Contract Address Details

// Copyright 2024 RISC Zero, Inc.
//
// The RiscZeroGroth16Verifier is a free software: you can redistribute it
// and/or modify it under the terms of the GNU General Public License as
// published by the Free Software Foundation, either version 3 of the License,
// or (at your option) any later version.
//
// The RiscZeroGroth16Verifier is distributed in the hope that it will be
// useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General
// Public License for more details.
//
// You should have received a copy of the GNU General Public License along with
// the RiscZeroGroth16Verifier. If not, see <https://www.gnu.org/licenses/>.
//
// SPDX-License-Identifier: GPL-3.0

pragma solidity ^0.8.9;

import {SafeCast} from "openzeppelin/contracts/utils/math/SafeCast.sol";

import {ControlID} from "./ControlID.sol";
import {Groth16Verifier} from "./Groth16Verifier.sol";
import {
    ExitCode,
    IRiscZeroVerifier,
    Output,
    OutputLib,
    Receipt,
    ReceiptClaim,
    ReceiptClaimLib,
    SystemExitCode,
    VerificationFailed
} from "../IRiscZeroVerifier.sol";
import {StructHash} from "../StructHash.sol";
import {reverseByteOrderUint256, reverseByteOrderUint32} from "../Util.sol";
import {IRiscZeroSelectable} from "../IRiscZeroSelectable.sol";

/// @notice A Groth16 seal over the claimed receipt claim.
struct Seal {
    uint256[2] a;
    uint256[2][2] b;
    uint256[2] c;
}

/// @notice Error raised when this verifier receives a receipt with a selector that does not match
///         its own. The selector value is calculated from the verifier parameters, and so this
///         usually indicates a mismatch between the version of the prover and this verifier.
error SelectorMismatch(bytes4 received, bytes4 expected);

/// @notice Groth16 verifier contract for RISC Zero receipts of execution.
contract RiscZeroGroth16Verifier is IRiscZeroVerifier, IRiscZeroSelectable, Groth16Verifier {
    using ReceiptClaimLib for ReceiptClaim;
    using OutputLib for Output;
    using SafeCast for uint256;

    /// @notice Semantic version of the RISC Zero system of which this contract is part.
    /// @dev This is set to be equal to the version of the risc0-zkvm crate.
    string public constant VERSION = "3.0.0";

    /// @notice Control root hash binding the set of circuits in the RISC Zero system.
    /// @dev This value controls what set of recursion programs (e.g. lift, join, resolve), and
    /// therefore what version of the zkVM circuit, will be accepted by this contract. Each
    /// instance of this verifier contract will accept a single release of the RISC Zero circuits.
    ///
    /// New releases of RISC Zero's zkVM require updating these values. These values can be
    /// calculated from the [risc0 monorepo][1] using: `cargo xtask bootstrap`.
    ///
    /// [1]: https://github.com/risc0/risc0
    bytes16 public immutable CONTROL_ROOT_0;
    bytes16 public immutable CONTROL_ROOT_1;
    bytes32 public immutable BN254_CONTROL_ID;

    /// @notice A short key attached to the seal to select the correct verifier implementation.
    /// @dev The selector is taken from the hash of the verifier parameters including the Groth16
    ///      verification key and the control IDs that commit to the RISC Zero circuits. If two
    ///      receipts have different selectors (i.e. different verifier parameters), then it can
    ///      generally be assumed that they need distinct verifier implementations. This is used as
    ///      part of the RISC Zero versioning mechanism.
    ///
    ///      A selector is not intended to be collision resistant, in that it is possible to find
    ///      two preimages that result in the same selector. This is acceptable since it's purpose
    ///      to a route a request among a set of trusted verifiers, and to make errors of sending a
    ///      receipt to a mismatching verifiers easier to debug. It is analogous to the ABI
    ///      function selectors.
    bytes4 public immutable SELECTOR;

    /// @notice Identifier for the Groth16 verification key encoded into the base contract.
    /// @dev This value is computed at compile time.
    function verifier_key_digest() internal pure returns (bytes32) {
        bytes32[] memory ic_digests = new bytes32[](6);
        ic_digests[0] = sha256(abi.encodePacked(IC0x, IC0y));
        ic_digests[1] = sha256(abi.encodePacked(IC1x, IC1y));
        ic_digests[2] = sha256(abi.encodePacked(IC2x, IC2y));
        ic_digests[3] = sha256(abi.encodePacked(IC3x, IC3y));
        ic_digests[4] = sha256(abi.encodePacked(IC4x, IC4y));
        ic_digests[5] = sha256(abi.encodePacked(IC5x, IC5y));

        return sha256(
            abi.encodePacked(
                // tag
                sha256("risc0_groth16.VerifyingKey"),
                // down
                sha256(abi.encodePacked(alphax, alphay)),
                sha256(abi.encodePacked(betax1, betax2, betay1, betay2)),
                sha256(abi.encodePacked(gammax1, gammax2, gammay1, gammay2)),
                sha256(abi.encodePacked(deltax1, deltax2, deltay1, deltay2)),
                StructHash.taggedList(sha256("risc0_groth16.VerifyingKey.IC"), ic_digests),
                // down length
                uint16(5) << 8
            )
        );
    }

    constructor(bytes32 control_root, bytes32 bn254_control_id) {
        (CONTROL_ROOT_0, CONTROL_ROOT_1) = splitDigest(control_root);
        BN254_CONTROL_ID = bn254_control_id;

        SELECTOR = bytes4(
            sha256(
                abi.encodePacked(
                    // tag
                    sha256("risc0.Groth16ReceiptVerifierParameters"),
                    // down
                    control_root,
                    reverseByteOrderUint256(uint256(bn254_control_id)),
                    verifier_key_digest(),
                    // down length
                    uint16(3) << 8
                )
            )
        );
    }

