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RandomNumberRetailerSepolia.sol
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RandomNumberRetailerSepolia.sol
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// SPDX-License-Identifier: UNLICENSED
// ~~~~~~~~~~~~~~~Random Number Retailer: Random Numbers Just Got a Whole Lot Cheaper... And Easier Too!~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// | |
// | This program has two major aims: |
// | |
// | 1. Reduce the price of verifiably random numbers on chain when requested in small batches. |
// | |
// | As of 2/29/24, Chainlink VRF v2 charges a similar amount for anywhere between one and five hundred random numbers. |
// | This means that getting a single random number is about as expensive as getting five hundred random numbers! |
// | | |
// | This smart contract charges a set price per random number, making requests for small amounts of random numbers much cheaper. |
// | The price we charge per random number is determined by priceOfARandomNumberInWei. |
// | |
// | We will try to keep the price much lower for small batches of random numbers than if the caller purchased them from Chainlink VRF v2. |
// | Additionally, we accept ETH for the random numbers instead of LINK, which makes our contract way easier to use than Chainlink VRF v2 and saves the caller a ton of gas. |
// | For many applications, we expect the cost savings to be significant. |
// | |
// | 2. Convert Chainlink VRF v2 from async to sync, drastically improving its ease of use. |
// | |
// | By design, Chainlink VRF v2 is asynchronous: first, you make a transaction to the VRF v2 coordinator to request the random numbers. |
// | Then, some unknowable time in the future, Chainlink **might** call the callback method on your smart contract with the random numbers you've requested. |
// | This asynchronous design makes using verifiable randomness on the blockchain extremely awkward and cumbersome. |
// | |
// | This smart contract allows the caller to request random numbers in a completely synchronous fashion. |
// | The random numbers are returned instantly from this contract when requested, drastically improving on Chainlink's ease of use and flexibility. |
// | With this smart contract, there is no need for a callback method, and no need to wait for a second transaction. |
// | You will receive your random numbers immediately with no hassle. |
// | |
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// | |
// | Instructions for using this contract: |
// | |
// | 1. Begin by checking randomNumbersAvailable to see how many random numbers are available for purchase. |
// | Then, create a uint256 specifying how many random numbers you wish to buy. |
// | Let's call that amountOfRandomNumbersToRequest. |
// | Remember that other callers can buy random numbers during the same block, so it's possible the amount of random numbers you can buy is lower than randomNumbersAvailable. |
// | However, we constantly supply additional random numbers to this contract when randomNumbersAvailable goes below minimumHealthyLengthOfRandomNumbersArray. |
// | As long as this contract is active, it should usually have a healthy supply of random numbers available for purchase. |
// | |
// | 2. Next, multiply priceOfARandomNumberInWei by amountOfRandomNumbersToRequest. |
// | We'll call that totalPrice. |
// | This is the amount of ETH in wei that you must explicitly pay when requesting random numbers from this smart contract. |
// | |
// | 3. Generate an array of uint256 random seeds. Let's call it randomSeedArray. |
// | To maximize safety and randomness, you should ideally generate your random seeds off of the blockchain, in a traditional programming language. |
// | If the user is calling your smart contract in a web browser, you can use JavaScript to generate different random seeds for each call. |
// | If you are calling the smart contract from a server, you should generate the random seeds in your programming language of choice. |
// | It is possible to generate pseudorandom seeds on the blockchain, but it is not ideal. |
// | If your random seeds are too easily guessable, a validator or MEV bot could attack your smart contract. |
// | |
// | 4. Call requestRandomNumbersSynchronous(amountOfRandomNumbersToRequest, randomSeedArray) and set the value of the transaction to totalPrice. |
// | If the call succeeds, an array of verifiably random uint256 numbers will be returned. |
// | The length of the returned array will be equal to amountOfRandomNumbersToRequest. |
// | Now, you can use verifiably random numbers in your smart contract in an easy, affordable, and synchronous manner! |
// | |
// | Advanced users can call requestRandomNumbersSynchronousUsingVRFv2Seed instead to swap their Chainlink VRFv2 proof for our verifiably random numbers. |
// | |
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// | |
// | Future plans: |
// | |
// | 1. Deployment on other blockchains |
// | |
// | We are planning on deploying a version of this contract on all blockchains that support Chainlink VRF v2. |
// | Currently, that includes Ethereum, Arbitrum, Polygon (Matic), Avalanche, BNB Chain, and Fantom. |
// | We will also deploy contracts to each blockchain's respective testnets. |
