Real Estate Marketplace

This project involves using ERC721 non-fungible tokens (NFT) to represent Real Estate assets. Zero knowledge proofs (zk-snarks) are used to ensure that only an owner is able to mint tokens for a Real Estate asset. Assets are listed on OpenSea marketplace testnet on the Rinkeby network.

Contract ABI:

• To generate the contract abi run truffle compile
• The contract ABI can be found in eth-contracts/build/contracts/SolnSquareVerifier.json

Contract Address:

• 0x7f734b5a215cdb6fa76a176816820a9480fb212f
• View history on etherscan: https://rinkeby.etherscan.io/address/0x7f734b5a215cdb6fa76a176816820a9480fb212f

Token ID (number on the left) and Tx (on the right) for Tokens minted:

1. 0xe00a0dd757f43a4151e2ac380ae7925a98deca5320b6d69445fb245b4fcd714c
2. 0xaf738da4665b2dbed11a90a4e08f4443f3796c1c394e8983138eb092098b4f84
3. 0xc042a7fc979ea80721efc950e1a553976343d2978b025a67295dbb8525384189
4. 0x92aa088051caeb530d3227d8c64659d073a93f214cafd4bcf410dcf69f115a4c
5. 0x3d14b1a574a0fd90a4ab47f6a4c6fc05bb584285deea3506b58afc9063aff5e3
6. 0xfbe41b54c2ef462cccb205d1977deaa9b2927bfe629b09ccd199ede37aaa5b56
7. 0x3d0b902933285131de3d0b4214d7cee8590c1cfe89b077a1842992bc63872d31
8. 0xa3de7056b3d09292bee9e20f24ca5eeea8d0905aa8faba21bddd02ef573c9258
9. 0x59392f6e9fb6e841eef6f090a2edbbc3a2925b2a70ae16bc8b6c60b4f4624dd7
10. 0xb2b0bc10a370e734ab0b3e58dc730b8de582a9f6b7db658451981e46043d0889

Opensea marketplace storefront

My Contract storefront

Token Transfer Tx's

1. https://rinkeby.etherscan.io/tx/0x1b1f29961c0ba7c3b88e74604a580f503bf8a753ea17f5f2e5fc09b032be1f73
2. https://rinkeby.etherscan.io/tx/0xb0acbe89d3731b8f8bedbe4671407645a0573fac6fcd9104ed727a077c5dd1ff
3. https://rinkeby.etherscan.io/tx/0xc38caeb5ce18999135ee913a7973d200d13aeccbece9c759a6c31e655f0be755
4. https://rinkeby.etherscan.io/tx/0xde5092773622b109176b1d645ec58e97f53a6586b9d4878ac52846941c528fe0
5. https://rinkeby.etherscan.io/tx/0x507301dd0fd8b40e8e152e9cc5b7246f894206447043e393661e933f66fdacfd

Running the tests

Prerequisites

• Ensure ganache-cli, or ganache-gui (if using ganache-gui, you would need to change the port in truffle-config.js to 7545).
• Ensure truffle (specifically version 5.4.9 to avoid versioning issues) is installed.

To Run the tests

1. Install dependencies

# install all modules listed as dependencies in package.json
npm install

2. Start Ganache-cli

# Start Ganache cli local Ethereum
ganache-cli

3. Executing the test scripts

# This should compile the contracts, migrate then and execute the relevant tests for the project.
truffle test

Minting the tokens

1. Start Zokrates in Docker and generate a unique proof.json

zokrates compute-witness -a a b
# a and b are arguments for the proof function

zokrates generate-proof
# This generates the proof.json. You need to provide this in order to mintTokens

2. Start truffle console on the rinkeby network

truffle console --network rinkeby

3. Migrate the contracts (IF YOU HAVE NOT DONE THIS ALREADY)

> migrate

4. Get contract and proof an execute the mint command

> let tokenProof = require("../path/to/proof.json")
> let contract = await SolnSquareVerifier.deployed()
> contract.mintToken("address to mint to" , tokenIdNumber, tokenProof.proof.a, tokenProof.proof.b, tokenProof.proof.c, tokenProof.inputs)

Project Resources

• Remix - Solidity IDE
• Visual Studio Code
• Truffle Framework
• Ganache - One Click Blockchain
• Open Zeppelin
• Interactive zero knowledge 3-colorability demonstration
• Docker
• ZoKrates
• Helpful video