    /// @notice splits a digest into two 128-bit halves to use as public signal inputs.
    /// @dev RISC Zero's Circom verifier circuit takes each of two hash digests in two 128-bit
    /// chunks. These values can be derived from the digest by splitting the digest in half and
    /// then reversing the bytes of each.
    function splitDigest(bytes32 digest) internal pure returns (bytes16, bytes16) {
        uint256 reversed = reverseByteOrderUint256(uint256(digest));
        return (bytes16(uint128(reversed)), bytes16(uint128(reversed >> 128)));
    }

    /// @inheritdoc IRiscZeroVerifier
    function verify(bytes calldata seal, bytes32 imageId, bytes32 journalDigest) external view {
        _verifyIntegrity(seal, ReceiptClaimLib.ok(imageId, journalDigest).digest());
    }

    /// @inheritdoc IRiscZeroVerifier
    function verifyIntegrity(Receipt calldata receipt) external view {
        return _verifyIntegrity(receipt.seal, receipt.claimDigest);
    }

    /// @notice internal implementation of verifyIntegrity, factored to avoid copying calldata bytes to memory.
    function _verifyIntegrity(bytes calldata seal, bytes32 claimDigest) internal view {
        // Check that the seal has a matching selector. Mismatch generally indicates that the
        // prover and this verifier are using different parameters, and so the verification
        // will not succeed.
        if (SELECTOR != bytes4(seal[:4])) {
            revert SelectorMismatch({received: bytes4(seal[:4]), expected: SELECTOR});
        }

        // Run the Groth16 verify procedure.
        (bytes16 claim0, bytes16 claim1) = splitDigest(claimDigest);
        Seal memory decodedSeal = abi.decode(seal[4:], (Seal));
        bool verified = this.verifyProof(
            decodedSeal.a,
            decodedSeal.b,
            decodedSeal.c,
            [
                uint256(uint128(CONTROL_ROOT_0)),
                uint256(uint128(CONTROL_ROOT_1)),
                uint256(uint128(claim0)),
                uint256(uint128(claim1)),
                uint256(BN254_CONTROL_ID)
            ]
        );

        // Revert is verification failed.
        if (!verified) {
            revert VerificationFailed();
        }
    }
}
        

// Copyright 2025 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 ^0.8.9;

/// @notice Selectable interface for RISC Zero verifier.
interface IRiscZeroSelectable {
    /// @notice A short key attached to the seal to select the correct verifier implementation.
    /// @dev The selector is taken from the hash of the verifier parameters. If two
    ///      receipts have different selectors (i.e. different verifier parameters), then it can
    ///      generally be assumed that they need distinct verifier implementations. This is used as
    ///      part of the RISC Zero versioning mechanism.
    ///
    ///      A selector is not intended to be collision resistant, in that it is possible to find
    ///      two preimages that result in the same selector. This is acceptable since it's purpose
    ///      to a route a request among a set of trusted verifiers, and to make errors of sending a
    ///      receipt to a mismatching verifiers easier to debug. It is analogous to the ABI
    ///      function selectors.
    function SELECTOR() external view returns (bytes4);
}
          

// Copyright 2025 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 ^0.8.9;

import {reverseByteOrderUint32} from "./Util.sol";

/// @notice A receipt attesting to a claim using the RISC Zero proof system.
/// @dev A receipt contains two parts: a seal and a claim.
///
/// The seal is a zero-knowledge proof attesting to knowledge of a witness for the claim. The claim
/// is a set of public outputs, and for zkVM execution is the hash of a `ReceiptClaim` struct.
///
/// IMPORTANT: The `claimDigest` field must be a hash computed by the caller for verification to
/// have meaningful guarantees. Treat this similar to verifying an ECDSA signature, in that hashing
/// is a key operation in verification. The most common way to calculate this hash is to use the
/// `ReceiptClaimLib.ok(imageId, journalDigest).digest()` for successful executions.
struct Receipt {
    bytes seal;
    bytes32 claimDigest;
}

/// @notice Public claims about a zkVM guest execution, such as the journal committed to by the guest.
/// @dev Also includes important information such as the exit code and the starting and ending system
/// state (i.e. the state of memory). `ReceiptClaim` is a "Merkle-ized struct" supporting
/// partial openings of the underlying fields from a hash commitment to the full structure.
struct ReceiptClaim {
    /// @notice Digest of the SystemState just before execution has begun.
    bytes32 preStateDigest;
    /// @notice Digest of the SystemState just after execution has completed.
    bytes32 postStateDigest;
    /// @notice The exit code for the execution.
    ExitCode exitCode;
    /// @notice A digest of the input to the guest.
    /// @dev This field is currently unused and must be set to the zero digest.
    bytes32 input;
    /// @notice Digest of the Output of the guest, including the journal
    /// and assumptions set during execution.
    bytes32 output;
}

library ReceiptClaimLib {
    using OutputLib for Output;
    using SystemStateLib for SystemState;

    bytes32 constant TAG_DIGEST = sha256("risc0.ReceiptClaim");

    // Define a constant to ensure hashing is done at compile time. Can't use the
    // SystemStateLib.digest method here because the Solidity compiler complains.
    bytes32 constant SYSTEM_STATE_ZERO_DIGEST = 0xa3acc27117418996340b84e5a90f3ef4c49d22c79e44aad822ec9c313e1eb8e2;

    /// @notice Construct a ReceiptClaim from the given imageId and journalDigest.
    ///         Returned ReceiptClaim will represent a successful execution of the zkVM, running
    ///         the program committed by imageId and resulting in the journal specified by
    ///         journalDigest.
    /// @param imageId The identifier for the guest program.
    /// @param journalDigest The SHA-256 digest of the journal bytes.
    /// @dev Input hash and postStateDigest are set to all-zeros (i.e. no committed input, or
    ///      final memory state), the exit code is (Halted, 0), and there are no assumptions
    ///      (i.e. the receipt is unconditional).
    function ok(bytes32 imageId, bytes32 journalDigest) internal pure returns (ReceiptClaim memory) {
        return ReceiptClaim(
            imageId,
            SYSTEM_STATE_ZERO_DIGEST,
            ExitCode(SystemExitCode.Halted, 0),
            bytes32(0),
            Output(journalDigest, bytes32(0)).digest()
        );
    }

    function digest(ReceiptClaim memory claim) internal pure returns (bytes32) {
        return sha256(
            abi.encodePacked(
                TAG_DIGEST,
                // down
                claim.input,
                claim.preStateDigest,
                claim.postStateDigest,
                claim.output,
                // data
                uint32(claim.exitCode.system) << 24,
                uint32(claim.exitCode.user) << 24,
                // down.length
                uint16(4) << 8
            )
        );
    }
}