// | We will try to keep the owner / deployer and server addresses consistent across blockchains so you can verify the legitimacy of the smart contracts. |
// | We may also deploy to additional blockchains as needed. |
// | |
// | 2. Token airdrop |
// | |
// | At some point, we plan on releasing an ERC20 token that rewards the use of our smart contracts. |
// | The more random numbers you've purchased from one of our smart contracts on a given blockchain, the larger the airdrop you'll receive on that blockchain. |
// | Testnets will not receive the airdrop. |
// | |
// | Tokens will be airdropped on all non-testnet blockchains that contain one of our smart contracts. |
// | The tokens should be able to flow seamlessly between all supported blockchains. |
// | |
// | These tokens are not securities and you should not expect us to try to increase their price. |
// | |
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// | |
// | Verifying the legitimacy of this smart contract: | |
// | The owner / deployer address is 0x8Fb9bcdde589059a87eE1056f5bc3F52782d55BB |
// | The server address is 0xD16512fdBb90096B1f1888Cae6152177065FdA62 |
// | |
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// | |
// | Legal: |
// | |
// | Random Number Retailer LLC Copyright 2024 |
// | Random Number Retailer LLC is a Limited Liability Company registered in the state of New Mexico, United States of America. |
// | |
// | Anyone who is not sanctioned by the United States of America is allowed to read the public variables of this smart contract. |
// | |
// | Anyone who is not sanctioned by the United States of America can call the following methods by submitting a transaction to the blockchain on which this smart contract resides: |
// | randomNumbersAvailable |
// | requestRandomNumbersSynchronous |
// | requestRandomNumbersSynchronousUsingVRFv2Seed |
// | |
// | Anyone processing transactions for the blockchain on which this smart contract resides can process any transaction associated with this smart contract in the standard manner. No special behavior is required. |
// | |
// | No person or entity other than Random Number Retailer LLC is allowed to call any method with the modifiers onlyServer or onlyOwner by submitting a transaction to the blockchain on which this smart contract resides without the explicit consent of Random Number Retailer LLC. |
// | |
// | The code for the "RandomNumberRetailer" contract is available to view publicly, but no party other than Random Number Retailer LLC can reuse any of this proprietary code in a separate smart contract or program of any sort without the explicit consent of Random Number Retailer LLC. |
// | |
// | Any person or entity who reuses any part of this code in a separate smart contract or program without the explicit consent of Random Number Retailer LLC may be subject to legal action. |
// | |
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
// | |
// | Contact: |
// | |
// | As of 2/29/24, Random Number Retailer LLC uses a gmail account for most correspondence. |
// | Please email randomnumberretailer@gmail.com with any proposals, feedback, etc. |
// | Keep up with our announcements on Twitter / X: https://twitter.com/RNRetailer or https://x.com/RNRetailer |
// | |
// ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
pragma solidity ^0.8.7;
import "@chainlink/contracts/src/v0.8/ConfirmedOwner.sol";
import "./VRF.sol";
import "@openzeppelin/contracts/utils/Create2.sol";
// BlockhashStoreInterface is from Chainlink
interface BlockhashStoreInterface {
function getBlockhash(uint256 number) external view returns (bytes32);
}
contract RandomNumberRetailer is VRF, ConfirmedOwner
{
uint256 public minimumHealthyLengthOfRandomNumbersArray = 5000;
uint256 public priceOfARandomNumberInWei = 439;
uint256 public minimumViablePriceOfARandomNumberInWei = 10;
uint256 public mostRecentRequestId = 0;
uint256 private mostRecentlyReturnedRandomNumber = 0;
uint256 private minimumServerBalanceInWei = 1000000000000000000;
uint256 private maximumCostOfSendInWei = 50000000000000000;
uint256 private amountOfGasUsedForAFulfillRandomNumbersTransaction = 11524416;
uint32 private maximumNumbersThatCanBeFulfilledInOneTransaction = 500;
address public replacementContractAddress = address(0);
bool public contractIsPaused = false;
uint8 public priceMultiplier = 5;
error BlockhashNotInStore(uint256 blockNum); // from Chainlink
BlockhashStoreInterface public constant BLOCKHASH_STORE = BlockhashStoreInterface(0x1159E1889754a1F0862F8EC0E109F169aECBCD6f); // from Chainlink
event RandomWordsFulfilled(uint256 indexed requestId, uint256 outputSeed, uint96 payment, bool success); // from Chainlink
event RandomWordsReturnedSync(address indexed requestor, uint256 weiPaid, uint256 amountOfRandomNumbersReturned);
address private constant ownerAddress = 0x8Fb9bcdde589059a87eE1056f5bc3F52782d55BB; // prod owner
//address private constant ownerAddress = 0x6D615F78382314B9Aa388975a51e20Cbc65Ae6b5; // test owner
address private constant serverAddress = 0xD16512fdBb90096B1f1888Cae6152177065FdA62;
struct RequestCommitment {
uint64 blockNum;
uint256 subId;
uint32 callbackGasLimit;
uint32 numWords;
address sender;
bytes extraArgs;
}
uint256[] private randomNumbersArray = new uint256[](0);
constructor()
ConfirmedOwner(ownerAddress)
{}
modifier onlyServer() {
require(
msg.sender == serverAddress,
"FAILURE: Only the server can call this method."
