Udacity Blockchain Capstone

This is a Blockchain based project. It covers NFT token and Zero Knowledge proof integration on blockchain. This project explaines how a conventional paper based property buying/selling can be implemented on Blockchain. Using Zokrates property ownership is verified without revealing any information about the owner of the property. After the zkSnarks or zero knowledge proof, the owner can mint the token i.e convert his property to NFT and thus can sale the minted token on OpenSea crypto market.

Install

Checkout the project. cd project folder and install required packages by running following command. Project assumes you have installed Truffle package globally.

npm i

npm i truffle-hdwallet-provider --save-dev

Testing Contracts

To test contracts, follow these commands:

cd <project-folder>/eth-contracts

truffle develop

test ./test/TestERC721Mintable.js

test ./test/TestSolnSquareVerifier.js

test ./test/TestSquareVerifier.js

Contract Addresses

Verifier.sol

0x78928071a1073e0D75e161eB349f03dBE7C52407

SolnSquareVerifier.sol

0x83d25985E4C9E9e8b7d2E273D45CeAee2Ce8E3b3

Contract Abi's

Verifier.sol

[
    {
      "constant": true,
      "inputs": [
        {
          "internalType": "uint256[2]",
          "name": "a",
          "type": "uint256[2]"
        },
        {
          "internalType": "uint256[2][2]",
          "name": "b",
          "type": "uint256[2][2]"
        },
        {
          "internalType": "uint256[2]",
          "name": "c",
          "type": "uint256[2]"
        },
        {
          "internalType": "uint256[2]",
          "name": "input",
          "type": "uint256[2]"
        }
      ],
      "name": "verifyTx",
      "outputs": [
        {
          "internalType": "bool",
          "name": "r",
          "type": "bool"
        }
      ],
      "payable": false,
      "stateMutability": "view",
      "type": "function"
    }
  ]

SolnSquareVerifier.sol

[
  {
    "inputs": [
      {
        "internalType": "address",
        "name": "verifierContractAddress",
        "type": "address"
      }
    ],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "constructor"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "owner",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "approved",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "Approval",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "owner",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "operator",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "bool",
        "name": "approved",
        "type": "bool"
      }
    ],
    "name": "ApprovalForAll",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": false,
        "internalType": "address",
        "name": "pauser",
        "type": "address"
      }
    ],
    "name": "Pause",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": false,
        "internalType": "address",
        "name": "solutioner",
        "type": "address"
      },
      {
        "indexed": false,
        "internalType": "uint256",
        "name": "index",
        "type": "uint256"
      }
    ],
    "name": "SolutionAdded",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "Transfer",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": true,
        "internalType": "address",
        "name": "oldOwner",
        "type": "address"
      },
      {
        "indexed": true,
        "internalType": "address",
        "name": "newOwner",
        "type": "address"
      }
    ],
    "name": "TransferOwnership",
    "type": "event"
  },
  {
    "anonymous": false,
    "inputs": [
      {
        "indexed": false,
        "internalType": "address",
        "name": "unpauser",
        "type": "address"
      }
    ],
    "name": "Unpause",
    "type": "event"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "bytes32",
        "name": "_myid",
        "type": "bytes32"
      },
      {
        "internalType": "string",
        "name": "_result",
        "type": "string"
      }
    ],
    "name": "__callback",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "bytes32",
        "name": "_myid",
        "type": "bytes32"
      },
      {
        "internalType": "string",
        "name": "_result",
        "type": "string"
      },
      {
        "internalType": "bytes",
        "name": "_proof",
        "type": "bytes"
      }
    ],
    "name": "__callback",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "approve",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "address",
        "name": "owner",
        "type": "address"
      }
    ],
    "name": "balanceOf",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [],
    "name": "baseTokenURI",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "getApproved",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [],
    "name": "getOwner",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "address",
        "name": "owner",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "operator",
        "type": "address"
      }
    ],
    "name": "isApprovedForAll",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "mint",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [],
    "name": "name",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "ownerOf",
    "outputs": [
      {
        "internalType": "address",
        "name": "",
        "type": "address"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [],
    "name": "pause",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "safeTransferFrom",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      },
      {
        "internalType": "bytes",
        "name": "_data",
        "type": "bytes"
      }
    ],
    "name": "safeTransferFrom",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "bool",
        "name": "approved",
        "type": "bool"
      }
    ],
    "name": "setApprovalForAll",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "bytes4",
        "name": "interfaceId",
        "type": "bytes4"
      }
    ],
    "name": "supportsInterface",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [],
    "name": "symbol",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "uint256",
        "name": "index",
        "type": "uint256"
      }
    ],
    "name": "tokenByIndex",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "address",
        "name": "owner",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "index",
        "type": "uint256"
      }
    ],
    "name": "tokenOfOwnerByIndex",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "tokenURI",
    "outputs": [
      {
        "internalType": "string",
        "name": "",
        "type": "string"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": true,
    "inputs": [],
    "name": "totalSupply",
    "outputs": [
      {
        "internalType": "uint256",
        "name": "",
        "type": "uint256"
      }
    ],
    "payable": false,
    "stateMutability": "view",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "from",
        "type": "address"
      },
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "transferFrom",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "newOwner",
        "type": "address"
      }
    ],
    "name": "transferOwnership",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [],
    "name": "unpause",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "addr",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "index",
        "type": "uint256"
      },
      {
        "internalType": "uint256[2]",
        "name": "a",
        "type": "uint256[2]"
      },
      {
        "internalType": "uint256[2][2]",
        "name": "b",
        "type": "uint256[2][2]"
      },
      {
        "internalType": "uint256[2]",
        "name": "c",
        "type": "uint256[2]"
      },
      {
        "internalType": "uint256[2]",
        "name": "input",
        "type": "uint256[2]"
      }
    ],
    "name": "addSolution",
    "outputs": [],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  },
  {
    "constant": false,
    "inputs": [
      {
        "internalType": "address",
        "name": "to",
        "type": "address"
      },
      {
        "internalType": "uint256",
        "name": "tokenId",
        "type": "uint256"
      }
    ],
    "name": "mintNFT",
    "outputs": [
      {
        "internalType": "bool",
        "name": "",
        "type": "bool"
      }
    ],
    "payable": false,
    "stateMutability": "nonpayable",
    "type": "function"
  }
]