/// @notice Commitment to the memory state and program counter (pc) of the zkVM.
/// @dev The "pre" and "post" fields of the ReceiptClaim are digests of the system state at the
///      start are stop of execution. Programs are loaded into the zkVM by creating a memory image
///      of the loaded program, and creating a system state for initializing the zkVM. This is
///      known as the "image ID".
struct SystemState {
    /// @notice Program counter.
    uint32 pc;
    /// @notice Root hash of a merkle tree which confirms the integrity of the memory image.
    bytes32 merkle_root;
}

library SystemStateLib {
    bytes32 constant TAG_DIGEST = sha256("risc0.SystemState");

    function digest(SystemState memory state) internal pure returns (bytes32) {
        return sha256(
            abi.encodePacked(
                TAG_DIGEST,
                // down
                state.merkle_root,
                // data
                reverseByteOrderUint32(state.pc),
                // down.length
                uint16(1) << 8
            )
        );
    }
}

/// @notice Exit condition indicated by the zkVM at the end of the guest execution.
/// @dev Exit codes have a "system" part and a "user" part. Semantically, the system part is set to
/// indicate the type of exit (e.g. halt, pause, or system split) and is directly controlled by the
/// zkVM. The user part is an exit code, similar to exit codes used in Linux, chosen by the guest
/// program to indicate additional information (e.g. 0 to indicate success or 1 to indicate an
/// error).
struct ExitCode {
    SystemExitCode system;
    uint8 user;
}

/// @notice Exit condition indicated by the zkVM at the end of the execution covered by this proof.
/// @dev
/// `Halted` indicates normal termination of a program with an interior exit code returned from the
/// guest program. A halted program cannot be resumed.
///
/// `Paused` indicates the execution ended in a paused state with an interior exit code set by the
/// guest program. A paused program can be resumed such that execution picks up where it left
/// of, with the same memory state.
///
/// `SystemSplit` indicates the execution ended on a host-initiated system split. System split is
/// mechanism by which the host can temporarily stop execution of the execution ended in a system
/// split has no output and no conclusions can be drawn about whether the program will eventually
/// halt. System split is used in continuations to split execution into individually provable segments.
enum SystemExitCode {
    Halted,
    Paused,
    SystemSplit
}

/// @notice Output field in the `ReceiptClaim`, committing to a claimed journal and assumptions list.
struct Output {
    /// @notice Digest of the journal committed to by the guest execution.
    bytes32 journalDigest;
    /// @notice Digest of the ordered list of `ReceiptClaim` digests corresponding to the
    /// calls to `env::verify` and `env::verify_integrity`.
    /// @dev Verifying the integrity of a `Receipt` corresponding to a `ReceiptClaim` with a
    /// non-empty assumptions list does not guarantee unconditionally any of the claims over the
    /// guest execution (i.e. if the assumptions list is non-empty, then the journal digest cannot
    /// be trusted to correspond to a genuine execution). The claims can be checked by additional
    /// verifying a `Receipt` for every digest in the assumptions list.
    bytes32 assumptionsDigest;
}

library OutputLib {
    bytes32 constant TAG_DIGEST = sha256("risc0.Output");

    function digest(Output memory output) internal pure returns (bytes32) {
        return sha256(
            abi.encodePacked(
                TAG_DIGEST,
                // down
                output.journalDigest,
                output.assumptionsDigest,
                // down.length
                uint16(2) << 8
            )
        );
    }
}

/// @notice Error raised when cryptographic verification of the zero-knowledge proof fails.
error VerificationFailed();

/// @notice Verifier interface for RISC Zero receipts of execution.
interface IRiscZeroVerifier {
    /// @notice Verify that the given seal is a valid RISC Zero proof of execution with the
    ///     given image ID and journal digest. Reverts on failure.
    /// @dev This method additionally ensures that the input hash is all-zeros (i.e. no
    /// committed input), the exit code is (Halted, 0), and there are no assumptions (i.e. the
    /// receipt is unconditional).
    /// @param seal The encoded cryptographic proof (i.e. SNARK).
    /// @param imageId The identifier for the guest program.
    /// @param journalDigest The SHA-256 digest of the journal bytes.
    function verify(bytes calldata seal, bytes32 imageId, bytes32 journalDigest) external view;

    /// @notice Verify that the given receipt is a valid RISC Zero receipt, ensuring the `seal` is
    /// valid a cryptographic proof of the execution with the given `claim`. Reverts on failure.
    /// @param receipt The receipt to be verified.
    function verifyIntegrity(Receipt calldata receipt) external view;
}
          

// 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 ^0.8.9;

import {SafeCast} from "openzeppelin/contracts/utils/math/SafeCast.sol";

import {reverseByteOrderUint16} from "./Util.sol";

/// @notice Structural hashing routines used for RISC Zero data structures.
/// @dev
/// StructHash implements hashing for structs, incorporating type tags for domain separation.
/// The goals of this library are:
/// * Collision resistance: it should not be possible to find two semantically distinct values that
///   produce the same digest.
/// * Simplicity: implementations should be simple to understand and write, as these methods must
///   be implemented in multiple languages and environments, including zkSNARK circuits.
/// * Incremental openings: it should be possible to incrementally open a nested struct without
///   needing to open (very many) extra fields (i.e. the struct should be "Merkle-ized").
library StructHash {
    using SafeCast for uint256;

    // @notice Compute the struct digest with the given tag digest and digest fields down.
    function taggedStruct(bytes32 tagDigest, bytes32[] memory down) internal pure returns (bytes32) {
        bytes memory data = new bytes(0);
        return taggedStruct(tagDigest, down, data);
    }