);
_;
}
modifier checkIfPaused() {
require(
!contractIsPaused,
"FAILURE: The contract is paused."
);
_;
}
modifier checkIfDeprecated(){
require(
replacementContractAddress == address(0),
"FAILURE: This contract is deprecated. Please check replacementContractAddress for the new contract address."
);
_;
}
function setMaximumNumbersThatCanBeFulfilledInOneTransaction(
uint32 _maximumNumbersThatCanBeFulfilledInOneTransaction
) external onlyOwner{
maximumNumbersThatCanBeFulfilledInOneTransaction = _maximumNumbersThatCanBeFulfilledInOneTransaction;
}
function setAmountOfGasUsedForAFulfillRandomNumbersTransaction(
uint256 _amountOfGasUsedForAFulfillRandomNumbersTransaction
) external onlyOwner{
amountOfGasUsedForAFulfillRandomNumbersTransaction = _amountOfGasUsedForAFulfillRandomNumbersTransaction;
}
function setMaximumCostOfSendInWei(
uint256 _maximumCostOfSendInWei
) external onlyOwner{
maximumCostOfSendInWei = _maximumCostOfSendInWei;
}
function setMinimumServerBalanceInWei(
uint256 _minimumServerBalanceInWei
) external onlyOwner{
minimumServerBalanceInWei = _minimumServerBalanceInWei;
}
function setMinimumViablePriceOfARandomNumberInWei(
uint256 _minimumViablePriceOfARandomNumberInWei
) external onlyOwner{
minimumViablePriceOfARandomNumberInWei = _minimumViablePriceOfARandomNumberInWei;
}
function setMinimumHealthyLengthOfRandomNumbersArray(
uint256 _minimumHealthyLengthOfRandomNumbersArray
) external onlyOwner{
minimumHealthyLengthOfRandomNumbersArray = _minimumHealthyLengthOfRandomNumbersArray;
}
function setPriceOfARandomNumberInWei(
uint256 _priceOfARandomNumberInWei
) internal onlyServer checkIfPaused{
require(
_priceOfARandomNumberInWei >= minimumViablePriceOfARandomNumberInWei,
"FAILURE: Server tried to set priceOfARandomNumberInWei lower than minimumViablePriceOfARandomNumberInWei."
);
priceOfARandomNumberInWei = _priceOfARandomNumberInWei;
}
function requestRandomNumbersSynchronous(
uint256 amountOfRandomNumbersToRequest,
uint256[] memory randomSeedArray
) public payable checkIfPaused checkIfDeprecated returns (uint256[] memory randomNumbersToReturn){
uint256 currentRandomNumbersArrayLength = randomNumbersArray.length;
require(
amountOfRandomNumbersToRequest > 0,
"FAILURE: You must request at least one random number."
);
require(
amountOfRandomNumbersToRequest <= currentRandomNumbersArrayLength,
"FAILURE: You requested more random numbers than we have available. Please check randomNumbersAvailable before making your request."
);
require(
msg.value >= priceOfARandomNumberInWei * amountOfRandomNumbersToRequest,
"FAILURE: You did not pay enough ETH for that amount of random numbers."
