Proof of Existence (Ethereum)

Setup

node version:

node -v
v12.16.3

Install project dependencies

yarn install

Shell 1 - Launch an ethereum test chain (Hardhat)

yarn chain

Shell 2 - Start web client UI and connect to chain (scaffold-eth)

yarn start

Shell 3 - Deploy smart contract to chain (Solidity)

yarn deploy

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Smart Registration

http://localhost:3000/

When the browser loads, you will be introduced to an instance of scaffold-eth that provides you with a wallet and account so that you can interact with the Ethereum deployed Land Registry Smart Contract via your account.

• By default your account is the owner of the contract, and assumes the role of the Registrar.
• Alternative accounts (citizens) can be generated using another browser (incognito).

Grab some Gas

Before you begin, you need to fund your account with some gas. Almost all transaction calls incur gas.

• In the top right of your screen select 'Grab funds from the faucet'

Scenarios

Note: For the following scenarios the 'title' is the string representation of the title data, ie the JSON object for registration.

Register a proof

As a registrar

• enter the title ATITLE in the proofOfExistance box
• click send
• Registrar is notified by an exception 'this proof is NOT registered'.

As a registrar

• enter the title ATITLE in the registerExistance box
• click send
• Everyone is notified his address 'has registered this proof'.

As a registrar

• enter the title ATITLE in the registerExistance box
• click send
• Everyone is notified that this proof exists.

Citizen query a proof (Incognito browser)

As a citizen

• enter the title BTITLE in the proofOfExistance box
• click send
• citizen is notified by an exception 'this proof is NOT registered'.

As a citizen

• enter the title ATITLE in the proofOfExistance box
• click send
• Everyone is notified his address 'has registered this proof'.

Role Based services

The smart contract is Ownable meaning it is owned by the deploying account (Registrar)

• Role: Registrar
  • Only the Registrar can register proofs
  • The Registrar can transfer the ownership of the contract to another address ie another Registrar
  • The Registrar can renounce ownership of the contract meaning it will noo longer accept registrations.
• Role: Citizen
  • The citizen can only request the proofOfExistance service.
  • Access to all other methods is restricted to the owner of the contract.

Future Improvements

There is an opportunity to introduce decentralised filestorage for the documnent that the proof represents and then render a link to that document on proof of existance. A content addressed storage such as IPFS or filecoin would be a good fit.

It would be better to have IPFS generate the hash of the content off chain, since all calls on chain incur gas.

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Credits

🙏 This project is a fork of scaffold-eth, a rapid feedback etheruem SDK (https://github.com/austintgriffith/scaffold-eth.git)