Mobinsure
Peer to Peer Mobile Insurance where claims paid out are dependant on whether the IMEI of a phone is blocked. It is assumed that if an IMEI is blocked, determined by the IMEI oracle, the phone is unusable and therefore the policy holder deserves a payout. Current implementation is for a single premium and payout value. Many assumptions and improvements are littered as comments around Mobinsure.sol and many are referred to here as well.

Tech used
CryptoCompare API - to fetch conversion data from GBP to ETH (would be extended to other currencies in future). Oraclize - to communicate with CryptoCompare. It also fakes Oraclize usage for fetching the IMEI data.

Basic Walkthrough
The contract has two public functions for its main usage. buyPolicy() which requires a mobiles IMEI. It also accepts the current blocked status of the IMEI for demonstration purposes only, this would be got from the IMEI oracle in reality. Before registering, it does a price check using oraclize to check the payment sent is equal to GBP premium value in ether. If the payment is correct it then does an Oraclize request to fetch the IMEI data and checks the IMEI is not already blocked, if it isn't it then it registers the policy to that IMEI and the senders address.

Once an IMEI is blocked, and the IMEI oracle will report this, the user can claim using makeClaim() which accepts the IMEI to determine the policy. It also accepts the current blocked status of the IMEI for demonstration purposes only, this would be got from the IMEI oracle in reality. Before making a payout it checks the IMEI policy is within it's insured period then creates an Oraclize request to fetch the IMEI data to check it is now blocked, it then makes a payout to the account that made the policy and invalidates the policy for further claims.

Example usage
Requires npm install to install web3 package to local dir. Removal or updating of Oraclize interface in the Mobinsure.sol depending on if you're using the ethereum-bridge. Then from a truffle console migrate to deploy the Mobinsure.sol contract. ts.js is a test script for interacting with the Truffle deployed contract. It includes a bunch of JS functions calling functions from the Mobinsure.sol contract and some commented example execution. To test, uncomment buyPolicy() function calls and comment makeClaim() call. Execute in truffle console with exec ts.js. Wait for the log statement that verifies the price check has been completed. Then comment buyPolicy() function calls and uncomment makeClaim() call, execute ts.js again to test claiming.

Necessary extensions
There are no free providers of the IMEI data that this system requires. In the full system we would require an incentivised policy value weighted voting mechanism for determining the IMEI data provider and a mechanism for allowing the IMEI data provider to take payment (payment also determined by vote). To bootstrap we would find an initial IMEI provider not voted in by policy holders.

Currently only one policy is available. We should have multiple policies, one for each device. When buying policies, we should check the IMEI number to find the device and it's age and use this to determine the premium and the payout for the policy. The premiums and payouts should also be recalculated when policies are bought (for the next policy purchase) dependant on the balance in the contract and previous number of claims.

A user must pay ETH value of a GBP amount within a specified margin. Currently unimplemented due to difficulty getting the ETH value in WEI from the price checker. Could easily write a function to fix this in future.

Integrate a way to change the price checker source incase it stops providing the data expected.

The payout amount in ETH must be determined by cryptocompare by converting GBP to ETH.

Potential extensions
Integrate a governance / voting system which can dynamically add claiming methods.

For commit history see previous repo: https://github.com/willjgriff/hackathon-break-the-block/commits/master