This project is about managing Real Estate Marketplace in Etherium Blockchain. Each property is represented by ERC721 Token. before you can mint a token you need to verify that you are the owner of the property. zk-SNARKs is used to create a verification system which can prove you have title to the property without revealing that specific information on the property.Once the token has been verified you will place it on a blockchain market place (OpenSea) for others to purchase.
Versions
- Truffle : v5.4.26
- Node : v16.13.2
- Web3.js : v1.5.3
- zokrates/zokrates : 1.0.43
To install, download or clone the repo, then:
npm install
To compile go under eth-contracts folder then execute :
truffle compile
To run truffle tests:
ganache-cli -l 10000000000- In another Terminal :
cd eth-contracts && truffle test --network development
Starting migrations...
======================
> Network name: 'rinkeby'
> Network id: 4
> Block gas limit: 29999972 (0x1c9c364)
1_initial_migration.js
======================
Replacing 'Migrations'
----------------------
> transaction hash: 0x3757ac417534832d9297932cd2256f08f28990cc94102d84ff2c30b9e3c1135d
> Blocks: 1 Seconds: 14
> contract address: 0xC632F1710667a84101a4c237A36173C04C3092b1
> block number: 10668757
> block timestamp: 1652443370
> account: 0xD10DA32e7560Ef650dAbB392289C48bEA37AcD45
> balance: 0.14205782
> gas used: 274520 (0x43058)
> gas price: 10 gwei
> value sent: 0 ETH
> total cost: 0.0027452 ETH
> Saving migration to chain.
> Saving artifacts
-------------------------------------
> Total cost: 0.0027452 ETH
2_deploy_contracts.js
=====================
Deploying 'Verifier'
--------------------
> transaction hash: 0xd045604d8fbaa256b057980649d3673bd2cffb590278daadc52327f3856a8efe
> Blocks: 2 Seconds: 22
> contract address: 0x81050066f14230b25D615E4FADAd98e02A911604
> block number: 10668760
> block timestamp: 1652443415
> account: 0xD10DA32e7560Ef650dAbB392289C48bEA37AcD45
> balance: 0.12960792
> gas used: 1199052 (0x124bcc)
> gas price: 10 gwei
> value sent: 0 ETH
> total cost: 0.01199052 ETH
Replacing 'SolnSquareVerifier'
------------------------------
> transaction hash: 0x083c7a323de6ffc957fb065e134e2679ed4632908199d889f134ea939ddd11fe
> Blocks: 1 Seconds: 6
> contract address: 0x5A746a757dD183c648cfb7619307C3f46c5a55F6
> block number: 10668761
> block timestamp: 1652443430
> account: 0xD10DA32e7560Ef650dAbB392289C48bEA37AcD45
> balance: 0.09293595
> gas used: 3667197 (0x37f4fd)
> gas price: 10 gwei
> value sent: 0 ETH
> total cost: 0.03667197 ETH
> Saving migration to chain.
> Saving artifacts
-------------------------------------
> Total cost: 0.04866249 ETH
A simple NodeJS script has been used to mint the 10 tokens.
truffle exec scripts\mint.js --network rinkeby
Using network 'rinkeby'.
Token minted, index: 1
tx: 0x9ffaa98d509d5c1e69c8d8e3492a1c0ba9b5c4eabbc9b9e7278ff5e1e672a7ef
Token minted, index: 2
tx: 0xa2c79ac2d03c0feb10e70ac47d6d9958c9f6a74352034831d9d503fd74b8fd2c
Token minted, index: 3
tx: 0x4a08d7dcd32ec7e982e62c16193c729a04356eee87b63431c5e02c1ba1f288a0
Token minted, index: 4
tx: 0xb41246c28321ee8450453bd632f9a1ac77b9abc2a50613ca9eeac485e9d20c9c
Token minted, index: 5
tx: 0x88a3cf75e02eb1fa9b93a2e7feb51eefd4018408c4f1403bdc5003bca2309528
Token minted, index: 6
tx: 0x65042dd1a5f55fafb6a47e5f2dfac66f6cb83d9dbf4558ea4fda7181818a3fc2
Tokens successfully minted
https://testnets.opensea.io/collection/realestatetokenz
The NFTs have been traded between sample accounts and the activiy can be found in the screenshot below.