    // @notice Compute the struct digest with the given tag digest, digest fields down, and data.
    function taggedStruct(bytes32 tagDigest, bytes32[] memory down, bytes memory data)
        internal
        pure
        returns (bytes32)
    {
        uint16 downLen = down.length.toUint16();
        // swap the byte order to encode as little-endian.
        bytes2 downLenLE = bytes2((downLen << 8) | (downLen >> 8));
        return sha256(abi.encodePacked(tagDigest, down, data, downLenLE));
    }

    // @notice Add an element (head) to the incremental hash of a list (tail).
    function taggedListCons(bytes32 tagDigest, bytes32 head, bytes32 tail) internal pure returns (bytes32) {
        bytes32[] memory down = new bytes32[](2);
        down[0] = head;
        down[1] = tail;
        return taggedStruct(tagDigest, down);
    }

    // @notice Hash the list by using taggedListCons to repeatedly add to the head of the list.
    function taggedList(bytes32 tagDigest, bytes32[] memory list) internal pure returns (bytes32) {
        bytes32 curr = bytes32(0x0000000000000000000000000000000000000000000000000000000000000000);
        for (uint256 i = 0; i < list.length; i++) {
            curr = taggedListCons(tagDigest, list[list.length - 1 - i], curr);
        }
        return curr;
    }
}
          

// 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 ^0.8.9;

/// @notice reverse the byte order of the uint256 value.
/// @dev Solidity uses a big-endian ABI encoding. Reversing the byte order before encoding
/// ensure that the encoded value will be little-endian.
/// Written by k06a. https://ethereum.stackexchange.com/a/83627
function reverseByteOrderUint256(uint256 input) pure returns (uint256 v) {
    v = input;

    // swap bytes
    v = ((v & 0xFF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00) >> 8)
        | ((v & 0x00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF00FF) << 8);

    // swap 2-byte long pairs
    v = ((v & 0xFFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000) >> 16)
        | ((v & 0x0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF0000FFFF) << 16);

    // swap 4-byte long pairs
    v = ((v & 0xFFFFFFFF00000000FFFFFFFF00000000FFFFFFFF00000000FFFFFFFF00000000) >> 32)
        | ((v & 0x00000000FFFFFFFF00000000FFFFFFFF00000000FFFFFFFF00000000FFFFFFFF) << 32);

    // swap 8-byte long pairs
    v = ((v & 0xFFFFFFFFFFFFFFFF0000000000000000FFFFFFFFFFFFFFFF0000000000000000) >> 64)
        | ((v & 0x0000000000000000FFFFFFFFFFFFFFFF0000000000000000FFFFFFFFFFFFFFFF) << 64);

    // swap 16-byte long pairs
    v = (v >> 128) | (v << 128);
}

/// @notice reverse the byte order of the uint32 value.
/// @dev Solidity uses a big-endian ABI encoding. Reversing the byte order before encoding
/// ensure that the encoded value will be little-endian.
/// Written by k06a. https://ethereum.stackexchange.com/a/83627
function reverseByteOrderUint32(uint32 input) pure returns (uint32 v) {
    v = input;

    // swap bytes
    v = ((v & 0xFF00FF00) >> 8) | ((v & 0x00FF00FF) << 8);

    // swap 2-byte long pairs
    v = (v >> 16) | (v << 16);
}

/// @notice reverse the byte order of the uint16 value.
/// @dev Solidity uses a big-endian ABI encoding. Reversing the byte order before encoding
/// ensure that the encoded value will be little-endian.
/// Written by k06a. https://ethereum.stackexchange.com/a/83627
function reverseByteOrderUint16(uint16 input) pure returns (uint16 v) {
    v = input;

    // swap bytes
    v = (v >> 8) | ((v & 0x00FF) << 8);
}
          

// Copyright 2025 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

// This file is automatically generated by:
// cargo xtask bootstrap-groth16

pragma solidity ^0.8.9;

library ControlID {
    bytes32 public constant CONTROL_ROOT = hex"a54dc85ac99f851c92d7c96d7318af41dbe7c0194edfcc37eb4d422a998c1f56";
    // NOTE: This has the opposite byte order to the value in the risc0 repository.
    bytes32 public constant BN254_CONTROL_ID = hex"04446e66d300eb7fb45c9726bb53c793dda407a62e9601618bb43c5c14657ac0";
}
          

// SPDX-License-Identifier: GPL-3.0
/*
    Copyright 2021 0KIMS association.

    This file is generated with [snarkJS](https://github.com/iden3/snarkjs).

    snarkJS is a free software: you can redistribute it and/or modify it
    under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    snarkJS is distributed in the hope that it will be useful, but WITHOUT
    ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
    License for more details.

    You should have received a copy of the GNU General Public License
    along with snarkJS. If not, see <https://www.gnu.org/licenses/>.
*/

pragma solidity >=0.7.0 <0.9.0;

contract Groth16Verifier {
    // Scalar field size
    uint256 constant r = 21888242871839275222246405745257275088548364400416034343698204186575808495617;
    // Base field size
    uint256 constant q = 21888242871839275222246405745257275088696311157297823662689037894645226208583;

