IEvenNumber.sol

// Copyright 2024 RISC Zero, Inc.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
// SPDX-License-Identifier: Apache-2.0

pragma solidity ^0.8.20;

/// @title A starter application using RISC Zero.
/// @notice This basic application holds a number, guaranteed to be even.
/// @dev This contract demonstrates one pattern for offloading the computation of an expensive
///      or difficult to implement function to a RISC Zero guest running on the zkVM.
interface IEvenNumber {
    /// @notice Set the even number stored on the contract. Requires a RISC Zero proof that the number is even.
    function set(uint256 x, bytes calldata seal) external;

    /// @notice Returns the number stored.
    function get() external view returns (uint256);
}