Health-Ledger-Network

Contains scripts to run pre configured docker images for health ledger and create users to interact with the underlying hyperledger network.

Hyperledger Fabric

To run the hyperledger network locally please install docker and docker-compose.

Start

Starts the hyperledger network, installs genesis block and channel configuration.

$ cd hyperledger
$ ./start.sh

Stop

Stops the docker containers but preserves state.

$ cd hyperledger
$ ./stop.sh

Teardown

Stop and removes the docker containers.

$ cd hyperledger
$ ./teardown.sh

Network Structure

The health-ledger network is reachable on health-ledger.westeurope.cloudapp.azure.com and consists of following Nodes.

• Peer 0 - port :7051 / EventHub :7053
• Orderer - port :7050

To simplify the interaction with the network, there is a client wrapper (ledgerclient.js) in the deploy-chaincode subfolder and several scripts to demonstrate the usage. See also section Chaincode deployment for further information.

Certificates

For the interaction with the hyperledger network, each user needs a private key and a corresponding certificate signed by an hyperledger peer certificate authority.

The health-ledger network consists of the organizations health-ledger.de and mainorg.health-ledger.de. The latter one authorizes all peers and health-ledger users, while the first one is reserved for the orderer. The private.key and cert.pem file in the subfolders ca are the root certificates and will be used to sign new participants for the network. The Fabric Framework requires a private key generated with the elliptic curve algorithm.

New user workflow

In order to create new keys and certificates, signed by the mainorg.health-ledger.de organization, we can leverage the openssl command line tool.

• openssl ecparam -name prime256v1 -genkey -out private.key

  generates the private key for the new user and uses the prime256v1 elliptic curve algorithm.

• openssl req -new -key private.key -sha256 -out cert.csr

  starts an interactive command line to fill in the user information and outputs a certificate signing request. This request has now to be signed by certificate authority. Be sure to include the role (Patient, Arzt, etc..) of the user in the organization unit (OU) of the signing request.

• openssl ca -keyfile ca-private.key -cert ca-cert.pem -in cert.csr -out cert.pem -md sha256

  signs the request with the private key and certificate of the mainorg.health-ledger.de certificate authority.

To automate this workflow there is a newuser.sh bash script in the scripts subfolder of this repository. Just pass a filename for the private key and certifate as the first argument and follow the steps.

Cems-MBP-5:scripts cem$ ./newuser.sh user1
Generating a 256 bit EC private key
writing new private key to 'user1.key'
-----
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Land [DE]:
Bundesland [NRW]:
Stadt [Bielefeld]:
Organization [mainorg.health-ledger.de]:
Patient, Arzt, Versicherung, Apotheke, Arbeitgeber [Patient]:Versicherung
Benutzername [Cem Basoglu]:Hans Müller
Using configuration from openssl.cnf
Check that the request matches the signature
Signature ok
The Subject's Distinguished Name is as follows
countryName           :PRINTABLE:'DE'
stateOrProvinceName   :ASN.1 12:'NRW'
localityName          :ASN.1 12:'Bielefeld'
organizationName      :ASN.1 12:'mainorg.health-ledger.de'
organizationalUnitName:ASN.1 12:'Versicherung'
commonName            :ASN.1 12:'Hans Müller'
Certificate is to be certified until May  6 00:03:19 2118 GMT (36500 days)
Sign the certificate? [y/n]:y


1 out of 1 certificate requests certified, commit? [y/n]y

Chaincode deployment

For the deployment of chaincodes to health-ledger network, the nodejs scripts in the folder deploy-chaincode can be used.

The scripts are configured to connect to the Azure hosted network. If you want to use them on your local or other network, see section Ledger Client.

Usage

node deploy.js <path> <chaincodeId> [version] [type]

• path - mandatory: relative or full path to the folder, containing the chaincode script
• chaincodeId - mandatory: unique id used to deploy and later to interact with on the network
• version - optional: the version of the chaincode defaults to v1
• type - optional: chaincode type defaults to node

Example

Cems-MBP-5:deploy-chaincode cem$ node deploy.js ../testchaincode/ fabcar
info: [packager/Node.js]: packaging Node Chaincode from ../testchaincode/
{ success: true,
  txId:
   TransactionID {
     _nonce: <Buffer 16 37 6e 7d d0 6f e8 18 51 bb dd df 1a 6d 8a f4 82 8a d1 cc 77 e8 6c fb>,
     _transaction_id: 'e46e70d8558c477cb670cf20782163ad246a7f0ce5c8c67312904fc03951c0f9',
     _admin: true },
  install:
   [ [ [Object] ],
     { header: [ByteBuffer],
       payload: [ByteBuffer],
       extension: [ByteBuffer] } ],
  proposals:
   [ [ [Object] ],
     { header: [ByteBuffer],
       payload: [ByteBuffer],
       extension: [ByteBuffer] } ],
  transaction: { status: 'SUCCESS', info: '' } }

Ledger Client

In order to simplify the interaction with the Hyperledger peers and orderers, the ledgerclient.js script in the folder deploy-chaincode wraps the fabric-client functionality and provides a simplified application interface.

Configuration

The LedgerClient class is instantiated by passing a configuration object to the constructor. The configuration contains information of the signing user and optionally an admin, the network endpoints and the channel. Each instance of the LedgerClient is bound to this configuration, so for the usage in a multi session environment like a REST-API, you need a new intance for each requesting user.

The admin identity is only required for administrative tasks like deploying and instantiating chaincodes or modifying channel configurations.

var config = {
   channel: "mychannel",
   orderers: [
      "grpc://localhost:7050"
   ],
   peers: [
      "grpc://localhost:7051"
   ],
   hubs: [
      "grpc://localhost:7053"
   ],
   identity: {
      username: "user1",
      mspid: "MainOrgMSP",
      key: "-----BEGIN PRIVATE KEY-----\n .... \n-----END PRIVATE KEY-----",
      cert: "-----BEGIN CERTIFICATE-----\n .... \n-----END CERTIFICATE-----"
   }
   adminIdentity: {
      mspid: "MainOrgMSP",
      key: "-----BEGIN PRIVATE KEY-----\n .... \n-----END PRIVATE KEY-----",
      cert: "-----BEGIN CERTIFICATE-----\n .... \n-----END CERTIFICATE-----"
   }
}

Usage

const LedgerClient = require('./ledgerclient.js')

var config = { } //see section configuration

...
async function doSomething() {
  var client = new LedgerClient(config);
  await client.initFromConfig();
  
  try {
    let response = await client.queryByChaincode('fabcar', 'queryAllCars');
    console.log(response);
  }
  catch(e){
    console.log(e);
  }
}

API Reference

• constructor(config) - creates a new LedgerClient instance with the given configuration.

  Parameters:

  • config - See configuration for further information.

  Returns:

• initFromConfig() - the intialization of the client happens asynchronsly, this method has to be called after instantiation.

  Parameters:

  Returns: Promise - handler for async action

• newTransactionID(admin=false) - creates a new transaction id to use with transaction proposals.

  Parameters:

  • admin- should the transaction id created by the admin or user identity

  Returns: TransactionId - object with transaction id and originating identity