    // Verification Key data
    uint256 constant alphax = 20491192805390485299153009773594534940189261866228447918068658471970481763042;
    uint256 constant alphay = 9383485363053290200918347156157836566562967994039712273449902621266178545958;
    uint256 constant betax1 = 4252822878758300859123897981450591353533073413197771768651442665752259397132;
    uint256 constant betax2 = 6375614351688725206403948262868962793625744043794305715222011528459656738731;
    uint256 constant betay1 = 21847035105528745403288232691147584728191162732299865338377159692350059136679;
    uint256 constant betay2 = 10505242626370262277552901082094356697409835680220590971873171140371331206856;
    uint256 constant gammax1 = 11559732032986387107991004021392285783925812861821192530917403151452391805634;
    uint256 constant gammax2 = 10857046999023057135944570762232829481370756359578518086990519993285655852781;
    uint256 constant gammay1 = 4082367875863433681332203403145435568316851327593401208105741076214120093531;
    uint256 constant gammay2 = 8495653923123431417604973247489272438418190587263600148770280649306958101930;
    uint256 constant deltax1 = 1668323501672964604911431804142266013250380587483576094566949227275849579036;
    uint256 constant deltax2 = 12043754404802191763554326994664886008979042643626290185762540825416902247219;
    uint256 constant deltay1 = 7710631539206257456743780535472368339139328733484942210876916214502466455394;
    uint256 constant deltay2 = 13740680757317479711909903993315946540841369848973133181051452051592786724563;

    uint256 constant IC0x = 8446592859352799428420270221449902464741693648963397251242447530457567083492;
    uint256 constant IC0y = 1064796367193003797175961162477173481551615790032213185848276823815288302804;

    uint256 constant IC1x = 3179835575189816632597428042194253779818690147323192973511715175294048485951;
    uint256 constant IC1y = 20895841676865356752879376687052266198216014795822152491318012491767775979074;

    uint256 constant IC2x = 5332723250224941161709478398807683311971555792614491788690328996478511465287;
    uint256 constant IC2y = 21199491073419440416471372042641226693637837098357067793586556692319371762571;

    uint256 constant IC3x = 12457994489566736295787256452575216703923664299075106359829199968023158780583;
    uint256 constant IC3y = 19706766271952591897761291684837117091856807401404423804318744964752784280790;

    uint256 constant IC4x = 19617808913178163826953378459323299110911217259216006187355745713323154132237;
    uint256 constant IC4y = 21663537384585072695701846972542344484111393047775983928357046779215877070466;

    uint256 constant IC5x = 6834578911681792552110317589222010969491336870276623105249474534788043166867;
    uint256 constant IC5y = 15060583660288623605191393599883223885678013570733629274538391874953353488393;

    // Memory data
    uint16 constant pVk = 0;
    uint16 constant pPairing = 128;

    uint16 constant pLastMem = 896;

    function verifyProof(
        uint256[2] calldata _pA,
        uint256[2][2] calldata _pB,
        uint256[2] calldata _pC,
        uint256[5] calldata _pubSignals
    ) public view returns (bool) {
        assembly {
            function checkField(v) {
                if iszero(lt(v, r)) {
                    mstore(0, 0)
                    return(0, 0x20)
                }
            }

            // G1 function to multiply a G1 value(x,y) to value in an address
            function g1_mulAccC(pR, x, y, s) {
                let success
                let mIn := mload(0x40)
                mstore(mIn, x)
                mstore(add(mIn, 32), y)
                mstore(add(mIn, 64), s)

                success := staticcall(sub(gas(), 2000), 7, mIn, 96, mIn, 64)

                if iszero(success) {
                    mstore(0, 0)
                    return(0, 0x20)
                }

                mstore(add(mIn, 64), mload(pR))
                mstore(add(mIn, 96), mload(add(pR, 32)))

                success := staticcall(sub(gas(), 2000), 6, mIn, 128, pR, 64)

                if iszero(success) {
                    mstore(0, 0)
                    return(0, 0x20)
                }
            }

            function checkPairing(pA, pB, pC, pubSignals, pMem) -> isOk {
                let _pPairing := add(pMem, pPairing)
                let _pVk := add(pMem, pVk)

                mstore(_pVk, IC0x)
                mstore(add(_pVk, 32), IC0y)

                // Compute the linear combination vk_x

                g1_mulAccC(_pVk, IC1x, IC1y, calldataload(add(pubSignals, 0)))

                g1_mulAccC(_pVk, IC2x, IC2y, calldataload(add(pubSignals, 32)))

                g1_mulAccC(_pVk, IC3x, IC3y, calldataload(add(pubSignals, 64)))

                g1_mulAccC(_pVk, IC4x, IC4y, calldataload(add(pubSignals, 96)))

                g1_mulAccC(_pVk, IC5x, IC5y, calldataload(add(pubSignals, 128)))

                // -A
                mstore(_pPairing, calldataload(pA))
                mstore(add(_pPairing, 32), mod(sub(q, calldataload(add(pA, 32))), q))

                // B
                mstore(add(_pPairing, 64), calldataload(pB))
                mstore(add(_pPairing, 96), calldataload(add(pB, 32)))
                mstore(add(_pPairing, 128), calldataload(add(pB, 64)))
                mstore(add(_pPairing, 160), calldataload(add(pB, 96)))

                // alpha1
                mstore(add(_pPairing, 192), alphax)
                mstore(add(_pPairing, 224), alphay)

                // beta2
                mstore(add(_pPairing, 256), betax1)
                mstore(add(_pPairing, 288), betax2)
                mstore(add(_pPairing, 320), betay1)
                mstore(add(_pPairing, 352), betay2)

                // vk_x
                mstore(add(_pPairing, 384), mload(add(pMem, pVk)))
                mstore(add(_pPairing, 416), mload(add(pMem, add(pVk, 32))))

                // gamma2
                mstore(add(_pPairing, 448), gammax1)
                mstore(add(_pPairing, 480), gammax2)
                mstore(add(_pPairing, 512), gammay1)
                mstore(add(_pPairing, 544), gammay2)

                // C
                mstore(add(_pPairing, 576), calldataload(pC))
                mstore(add(_pPairing, 608), calldataload(add(pC, 32)))

                // delta2
                mstore(add(_pPairing, 640), deltax1)
                mstore(add(_pPairing, 672), deltax2)
                mstore(add(_pPairing, 704), deltay1)
                mstore(add(_pPairing, 736), deltay2)

                let success := staticcall(sub(gas(), 2000), 8, _pPairing, 768, _pPairing, 0x20)

                isOk := and(success, mload(_pPairing))
            }

            let pMem := mload(0x40)
            mstore(0x40, add(pMem, pLastMem))

