LIVE DEMO

Built with:

• Next.js
• TypeScript
• Hardhat
• TypeChain
• Ethers.js
• useDApp
• Chakra UI
• Moralis

Chainsign adds signing and verifying e-contract and document function to the blockchain. This solves legal issues involved with documents through use of chainlink and smart contracts

With blockchain, documents are embedded in digital code and stored in transparent, shared databases, where they’re protected from deletion, tampering and revision. Every agreement, every task, and every payment would have a digital record and signature that could be identified, validated, stored, and shared. Intermediaries like lawyers, brokers and institutions might no longer be necessary. Individuals and organizations would freely transact and interact with one another with little friction. This is the immense potential of blockchain.

Document upload flow

Certificates are issued by an authority, such as an education institute, legal institution stored oncentralized document management server, or on a distributed file system like IPFS and signed with a cryptographic function. The content hash and certificate’s metadata hash are then stored on the blockchain digital ledger and attached to the user’s digital identity as a smart contract address that stores this information This represents a sort of unique authenticity token, which identifies the document in a non-questionable way.

• Signer has to LogIn
• After LogIn has been successful you can upload a document.
• You can sign uploaded document.
• DocumentHash / Meta data hash is generated. DocumentHash should be stored on Blockchain. Signed document is stored on IPFS.

Document verification flow

Users who need to verify their certificates with a third party do so by sharing the authenticity token (that is, the file contract address), which contains all the necessary information to verify that the document exists and is authentic and not counterfeited.

The user retrieves the certificate to verify from its location and initiates a new transaction on the blockchain network, transferring the authenticity token to the verification authority. The authority obtains the signed content and metadata of the certificate being verified and then compares them with the equivalent hash values from the off-chain copy. If the values match, the document is verified End-to-end implementation of the following Chainlink features using Hardhat development environment and Next.js frontend framework:

Built with:

• Next.js
• TypeScript
• Hardhat
• TypeChain
• Ethers.js
• useDApp
• Chakra UI
• Linting with ESLint
• Formatting with Prettier

• Node
• Yarn
• Git

In order to use the frontend portion of the demo application you will need

• A crypto wallet such as Metamask or Coinbase Wallet
• Test $LINK for the relevant testnet. You can get some at the Chainlink Faucets page.
• Test $ETH to pay for gas costs. You can get some at the Chainlink Faucets page.

Clone the repo and install all dependencies:

git clone https://github.com/hackbg/chainlink-fullstack
cd chainlink-fullstack

git submodule init
git submodule update

yarn install

Start up the local Hardhat network and deploy all contracts:

yarn chain

In a second terminal start up the local development server run the front-end app:

yarn dev

To interact with the local network, follow this step-by-step guide on how to use MetaMask with a Hardhat node.

If you've set the mnemonic from MetaMask the first 20 accounts will be funded with ETH.

To make setting environment variables easier there are .env.example files in the hardhat and frontend workspaces. You can copy them to new .env files and replace the values with your own.

This will run the deploy scripts to a local Hardhat network:

yarn deploy

To deploy on a public network:

yarn deploy --network kovan

The Hardhat project will attempt to auto-fund any newly deployed contract that uses Any-API or VRF, which otherwise has to be done manually.

The amount in LINK to send as part of this process can be modified in this Hardhat Config, and are configurable per network.

If you wish to deploy the smart contracts without performing the auto-funding, run the following command when doing your deployment:

yarn deploy --tags main

If the test command is executed without a specified network it will run locally and only perform the unit tests:

yarn test:contracts

Integration tests must be run on a public testnet that has Chainlink oracles responding:

yarn test:contracts --network kovan

For coverage report:

yarn coverage:contracts

You'll need an ETHERSCAN_API_KEY environment variable. You can get one from the Etherscan API site.

npx hardhat verify --network <NETWORK> <CONTRACT_ADDRESS> <CONSTRUCTOR_PARAMETERS>

example:

npx hardhat verify --network kovan 0x9279791897f112a41FfDa267ff7DbBC46b96c296 "0x9326BFA02ADD2366b30bacB125260Af641031331"

Fix formatting according to prettier config in the respective workspace:

yarn format:frontend
yarn format:hardhat

yarn lint:frontend

This repo includes deployed and verified contracts on Kovan and Rinkeby so the front-end can run without the need to deploy them.

Once the deploy command is executed on any network the contracts config will be overwritten and you can start from scratch with your own deployments.

• Chainlink Docs
• Chainlink Hardhat Box
• Scaffold ETH