);
randomNumbersToReturn = new uint256[](amountOfRandomNumbersToRequest);
uint256 currentRandomNumber = mostRecentlyReturnedRandomNumber;
uint256 randomSeedArrayLength = randomSeedArray.length;
uint256 randomSeed;
uint256 randomNumbersArrayIndex;
for (uint256 i = 0; i < amountOfRandomNumbersToRequest; i++){
randomSeed = randomSeedArray[
currentRandomNumber % randomSeedArrayLength
];
randomNumbersArrayIndex = randomSeed % currentRandomNumbersArrayLength;
currentRandomNumber = randomNumbersArray[randomNumbersArrayIndex];
randomNumbersToReturn[i] = currentRandomNumber;
randomNumbersArray[randomNumbersArrayIndex] = randomNumbersArray[--currentRandomNumbersArrayLength];
randomNumbersArray.pop();
}
mostRecentlyReturnedRandomNumber = currentRandomNumber;
emit RandomWordsReturnedSync(msg.sender, msg.value, amountOfRandomNumbersToRequest);
return randomNumbersToReturn;
}
function requestRandomNumbersSynchronousUsingVRFv2Seed(
uint256 amountOfRandomNumbersToRequest,
Proof memory proof,
RequestCommitment memory rc
) external payable checkIfPaused checkIfDeprecated returns (uint256[] memory randomNumbersToReturn){
uint256 randomness;
(, randomness) = getRandomnessFromProof(proof, rc);
uint256[] memory randomSeedArray = new uint256[](rc.numWords);
for (uint256 i = 0; i < rc.numWords; i++) {
randomSeedArray[i] = uint256(keccak256(abi.encode(randomness, i)));
}
randomNumbersToReturn = requestRandomNumbersSynchronous(
amountOfRandomNumbersToRequest,
randomSeedArray
);
return randomNumbersToReturn;
}
// Chainlink derived code starts here:
/**
* @notice Returns the proving key hash key associated with this public key
* @param publicKey the key to return the hash of
*/
function hashOfKey(uint256[2] memory publicKey) public pure returns (bytes32) {
return keccak256(abi.encode(publicKey));
}
function getRandomnessFromProof(Proof memory proof, RequestCommitment memory rc)
private
view
returns (
uint256 requestId,
uint256 randomness
)
{
bytes32 keyHash = hashOfKey(proof.pk);
requestId = uint256(keccak256(abi.encode(keyHash, proof.seed)));
bytes32 blockHash = blockhash(rc.blockNum);
if (blockHash == bytes32(0)) {
blockHash = BLOCKHASH_STORE.getBlockhash(rc.blockNum);
if (blockHash == bytes32(0)) {
revert BlockhashNotInStore(rc.blockNum);
}
}
// The seed actually used by the VRF machinery, mixing in the blockhash
uint256 actualSeed = uint256(keccak256(abi.encodePacked(proof.seed, blockHash)));
randomness = VRF.randomValueFromVRFProof(proof, actualSeed); // Reverts on failure
}
function fulfillRandomWords(Proof memory proof, RequestCommitment memory rc) external onlyServer {
require(
rc.numWords <= maximumNumbersThatCanBeFulfilledInOneTransaction,
"FAILURE: You cannot fulfill that many random numbers."
);
uint256 randomness;
(mostRecentRequestId, randomness) = getRandomnessFromProof(proof, rc);
for (uint256 i = 0; i < rc.numWords; i++) {
randomNumbersArray.push(
uint256(keccak256(abi.encode(randomness, i)))
);
}
uint256 prospectivePriceOfARandomNumberInWei = (
(tx.gasprice * amountOfGasUsedForAFulfillRandomNumbersTransaction) / uint256(rc.numWords)
) * uint256(priceMultiplier);
if (prospectivePriceOfARandomNumberInWei >= minimumViablePriceOfARandomNumberInWei){
setPriceOfARandomNumberInWei(prospectivePriceOfARandomNumberInWei);
}
topUpServerBalance();
emit RandomWordsFulfilled(mostRecentRequestId, randomness, 0, true); // from Chainlink
}
// Chainlink derived code ends here
function withdrawETHToOwner(
uint256 weiToWithdraw
) external onlyOwner {
require(
address(this).balance > weiToWithdraw,
"FAILURE: There is not enough ETH in this contract to complete the withdrawal."
);
require(
payable(ownerAddress).send(weiToWithdraw),
"FAILURE: Failed to withdraw ETH to the owner."
);
}
function topUpServerBalance() internal onlyServer {
uint256 serverBalanceInWei = serverAddress.balance;
if(serverBalanceInWei >= minimumServerBalanceInWei){
return;
}
uint256 weiToWithdraw = minimumServerBalanceInWei - serverBalanceInWei;
if ((weiToWithdraw + maximumCostOfSendInWei) > address(this).balance){
return;
}
require(
payable(serverAddress).send(weiToWithdraw),
"FAILURE: Failed to withdraw ETH to the server."
);
}
function setReplacementContractAddress(
address _replacementContractAddress
) external onlyOwner {
replacementContractAddress = _replacementContractAddress;
}
function setPriceMultiplier(
uint8 _priceMultiplier
) external onlyOwner {
priceMultiplier = _priceMultiplier;
}
function pauseOrUnpauseContract(
bool shouldBePaused
) external onlyOwner {
contractIsPaused = shouldBePaused;
}
function randomNumbersAvailable() external view returns (uint256 amountOfRandomNumbersAvailable){
return randomNumbersArray.length;
}
}
contract Deployer {
event ContractDeployed(address deployedContractAddress);
constructor() {
emit ContractDeployed(
Create2.deploy(
0,
"RNR v1",
type(RandomNumberRetailer).creationCode
)
);
}
}