docker-decentralized-identity

Overview

This is a project to explore the use case of decentralized identity with HyperLedger Indy.

Business case

I am an insurer with an insurance company. I went to the hospital for an op and receive the medical invoice. I take the medical invoice and make the claim to the insurance company.

Challenge

• How can the insurance verify the medical invoice without approaching the hospital?
• Is there a way to prevent tampering of the invoice in case of false claims?

Approach

I decided to use decentralized identity approach to tackle this problem because it do aways the need to have central authority to verify a record. A record in this context will be the policy with the insurance company, the medical invoice with the hospital.

And the underlying decentralized identity datastore is a distributed ledger, which make a record immutable, difficult to tamper.

The nature of distributed ledger also help to decentralize the verification process. Multiple parties in the distributed ledger can help to verify the record. In this context, when I file the medical claim, the existing records with the insurance company and hospital verify the claim behind the scene.

Challenges

After initial studies, I identified the key challenges as below:

• All examples in Hyperledger Indy are monolithic, it indicate the need to break down and translate into meaningful microservices.

• How can I make this project portable so someone else can easily deploy and try out.

Architecture Design

Microservices

I decided to approach this from the business perspective and identify what are the key RESTful API and develop microservices using ExpressJS. This will help to decouple the front-end application (yet to implement) and the business logic.

Distributed Ledger

To understand decentralized identity, HyperLedger Indy seem to be a popular choice. Therefore, I use that as the DL database to store the decentralized identities, credentials, schemas and credential definitions.

Further improvements

• Since there are microservices now, I can build a front-end application to manage activities like onboarding new party, search for a party and list its records in the digital wallet, revoke a record etc.

• Implement a NoSQL database to persist the verification keys. So one can easily retrieve them for verification.

• To scale, it will be good to introduce queues in front of each API endpoint, so this allow to regulate the flow or extend to other work flows.

• Tighten the API endpoint security with OAuth, JWT token.

• In general, take the solution to any cloud provider will be a great idea, there are a lot of managed services that help with infrastructure setup, scaling, security and resource management.

Prerequisites

• NodeJS, latest version
• NPM, latest version
• Docker desktop client, latest version

Techology Stack

1. NodeJS, latest version
2. ExpressJS, latest version
3. HyperLedger Indy, latest version
4. Docker, latest version

Initialization

We need to first run the docker container before testing.

1. At the project root folder level, run ./run.sh
2. Wait for run.sh to complete. Wait for API server listening on port 9000!

USE CASE 0 - Normal use case

1. Stop and run ./run.sh to flush and reset the docker container.
2. At api-server folder, run node tests 0

Results should look like this:

$ node tests 0
== USE CASE 0: NORMAL ==
Creating wallets for steward, insurance, hospital and insurer
Onboarding insurance with steward
Onboarding hospital with steward
Create a policy credential definition for insurance
Create a medical invoice credential definition for hospital
Onboard insurer for insurance
Onboard insurer for hospital
Insurer register for policy with insurance
Insurer get medical invoice from hospital
Insurer file medical claim to insurance

APPLICATION IS VERIFIED

USE CASE 1 - Missing medical invoice use case

1. Stop and run ./run.sh to flush and reset the docker container.
2. At api-server folder, run node tests 1

Results should look like this:

$ node tests 1
== USE CASE 1: MISSING MEDICAL CLAIM ==
Creating wallets for steward, insurance, hospital and insurer
Onboarding insurance with steward
Onboarding hospital with steward
Create a policy credential definition for insurance
Create a medical invoice credential definition for hospital
Onboard insurer for insurance
Onboard insurer for hospital
Insurer register for policy with insurance
Insurer file medical claim to insurance

UNABLE TO VERIFY THIS APPLICATION. REASON: UNABLE TO GET CREDENTIAL FOR INVOICENO

USE CASE 2 - Tampering proof use case

This use case is special as it involve tampering the created proof. See create-application.js:L139

1. Stop and run ./run.sh to flush and reset the docker container.
2. At api-server folder, run node tests 2

Results should look like this:

$ node tests 2
== USE CASE 2: MEDICAL CLAIM PROOF TAMPERING ==
Creating wallets for steward, insurance, hospital and insurer
Onboarding insurance with steward
Onboarding hospital with steward
Create a policy credential definition for insurance
Create a medical invoice credential definition for hospital
Onboard insurer for insurance
Onboard insurer for hospital
Insurer register for policy with insurance
Insurer get medical invoice from hospital
Insurer file medical claim to insurance


UNABLE TO VERIFY THIS APPLICATION. REASON: ANONCREDSPROOFREJECTED

##Troubleshooting

• In case the docker fail to connect to ledger pool, just re-run ./run.sh
• Alternatively, restart docker client helps too.

Attaching to docker-decentralized-identity_ledger_1, docker-decentralized-identity_api_1
ledger_1  | 2020-02-17 03:33:39,667 CRIT Set uid to user 1000
api_1     |
api_1     | > api-server@1.0.0 start /usr/src/app
api_1     | > node index.js
api_1     |
api_1     | Bootstrapping...
api_1     | Connected to indy_pool
api_1     | This will take a while, trying to open ledger pool...
api_1     | { IndyError: PoolLedgerTimeout
api_1     |     at Object.callback (/usr/src/app/node_modules/indy-sdk/src/wrapIndyCallback.js:15:10)
api_1     |   name: 'IndyError',
api_1     |   message: 'PoolLedgerTimeout',
api_1     |   indyCode: 307,
api_1     |   indyName: 'PoolLedgerTimeout',
api_1     |   indyCurrentErrorJson: null }
api_1     | (node:17) UnhandledPromiseRejectionWarning: IndyError: PoolLedgerTimeout
api_1     |     at Object.callback (/usr/src/app/node_modules/indy-sdk/src/wrapIndyCallback.js:15:10)