[
{
"inputs": [
{
"internalType": "address",
"name": "_verifierContractAddress",
"type": "address"
}
],
"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": "newOwner",
"type": "address"
}
],
"name": "OwnerShipTransfer",
"type": "event"
},
{
"anonymous": false,
"inputs": [
{
"indexed": false,
"internalType": "address",
"name": "triggerAddress",
"type": "address"
}
],
"name": "Paused",
"type": "event"
},
{
"anonymous": false,
"inputs": [
{
"indexed": false,
"internalType": "bytes32",
"name": "key",
"type": "bytes32"
},
{
"indexed": false,
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
},
{
"indexed": false,
"internalType": "address",
"name": "user",
"type": "address"
}
],
"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": false,
"internalType": "address",
"name": "triggerAddress",
"type": "address"
}
],
"name": "Unpaused",
"type": "event"
},
{
"inputs": [
{
"internalType": "bytes32",
"name": "_myid",
"type": "bytes32"
},
{
"internalType": "string",
"name": "_result",
"type": "string"
}
],
"name": "__callback",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "bytes32",
"name": "_myid",
"type": "bytes32"
},
{
"internalType": "string",
"name": "_result",
"type": "string"
},
{
"internalType": "bytes",
"name": "_proof",
"type": "bytes"
}
],
"name": "__callback",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "address",
"name": "to",
"type": "address"
},
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "approve",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "address",
"name": "owner",
"type": "address"
}
],
"name": "balanceOf",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [],
"name": "baseTokenUri",
"outputs": [
{
"internalType": "string",
"name": "",
"type": "string"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "getApproved",
"outputs": [
{
"internalType": "address",
"name": "",
"type": "address"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [],
"name": "getOwner",
"outputs": [
{
"internalType": "address",
"name": "",
"type": "address"
}
],
"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"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "address",
"name": "to",
"type": "address"
},
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "mint",
"outputs": [
{
"internalType": "bool",
"name": "",
"type": "bool"
}
],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [],
"name": "name",
"outputs": [
{
"internalType": "string",
"name": "",
"type": "string"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "ownerOf",
"outputs": [
{
"internalType": "address",
"name": "",
"type": "address"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "address",
"name": "from",
"type": "address"
},
{
"internalType": "address",
"name": "to",
"type": "address"
},
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "safeTransferFrom",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"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": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "address",
"name": "to",
"type": "address"
},
{
"internalType": "bool",
"name": "approved",
"type": "bool"
}
],
"name": "setApprovalForAll",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "bool",
"name": "state",
"type": "bool"
}
],
"name": "setPaused",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "bytes4",
"name": "interfaceId",
"type": "bytes4"
}
],
"name": "supportsInterface",
"outputs": [
{
"internalType": "bool",
"name": "",
"type": "bool"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [],
"name": "symbol",
"outputs": [
{
"internalType": "string",
"name": "",
"type": "string"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "uint256",
"name": "index",
"type": "uint256"
}
],
"name": "tokenByIndex",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"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"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "tokenURI",
"outputs": [
{
"internalType": "string",
"name": "",
"type": "string"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [],
"name": "totalSupply",
"outputs": [
{
"internalType": "uint256",
"name": "",
"type": "uint256"
}
],
"stateMutability": "view",
"type": "function",
"constant": true
},
{
"inputs": [
{
"internalType": "address",
"name": "from",
"type": "address"
},
{
"internalType": "address",
"name": "to",
"type": "address"
},
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "transferFrom",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "address",
"name": "newOwner",
"type": "address"
}
],
"name": "transferOwnership",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"internalType": "address",
"name": "user",
"type": "address"
},
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
},
{
"internalType": "uint256[2]",
"name": "input",
"type": "uint256[2]"
}
],
"name": "addSolution",
"outputs": [],
"stateMutability": "nonpayable",
"type": "function"
},
{
"inputs": [
{
"components": [
{
"components": [
{
"internalType": "uint256",
"name": "X",
"type": "uint256"
},
{
"internalType": "uint256",
"name": "Y",
"type": "uint256"
}
],
"internalType": "struct Pairing.G1Point",
"name": "a",
"type": "tuple"
},
{
"components": [
{
"internalType": "uint256[2]",
"name": "X",
"type": "uint256[2]"
},
{
"internalType": "uint256[2]",
"name": "Y",
"type": "uint256[2]"
}
],
"internalType": "struct Pairing.G2Point",
"name": "b",
"type": "tuple"
},
{
"components": [
{
"internalType": "uint256",
"name": "X",
"type": "uint256"
},
{
"internalType": "uint256",
"name": "Y",
"type": "uint256"
}
],
"internalType": "struct Pairing.G1Point",
"name": "c",
"type": "tuple"
}
],
"internalType": "struct Verifier.Proof",
"name": "proof",
"type": "tuple"
},
{
"internalType": "uint256[2]",
"name": "input",
"type": "uint256[2]"
},
{
"internalType": "address",
"name": "user",
"type": "address"
},
{
"internalType": "uint256",
"name": "tokenId",
"type": "uint256"
}
],
"name": "mintNFT",
"outputs": [
{
"internalType": "bool",
"name": "",
"type": "bool"
}
],
"stateMutability": "nonpayable",
"type": "function"
}
]
ZoKrates is a toolbox for zkSNARKs on Ethereum. It helps you use verifiable computation in your DApp, from the specification of your program in a high level language to generating proofs of computation to verifying those proofs in Solidity.
- We will prove knowledge of the square root a of a number b:
./zokrates/code/square/square.code
def main(private field a, field b) -> (field):
field result = if a * a == b then 1 else 0 fi
return result
-
You can use the zokrates CLI from docker container :
docker run -v $PWD:/home/zokrates/code -ti zokrates/zokrates /bin/bash -
Then run the different phases of the protocol to generate the solidity verifier :
# compile
zokrates compile -i zokrates/code/square/square.code
# perform the setup phase
zokrates setup
# execute the program
zokrates compute-witness -a 3 9
# generate a proof of computation
zokrates generate-proof
# export a solidity verifier
zokrates export-verifier