            // Validate that all evaluations ∈ F

            checkField(calldataload(add(_pubSignals, 0)))

            checkField(calldataload(add(_pubSignals, 32)))

            checkField(calldataload(add(_pubSignals, 64)))

            checkField(calldataload(add(_pubSignals, 96)))

            checkField(calldataload(add(_pubSignals, 128)))

            // Validate all evaluations
            let isValid := checkPairing(_pA, _pB, _pC, _pubSignals, pMem)

            mstore(0, isValid)
            return(0, 0x20)
        }
    }
}
          

// SPDX-License-Identifier: MIT
// OpenZeppelin Contracts (last updated v4.8.0) (utils/math/SafeCast.sol)
// This file was procedurally generated from scripts/generate/templates/SafeCast.js.

pragma solidity ^0.8.0;

/**
 * @dev Wrappers over Solidity's uintXX/intXX casting operators with added overflow
 * checks.
 *
 * Downcasting from uint256/int256 in Solidity does not revert on overflow. This can
 * easily result in undesired exploitation or bugs, since developers usually
 * assume that overflows raise errors. `SafeCast` restores this intuition by
 * reverting the transaction when such an operation overflows.
 *
 * Using this library instead of the unchecked operations eliminates an entire
 * class of bugs, so it's recommended to use it always.
 *
 * Can be combined with {SafeMath} and {SignedSafeMath} to extend it to smaller types, by performing
 * all math on `uint256` and `int256` and then downcasting.
 */
library SafeCast {
    /**
     * @dev Returns the downcasted uint248 from uint256, reverting on
     * overflow (when the input is greater than largest uint248).
     *
     * Counterpart to Solidity's `uint248` operator.
     *
     * Requirements:
     *
     * - input must fit into 248 bits
     *
     * _Available since v4.7._
     */
    function toUint248(uint256 value) internal pure returns (uint248) {
        require(value <= type(uint248).max, "SafeCast: value doesn't fit in 248 bits");
        return uint248(value);
    }

    /**
     * @dev Returns the downcasted uint240 from uint256, reverting on
     * overflow (when the input is greater than largest uint240).
     *
     * Counterpart to Solidity's `uint240` operator.
     *
     * Requirements:
     *
     * - input must fit into 240 bits
     *
     * _Available since v4.7._
     */
    function toUint240(uint256 value) internal pure returns (uint240) {
        require(value <= type(uint240).max, "SafeCast: value doesn't fit in 240 bits");
        return uint240(value);
    }

    /**
     * @dev Returns the downcasted uint232 from uint256, reverting on
     * overflow (when the input is greater than largest uint232).
     *
     * Counterpart to Solidity's `uint232` operator.
     *
     * Requirements:
     *
     * - input must fit into 232 bits
     *
     * _Available since v4.7._
     */
    function toUint232(uint256 value) internal pure returns (uint232) {
        require(value <= type(uint232).max, "SafeCast: value doesn't fit in 232 bits");
        return uint232(value);
    }

    /**
     * @dev Returns the downcasted uint224 from uint256, reverting on
     * overflow (when the input is greater than largest uint224).
     *
     * Counterpart to Solidity's `uint224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     *
     * _Available since v4.2._
     */
    function toUint224(uint256 value) internal pure returns (uint224) {
        require(value <= type(uint224).max, "SafeCast: value doesn't fit in 224 bits");
        return uint224(value);
    }

    /**
     * @dev Returns the downcasted uint216 from uint256, reverting on
     * overflow (when the input is greater than largest uint216).
     *
     * Counterpart to Solidity's `uint216` operator.
     *
     * Requirements:
     *
     * - input must fit into 216 bits
     *
     * _Available since v4.7._
     */
    function toUint216(uint256 value) internal pure returns (uint216) {
        require(value <= type(uint216).max, "SafeCast: value doesn't fit in 216 bits");
        return uint216(value);
    }

    /**
     * @dev Returns the downcasted uint208 from uint256, reverting on
     * overflow (when the input is greater than largest uint208).
     *
     * Counterpart to Solidity's `uint208` operator.
     *
     * Requirements:
     *
     * - input must fit into 208 bits
     *
     * _Available since v4.7._
     */
    function toUint208(uint256 value) internal pure returns (uint208) {
        require(value <= type(uint208).max, "SafeCast: value doesn't fit in 208 bits");
        return uint208(value);
    }

    /**
     * @dev Returns the downcasted uint200 from uint256, reverting on
     * overflow (when the input is greater than largest uint200).
     *
     * Counterpart to Solidity's `uint200` operator.
     *
     * Requirements:
     *
     * - input must fit into 200 bits
     *
     * _Available since v4.7._
     */
    function toUint200(uint256 value) internal pure returns (uint200) {
        require(value <= type(uint200).max, "SafeCast: value doesn't fit in 200 bits");
        return uint200(value);
    }

    /**
     * @dev Returns the downcasted uint192 from uint256, reverting on
     * overflow (when the input is greater than largest uint192).
     *
     * Counterpart to Solidity's `uint192` operator.
     *
     * Requirements:
     *
     * - input must fit into 192 bits
     *
     * _Available since v4.7._
     */
    function toUint192(uint256 value) internal pure returns (uint192) {
        require(value <= type(uint192).max, "SafeCast: value doesn't fit in 192 bits");
        return uint192(value);
    }

    /**
     * @dev Returns the downcasted uint184 from uint256, reverting on
     * overflow (when the input is greater than largest uint184).
     *
     * Counterpart to Solidity's `uint184` operator.
     *
     * Requirements:
     *
     * - input must fit into 184 bits
     *
     * _Available since v4.7._
     */
    function toUint184(uint256 value) internal pure returns (uint184) {
        require(value <= type(uint184).max, "SafeCast: value doesn't fit in 184 bits");
        return uint184(value);
    }

    /**
     * @dev Returns the downcasted uint176 from uint256, reverting on
     * overflow (when the input is greater than largest uint176).
     *
     * Counterpart to Solidity's `uint176` operator.
     *
     * Requirements:
     *
     * - input must fit into 176 bits
     *
     * _Available since v4.7._
     */
    function toUint176(uint256 value) internal pure returns (uint176) {
        require(value <= type(uint176).max, "SafeCast: value doesn't fit in 176 bits");
        return uint176(value);
    }

