the multisignature bitcoin address is a sufficient means of managing the exchange risk as chargebacks are theoretically impossible. However, if Alice in this case did not use such an non-reverisble payment processor, the trade can still occur with the punative measures to appropriately manage the charageback risk:

  1. Probation
  2. The purchased bitcoin funds are kept within the multisignature address until the chargeback risk duration has elapsed. This period will be variable, depending on the bank that is used.
  3. Surety bond
  4. The seller can post a surety bond (refundable security deposit of bitcoin within multisignature address) for the partial or full amount of funds to be exchanged. This allows the seller to access the exchanged bitcoin immediately. While this appears to be a zero-sum game for a single trade, a regular trader may set aside a pool of funds to be re-used as a surety bond after every trade.

3. Fiat-Fiat Currency Exchanges

For a fiat-fiat exchange, the seed contract will need the following data fields:

  1. Fiat-fiat currency pair (e.g. Euro/US dollar; EUR/USD)
  2. Exchange rate for the currency pair (e.g. $1.36 EUR/USD)
  3. Type (i.e buy, sell)
  4. Size (i.e. amount of the currency to buy/sell)
  5. Bank details (this data field can be blinded until funds are transferred to the bitcoin multisignature escrow address)

For example, Alice desires to purchase $100 Euro for a price of $1.36 EUR/USD ($136.48 USD total). She creates the following seed contract and broadcasts it on OpenBazaar:

{
    "OpenBazaar Contract": {
        "OBCv": "0.1",
        "Category": "Currency",
        "Sub-category,": "Crypto-Fiat",
        "Nonce": "356a192b7913b04c54574d18cd8d46e6395427ab",
        "Expiration":"2014-08-29 12:00:00"
        },
    "Seller": {
        "NymID": "61768db8d1a38f1c16d3e6eea812ef423c739068",
        "NodeID": "abc123",
        "BTCuncompressedpubkey":"044448c02963b8f5ba1b8f7019a03b57c80b993313c37b464866efbf61c37098440bcdcc88bedf7f1e9c201e294cf3c064d39e372692a0568c01565b838e06af0b",
        "publicKey": [
            "xsFNBFODLW8BD/9rmoBRBASaZuNpPBG+Gj7/aJcE7aQ4Sti7lKaERFD7/rHd",
            "WHm+o+FnyQvxpkOuuU6G4q739tP5ZqHx/bn9rhpAKKa+o7es70jlpenHyge4",
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            "7SwgFZwo3GbmcWe5KCK60nHW0AZh47B/yC18s/uR3t2bGrkQwL6AgTiOd2hX",
            "/K2l1ccgIPnWo1s/5fMc7HiGpPkioOYhWgDm+2bimh56D2Tq7ikZQSDZIhw4",
            "2pOQCevN/efak7vc2vaaaKqGreF8EwQ5vahF9bS6aNzXzdG1t6PYVAIupdWz",
            "Ct0vrZr1ynBaIEEBJlFuI3vEyp+X85BVqV9B7gWbcE6vLeUPUB/Nu4NEdg5V",
            "4Np+URFQvW9NKfN04kGfuEViVe0sfgSEc86h+eJ3gWTI8NdhJZdRkzKzlB7Q",
            "FzMfL0TzxKSkOSu47eWx64e4xsyvkAVirkDb5VRzoeOOpJ/5ZOE1Cv8XJWEU",
            "Zd/WAyp60LT2Ga8mCqhUrPAkcQKsPhccEn23mxIH8Pt3xWfnDFqtma7Tu2fB",
            "CM4UKpd/dAjTVnZNNjSuBb+4SGBuGiUkA3yvdwARAQABzR1MaW9uZWwgRGVu",
            "dCA8bGlvbmVsQGRlbnQuY29tPsLBcgQQAQgAJgUCU4Mt1gYLCQgHAwIJEKnO",
            "FXGYSKNNBBUIAgoDFgIBAhsDAh4BAAAzQQ/9GArtJ4cNqPqM//NJCsQHCy35",
            "mKOpErbEkia/U10wlISDYV0S3fJJ+ktE/RSF1ZU+2JMf3Hl4q7hYPsFxPvfa",
            "yjRL48WBXI/V31zLvZUuH4reut4QLM4e6eAugS3lT+p8jU7mS7audZfUW65/",
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            "FFN8mcvExvCZU6mpCGRg7JmXuI5gzq+O3A+x2virikGYG7NjK8w=",
            "=dDLn"
            ]
        },
    "Currency": {
        "CurrencyPair": "EUR/USD",
        "ExchangeRate": "$1.36",
        "Type": "Buy",
        "Size": "100",
        "BankDetails": "8c2226df637baf568e26c042dc376f5d4a1492e8"
        }
}

The buyer, Bob, submits a bid offer for the seed contract by appending:

  1. Buyer details
  2. Bank details (blinded)

The double-signed contract is sent to the arbiter for the creation of the multisignature escrow address. Both the buyer and seller transfer bitcoin to the address as collateral for their fiat exchange.

