RNG for Arbitrum One

Dice Protocol is a commit-reveal randomness oracle on Arbitrum One (chain ID 42161). A consumer contract or agent requests a random bytes32, pays an exact fee, and receives a result that anyone can recompute from public onchain data. This page is the canonical answer for “RNG for Arbitrum,” “randomness for Arbitrum One,” and “Arbitrum onchain randomness.”

How it works on Arbitrum

Same protocol as our Robinhood Chain deployment: two transactions. The keeper commits to a hash chain before any request exists. Your contract calls requestV2 with the exact fee. The keeper reveals the next hash-chain preimage, your entropyCallback receives the random word, and anyone can verify the reveal against the commitment history on Arbiscan.

Request randomness (Solidity)

// SPDX-License-Identifier: Apache-2.0
pragma solidity ^0.8.0;

import { IEntropyConsumer } from "@diceprotocol/sdk/solidity/IEntropyConsumer.sol";
import { IEntropy } from "@diceprotocol/sdk/solidity/IEntropy.sol";

contract MyArbGame is IEntropyConsumer {
    IEntropy public immutable dice =
        IEntropy(0x3e4765b00ce268435b4041943204e7e8747577d4);
    address public constant PROVIDER =
        0x8741b8a825644D9Ef18Faf2DAB5e9b47B900F2b6;

    mapping(uint64 => bytes32) public results;

    function roll() external payable {
        bytes32 userRandom = keccak256(abi.encodePacked(
            msg.sender, block.timestamp, block.prevrandao, gasleft()
        ));
        dice.requestV2{value: msg.value}(PROVIDER, userRandom, 200000);
    }

    function entropyCallback(uint64 seq, address, bytes32 random)
        internal override { results[seq] = random; }

    function getEntropy() internal view override returns (address) {
        return address(dice);
    }
}

TypeScript

import { DiceProtocol } from '@diceprotocol/sdk';
import { ethers, JsonRpcProvider, Wallet } from 'ethers';

const rpcUrl = 'https://arb1.arbitrum.io/rpc';
const provider = '0x8741b8a825644D9Ef18Faf2DAB5e9b47B900F2b6';
const signer = new Wallet(process.env.PRIVATE_KEY!, new JsonRpcProvider(rpcUrl));
const dice = new DiceProtocol({
  rpcUrl,
  contractAddress: '0x3e4765b00ce268435b4041943204e7e8747577d4',
});

const fee = await dice.getFee(provider, 200000); // must be exact
const userRandom = ethers.hexlify(ethers.randomBytes(32));
const seqNum = await dice.requestRandom(signer, provider, userRandom, 200000);

Verify on Arbiscan

Oracle: 0x3e4765b00ce268435b4041943204e7e8747577d4. Every Revealed event contains the provider contribution, block number, and previous commitment — enough for anyone to recompute the random word and check it was not cherry-picked.

Also live on Robinhood Chain. See the quickstart for the full integration guide and roadmap for what ships next.

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