    /**
     * @dev Returns the downcasted uint168 from uint256, reverting on
     * overflow (when the input is greater than largest uint168).
     *
     * Counterpart to Solidity's `uint168` operator.
     *
     * Requirements:
     *
     * - input must fit into 168 bits
     *
     * _Available since v4.7._
     */
    function toUint168(uint256 value) internal pure returns (uint168) {
        require(value <= type(uint168).max, "SafeCast: value doesn't fit in 168 bits");
        return uint168(value);
    }

    /**
     * @dev Returns the downcasted uint160 from uint256, reverting on
     * overflow (when the input is greater than largest uint160).
     *
     * Counterpart to Solidity's `uint160` operator.
     *
     * Requirements:
     *
     * - input must fit into 160 bits
     *
     * _Available since v4.7._
     */
    function toUint160(uint256 value) internal pure returns (uint160) {
        require(value <= type(uint160).max, "SafeCast: value doesn't fit in 160 bits");
        return uint160(value);
    }

    /**
     * @dev Returns the downcasted uint152 from uint256, reverting on
     * overflow (when the input is greater than largest uint152).
     *
     * Counterpart to Solidity's `uint152` operator.
     *
     * Requirements:
     *
     * - input must fit into 152 bits
     *
     * _Available since v4.7._
     */
    function toUint152(uint256 value) internal pure returns (uint152) {
        require(value <= type(uint152).max, "SafeCast: value doesn't fit in 152 bits");
        return uint152(value);
    }

    /**
     * @dev Returns the downcasted uint144 from uint256, reverting on
     * overflow (when the input is greater than largest uint144).
     *
     * Counterpart to Solidity's `uint144` operator.
     *
     * Requirements:
     *
     * - input must fit into 144 bits
     *
     * _Available since v4.7._
     */
    function toUint144(uint256 value) internal pure returns (uint144) {
        require(value <= type(uint144).max, "SafeCast: value doesn't fit in 144 bits");
        return uint144(value);
    }

    /**
     * @dev Returns the downcasted uint136 from uint256, reverting on
     * overflow (when the input is greater than largest uint136).
     *
     * Counterpart to Solidity's `uint136` operator.
     *
     * Requirements:
     *
     * - input must fit into 136 bits
     *
     * _Available since v4.7._
     */
    function toUint136(uint256 value) internal pure returns (uint136) {
        require(value <= type(uint136).max, "SafeCast: value doesn't fit in 136 bits");
        return uint136(value);
    }

    /**
     * @dev Returns the downcasted uint128 from uint256, reverting on
     * overflow (when the input is greater than largest uint128).
     *
     * Counterpart to Solidity's `uint128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v2.5._
     */
    function toUint128(uint256 value) internal pure returns (uint128) {
        require(value <= type(uint128).max, "SafeCast: value doesn't fit in 128 bits");
        return uint128(value);
    }

    /**
     * @dev Returns the downcasted uint120 from uint256, reverting on
     * overflow (when the input is greater than largest uint120).
     *
     * Counterpart to Solidity's `uint120` operator.
     *
     * Requirements:
     *
     * - input must fit into 120 bits
     *
     * _Available since v4.7._
     */
    function toUint120(uint256 value) internal pure returns (uint120) {
        require(value <= type(uint120).max, "SafeCast: value doesn't fit in 120 bits");
        return uint120(value);
    }

    /**
     * @dev Returns the downcasted uint112 from uint256, reverting on
     * overflow (when the input is greater than largest uint112).
     *
     * Counterpart to Solidity's `uint112` operator.
     *
     * Requirements:
     *
     * - input must fit into 112 bits
     *
     * _Available since v4.7._
     */
    function toUint112(uint256 value) internal pure returns (uint112) {
        require(value <= type(uint112).max, "SafeCast: value doesn't fit in 112 bits");
        return uint112(value);
    }

    /**
     * @dev Returns the downcasted uint104 from uint256, reverting on
     * overflow (when the input is greater than largest uint104).
     *
     * Counterpart to Solidity's `uint104` operator.
     *
     * Requirements:
     *
     * - input must fit into 104 bits
     *
     * _Available since v4.7._
     */
    function toUint104(uint256 value) internal pure returns (uint104) {
        require(value <= type(uint104).max, "SafeCast: value doesn't fit in 104 bits");
        return uint104(value);
    }

    /**
     * @dev Returns the downcasted uint96 from uint256, reverting on
     * overflow (when the input is greater than largest uint96).
     *
     * Counterpart to Solidity's `uint96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     *
     * _Available since v4.2._
     */
    function toUint96(uint256 value) internal pure returns (uint96) {
        require(value <= type(uint96).max, "SafeCast: value doesn't fit in 96 bits");
        return uint96(value);
    }

    /**
     * @dev Returns the downcasted uint88 from uint256, reverting on
     * overflow (when the input is greater than largest uint88).
     *
     * Counterpart to Solidity's `uint88` operator.
     *
     * Requirements:
     *
     * - input must fit into 88 bits
     *
     * _Available since v4.7._
     */
    function toUint88(uint256 value) internal pure returns (uint88) {
        require(value <= type(uint88).max, "SafeCast: value doesn't fit in 88 bits");
        return uint88(value);
    }

    /**
     * @dev Returns the downcasted uint80 from uint256, reverting on
     * overflow (when the input is greater than largest uint80).
     *
     * Counterpart to Solidity's `uint80` operator.
     *
     * Requirements:
     *
     * - input must fit into 80 bits
     *
     * _Available since v4.7._
     */
    function toUint80(uint256 value) internal pure returns (uint80) {
        require(value <= type(uint80).max, "SafeCast: value doesn't fit in 80 bits");
        return uint80(value);
    }