As for chargeback risk, it is clearly preferable for both parties to use a non-reversible payment processor. In the absence of this, the bitcoin collateral would not be released until the chargeback risk period as elapsed.

Listing and Matching Buy/Sell Orders on OpenBazaar

1. DHT Listing

Following the Bitsquare model, the buy and sell orders are listed in the DHT (for a fee, which I'd like to avoid). The client then matches the buy and sell orders and places both parties in contact with each other over the network. Contracts can be found using the inverse keyword search on OpenBazaar's DHT, which is a Kademlia-like P2P network.

2. DarkPool

This model uses a private means of matching buy and sell orders, which I think also encompasses private P2P exchanges between parties that have already discovered each other. In this case, the transfer is fairly straightforward and would proceed as I described under the crypto-crypto section.

3. Exchange Nodes

This introduces the concept of a node or groups of nodes where buyers and sellers submit their orders to (Ricardian contracts as described in the article). The exchange matches the buy and sell orders, and is the arbiter for transactions. It will also have responsibility for broadcasting the price on their exchange. So this takes advantage of the benefits of centralisation, but if the exchange is taken out it doesn't cripple the ability for individuals to make currency exchange.

4.6 Insurance

Insurance is a valuable service that is often misinterpreted, over-regulated, and out of reach for many people. On OpenBazaar, insurance is contextualized as a service that can be offered by anyone or group, leveraging:

  1. The clarity of terms and conditions set out in a Ricardian contract
  2. An open marketplace for competing insurance policies and service providers
  3. The transparency that crypto-currencies provide via the blockchain

Ultimately, the market will decide the most appropriate insurance service and contract models for OpenBazaar. In this article, we propose some potential implementations as a primer for future development.

1. Insurance Services

Insurance services fundamentally offer:

  1. A pool of funds to offset a cost that exceeds the capacity of the client to pay within a timely manner
  2. A pool of funds to compensate another party that has been wronged by actions of the client, which addresses their capacity to pay within a reasonable time frame
  3. A dispute resolution organization that represents the interests of the client

These services are of course provided through the lens of risk assessment to dictate the price of:

  1. The insurance premium (regular cost of the policy)
  2. The excess (fee paid when insurance is triggered).

Traditional business models of insurance mirror a fractional reserve system in that funds are predominantly reinvested on the statistical reality that it is unlikely for all or even most policies to be triggered at once. Whether this model survives the blockchain era is unknown. The transparency that the blockchain provides may alter consumer preferences for how insurance funds are managed; proof of solvency may be an inescapable market-imposed regulation. If so, insurance providers will need to prove that the proportion of funds kept in reserve and those reinvested are at the levels that the policy claims. Alternatively, conservative insurance providers may keep 100% reserves and seek to raise profits only by fees incorporated into the premium and excess.

Whatever business model an insurance provider adopts, the terms and conditions of their policy will be listed within a Ricardian contract in OpenBazaar, with digital signatures as the unmistakable evidence of agreement.

While the various fields necessary for a comprehensive contract are difficult to predict, the seed contract may contain the following core data fields:

{
    "OpenBazaar Contract": {
        "OBCv": "0.1",
        "Category": "Insurance",
        "Sub-category,": "Car-Insurnace",
        "Nonce": "01",
        "Expiration": "2014-06-29 12:00:00"
    },
    "Seller": {
        "NymID": "Samuel Patterson",
        "NodeID": "SamPatt",
        "BTCuncompressedpubkey": "044448c02963b8f5ba1b8f7019a03b57c80b993313c37b464866efbf61c37098440bcdcc88bedf7f1e9c201e294cf3c064d39e372692a0568c01565b838e06af0b",
        "PGPpublicKey": [
            "mQENBFMKYTUBCADD6kIAjBlJ2Q0NEd97aia0BSBibO1C2lVemWig5cNATeob1McWoEo3QznZ",
            "f9LaRsuo+ryyqEeXx4p9m9FG/TDeeZvOaiSo2Pg5MtgAdxwJK3ZQ+6b6DjrfYRZplD4qVsQd",
            "/GhxDr733NBdTpfvE8rYrAttNeU8P9vZpJuU+ESSRNb8Sbgfrym2i7xeMP6/xnyfTunXti7x",
            "sJzFkGIoF1dc+HntP2b9oSy1y0P5n0FdGt7IaEEtN1AZwAfFJ0obSlXiVdWdPwyambAzj93V",
            "XD//KxXyxAHjqFD+sdqDzqxBTZ/MC/YCMU1UQ5hvWsx7FRqubLhyMB1p1ycvdnX6nqdTABEB",
            "AAG0KFNhbSBQYXR0ZXJzb24gPHNhbUBzYW11ZWxycGF0dGVyc29uLmNvbT6JATkEEwECACMF",
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            "yebij7AblNTCSgWXm/QV+ejZH0bR91FbtjdVKoFo6qrL04zuRbBFm2wHv+CYNKwRR2PPcCB/",
            "dQaGpQ==",
            "=IB1U"
        ]
    },
    "Insurance": {
        "PolicyNonce": "abc123",
        "Term": "12 months",
        "Type": "Car",
        "PolicyValue": "20 BTC",
        "Reserve": "20 percent",
        "Coverage": {
            "Fire": "True",
            "Water": "True",
            "Flood": "False",
            "AccidentalCrash": {
                "IFCauseClient": "False",
                "IFCauseNotClient": "True"
            }
        },
        "Client": {
            "Payments": "0.1 BTC",
            "PaymentFreq": "Monthly",
            "Excess": "0.25 BTC"
        }
    }
}

When a client takes out an insurance contract with a provider, a multisignature transaction is created in combination with the notary's pubkey. The client's insurance funds are paid to the multisignature transaction according to the payment schedule specified within the insurance contract. Under the client and/or notary's supervision, the insurance provider cannot extract funds beyond the reserve amount stated in the contract. For large insurance policies, a notary pool can be used for redundancy's sake and to minimize risk for client and insurance provider. Before an insurance contract is signed by the client and insurance provider, the latter can provide evidence that they have sufficient funds to payout the full value of the policy (e.g. 20 BTC in the case of the insurance contract above).

In the event that the client makes an insurance claim, the client can provide the relevant detail and evidence of the claim to the insurance provider. For a successful claim, the insurer can transfer the required amount directly to the client. If the insurance provider rejects the claim, the client may flag a dispute.

2. Transaction Insurance on OpenBazaar

It is possible for users to take out insurance for trades made over OpenBazaar. The purpose of the insurance in this context is to guard against the scenario where a user is subject to a loss of funds and/or goods that cannot be recovered. This loss is not necessarily due to fraudulent activity, but also covers the accidental loss of funds/goods in transit (i.e. including acts of God).

For example, Alice sells a cat to Bob on OpenBazaar: 1. During transit, the cat escapes and an empty cage is delivered to Bob. Bob refuses to sign a multisignature transaction releasing funds to Alice based on the a perceived violation of the contract. 2. Alice and Bob flag a dispute and engage an arbiter to weigh up the case in order to determine who should receive the funds. 3. During the dispute resolution process, Alice provides sufficient evidence that the cat was delivered alive and well to the courier. Likewise, Bob is able to provide evidence that the cage was delivered empty to him by the courier.

If the courier in this example did not have a presence on OpenBazaar (i.e. outside of its jurisdiction), the arbiter may have no choice but to rule in favor of Bob (according to their arbitration policy). The arbiter instructs the notary (the third signature of the 2-of-3 multisignature escrow address between Alice and Bob) to create and sign a transaction releasing the funds back to Bob.

In this case, Alice was not at fault but ended up suffering the consequences of an uncommon accident, which is an ideal scenario for insurance to cover. If Alice had taken merchant insurance for her trade with Bob, she could make a claim to cover the value of the lost good in the failed trade. The insurance provider may launch their own investigation before deciding to award Alice the insurance funds.

If the courier in this example did have a presence on OpenBazaar, Alice's insurance provider may contact the courier directly or the courier's insurance provider. In the latter case, compensation to Alice can be paid out of the courier's insurance policy funds (most likely after arbitration between both insurance providers).

4.7 Crowd Funding

Article Pending

4.8 Prediction Markets

Article Pending