Blockchain for health record tracking

Based on Ethereum, IPFS, MetaMask and MyEtherWallet. MINGW64 environment.

This repo shows the basics of blockchains and IPFS integration. It lacks of security features, register encryption and IPFS' CID encryption. A consistent API should be developed. The implemented contract allows a medic to upload a health record's IPFS ID and a patient to download it, using the decentralized server to retrieve the file.

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References

Blockchain testing with Truffle and Ganache

• https://www.trufflesuite.com/docs/truffle/getting-started/installation
• https://www.trufflesuite.com/ganache
• https://www.trufflesuite.com/tutorials/configuring-visual-studio-code

Solidity docs (contracts)

• https://docs.soliditylang.org/en/v0.5.3/assembly.html

IPFS docs

• https://docs.ipfs.io/

Other references

• https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6764776/
• https://www.researchgate.net/publication/346581282_A_Blockchain_based_solution_for_Managing_Transplant_Waiting_Lists_and_Medical_Records

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Setup Truffle

Truffle install (requires Node.js)

npm install -g truffle

Project init in current directory

truffle init

Install Ganache GUI and start the workspace on Truffle's project directory.

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Private Server in IPFS

Install IPFS (GUI is also available. Used GUI on Windows and CLI on Linux)

sudo snap install ipfs

Check version (mine is in 0.7.0)

ipfs version

Init config

ipfs init

Generate random swarm key (swarm ID). Only nodes with this ID can connect to the swarm / network, so we need to copy this file on every node.

echo -e "/key/swarm/psk/1.0.0/\n/base16/\n`tr -dc 'a-f0-9' < /dev/urandom | head -c64`" > ~/.ipfs/swarm.key

Remove bootstrap nodes and check it's null. A bootstrap node is a peer node that also connects clients to other nodes of the network. We want to manually define them.

ipfs bootstrap rm --all
ipfs config show

Get node ID of bootstrap node

ipfs config show | grep "PeerID"

Example: 12D3KooWLQFyJEBs3MG26tumCDFcE6AAAZpreDoAN9e581mDs11c

Get IP of bootstrap node with ipconfig on Windows or netsat -rn on Linux, for a local network. On Virtual Box, typical IP's are 192.168.56.1 and 10.0.2.2. Check with ping on both systems.

Add bootstrap node on every machine, including the bootstrap node itself (remove with rm instead of add or rm --all).

ipfs bootstrap add /ip4/<ip>/tcp/4001/ipfs/<peer id hash>

Example: ipfs bootstrap add /ip4/192.168.56.1/tcp/4001/ipfs/12D3KooWLQFyJEBlertPNtumCDFE1a6e8F4eDoAN9eJ581mDs11c

Start IPFS

ipfs daemon

Check connection to peer

ipfs swarm peers
ipfs ping /ip4/<ip>/tcp/4001/ipfs/<peer id hash>

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Working with files in IPFS

Add file (returns hash)

echo "Hola Mundo!" > test.txt
ipfs add test.txt

Output file

ipfs cat <hash>

Example: ipfs cat QmbAYbAss5d8PJaCK4CKMZXBxvRghMCA7iuc43NWxpyuYT

Save file

ipfs cat QmbAYbAss5d8PJaC94CK4CXBxvRghMCA7iuc43NWxpyuYT > test.txt

Check bandwidth use

ipfs stats bw

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Truffle & Ganache

Test contract

In truffle directory, create a contract

truffle create contract HelloWorld

Open HelloWorld.sol file created in contracts and write ni function hi()

pragma solidity >=0.4.22 <0.8.0;

contract HelloWorld {
    constructor() public {
    }

    function hi() public pure returns (string memory) {
        return ("Hola");
    }
}

Compile contract

truffle compile

Create a 2_deploy_hello_contract.js file in migrations folder for deploying contract

var HelloWorld = artifacts.require("./HelloWorld.sol");

module.exports = function (deployer) {
    deployer.deploy(HelloWorld);
};

Launch Ganache and get the RPC SERVER address, port and network_id. Now, edit truffle-config.js file in truffle folder, uncommenting and editing the following lines, replacing data with your Ganache's data

networks: {
    development: {
        host: "127.0.0.1",
        port: 7545,
        network_id: 5777,
    }

Deploy your contracts

truffle migrate

Open console

truffle console

On console (should display truffle(development)>) test your contract

HelloWorld.deployed().then(function(contractInstance){contractInstance.hi().then(function(v){console.log(v)})})

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Healthcare test using MyEtherWallet

Create new contract

truffle create contract HealthRecord

Add some code in HealthRecord.sol where uploadRecord() allows medics to upload some record's IPFS ID in recordHash and the patient's blockchain address in patient

pragma solidity >=0.4.22 <0.8.0;

contract HealthRecord {
    address private patient;
    string private recordHash;
    bool private seen;

    constructor() public {}

    function uploadRecord(  string memory inputHash, 
                            address inputPatient) 
                            public returns(bool) {
        recordHash = inputHash;
        patient = inputPatient;
        seen = false;
        return true;
    }

    function getRecordHash() public view returns (string memory) {
        require(msg.sender == patient, "Invalid address.");
        return recordHash;
    }
}

Deploy contract

truffle migrate

Install MetaMask at https://metamask.io/ for your internet browser.

Add local blockchain to Metamask. Usual URL on Virtual Box is http://10.0.2.2:7545.

Import Ganache accounts to metamask using private keys.

Login to https://www.myetherwallet.com/ using MetaMask

Under contracts section, select your contract using the contract's blockchain address and your contract's ABI info available in the HealthRecord.json file under the build folder. Input the patient's address and health record's IPFS ID

Now in the patient's computer (Ubuntu), download the file using the same contract. Be sure to be logged in patient's account.

Start IPFS client with ipfs daemon on terminal

Download your health record with ipfs cat <IPFS CID> where IPFS CID is the ID the patient downloaded from MyEtherWallet.