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BlockNumberBefore Enforcer

The BlockNumberBeforeEnforcer.sol smart contract adds the ability to caveat before block.numbers.


  • Mainnet: Coming Soon
  • Polygon: Coming Soon
  • Optimism: Coming Soon

How It Works

The terms field is expected to contain the block.number, after which invocations will not be valid. The block.number is passed as a bytes8.

Javascript Example

const delegation = {
delegate: '0xd8da6bf26964af9d7eed9e03e53415d37aa96045', // vitalik.eth
caveats: [
enforcer: BlockNumberBeforeEnforcer.address,
// Transaction must be executed before block.number 0x32, which is 10 in decimal format.
terms: '0x0000000000000032',

Smart Contract

contract BlockNumberBeforeEnforcer is CaveatEnforcer {
* @notice Allows the delegator to specify the latest block the delegation will be valid.
* @param terms - The block before which the delegation is valid. See test for example.
* @param transaction - The transaction the delegate might try to perform.
* @param delegationHash - The hash of the delegation being operated on.
function enforceCaveat(
bytes calldata terms,
Transaction calldata transaction,
bytes32 delegationHash
) public override returns (bool) {
uint64 blockThreshold = BytesLib.toUint64(terms, 0);
if (blockThreshold > block.number) {
return true;
} else {