    /**
     * @dev Returns the downcasted uint72 from uint256, reverting on
     * overflow (when the input is greater than largest uint72).
     *
     * Counterpart to Solidity's `uint72` operator.
     *
     * Requirements:
     *
     * - input must fit into 72 bits
     *
     * _Available since v4.7._
     */
    function toUint72(uint256 value) internal pure returns (uint72) {
        require(value <= type(uint72).max, "SafeCast: value doesn't fit in 72 bits");
        return uint72(value);
    }

    /**
     * @dev Returns the downcasted uint64 from uint256, reverting on
     * overflow (when the input is greater than largest uint64).
     *
     * Counterpart to Solidity's `uint64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v2.5._
     */
    function toUint64(uint256 value) internal pure returns (uint64) {
        require(value <= type(uint64).max, "SafeCast: value doesn't fit in 64 bits");
        return uint64(value);
    }

    /**
     * @dev Returns the downcasted uint56 from uint256, reverting on
     * overflow (when the input is greater than largest uint56).
     *
     * Counterpart to Solidity's `uint56` operator.
     *
     * Requirements:
     *
     * - input must fit into 56 bits
     *
     * _Available since v4.7._
     */
    function toUint56(uint256 value) internal pure returns (uint56) {
        require(value <= type(uint56).max, "SafeCast: value doesn't fit in 56 bits");
        return uint56(value);
    }

    /**
     * @dev Returns the downcasted uint48 from uint256, reverting on
     * overflow (when the input is greater than largest uint48).
     *
     * Counterpart to Solidity's `uint48` operator.
     *
     * Requirements:
     *
     * - input must fit into 48 bits
     *
     * _Available since v4.7._
     */
    function toUint48(uint256 value) internal pure returns (uint48) {
        require(value <= type(uint48).max, "SafeCast: value doesn't fit in 48 bits");
        return uint48(value);
    }

    /**
     * @dev Returns the downcasted uint40 from uint256, reverting on
     * overflow (when the input is greater than largest uint40).
     *
     * Counterpart to Solidity's `uint40` operator.
     *
     * Requirements:
     *
     * - input must fit into 40 bits
     *
     * _Available since v4.7._
     */
    function toUint40(uint256 value) internal pure returns (uint40) {
        require(value <= type(uint40).max, "SafeCast: value doesn't fit in 40 bits");
        return uint40(value);
    }

    /**
     * @dev Returns the downcasted uint32 from uint256, reverting on
     * overflow (when the input is greater than largest uint32).
     *
     * Counterpart to Solidity's `uint32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v2.5._
     */
    function toUint32(uint256 value) internal pure returns (uint32) {
        require(value <= type(uint32).max, "SafeCast: value doesn't fit in 32 bits");
        return uint32(value);
    }

    /**
     * @dev Returns the downcasted uint24 from uint256, reverting on
     * overflow (when the input is greater than largest uint24).
     *
     * Counterpart to Solidity's `uint24` operator.
     *
     * Requirements:
     *
     * - input must fit into 24 bits
     *
     * _Available since v4.7._
     */
    function toUint24(uint256 value) internal pure returns (uint24) {
        require(value <= type(uint24).max, "SafeCast: value doesn't fit in 24 bits");
        return uint24(value);
    }

    /**
     * @dev Returns the downcasted uint16 from uint256, reverting on
     * overflow (when the input is greater than largest uint16).
     *
     * Counterpart to Solidity's `uint16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v2.5._
     */
    function toUint16(uint256 value) internal pure returns (uint16) {
        require(value <= type(uint16).max, "SafeCast: value doesn't fit in 16 bits");
        return uint16(value);
    }

    /**
     * @dev Returns the downcasted uint8 from uint256, reverting on
     * overflow (when the input is greater than largest uint8).
     *
     * Counterpart to Solidity's `uint8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits
     *
     * _Available since v2.5._
     */
    function toUint8(uint256 value) internal pure returns (uint8) {
        require(value <= type(uint8).max, "SafeCast: value doesn't fit in 8 bits");
        return uint8(value);
    }

    /**
     * @dev Converts a signed int256 into an unsigned uint256.
     *
     * Requirements:
     *
     * - input must be greater than or equal to 0.
     *
     * _Available since v3.0._
     */
    function toUint256(int256 value) internal pure returns (uint256) {
        require(value >= 0, "SafeCast: value must be positive");
        return uint256(value);
    }

    /**
     * @dev Returns the downcasted int248 from int256, reverting on
     * overflow (when the input is less than smallest int248 or
     * greater than largest int248).
     *
     * Counterpart to Solidity's `int248` operator.
     *
     * Requirements:
     *
     * - input must fit into 248 bits
     *
     * _Available since v4.7._
     */
    function toInt248(int256 value) internal pure returns (int248 downcasted) {
        downcasted = int248(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 248 bits");
    }

    /**
     * @dev Returns the downcasted int240 from int256, reverting on
     * overflow (when the input is less than smallest int240 or
     * greater than largest int240).
     *
     * Counterpart to Solidity's `int240` operator.
     *
     * Requirements:
     *
     * - input must fit into 240 bits
     *
     * _Available since v4.7._
     */
    function toInt240(int256 value) internal pure returns (int240 downcasted) {
        downcasted = int240(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 240 bits");
    }

    /**
     * @dev Returns the downcasted int232 from int256, reverting on
     * overflow (when the input is less than smallest int232 or
     * greater than largest int232).
     *
     * Counterpart to Solidity's `int232` operator.
     *
     * Requirements:
     *
     * - input must fit into 232 bits
     *
     * _Available since v4.7._
     */
    function toInt232(int256 value) internal pure returns (int232 downcasted) {
        downcasted = int232(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 232 bits");
    }

    /**
     * @dev Returns the downcasted int224 from int256, reverting on
     * overflow (when the input is less than smallest int224 or
     * greater than largest int224).
     *
     * Counterpart to Solidity's `int224` operator.
     *
     * Requirements:
     *
     * - input must fit into 224 bits
     *
     * _Available since v4.7._
     */
    function toInt224(int256 value) internal pure returns (int224 downcasted) {
        downcasted = int224(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 224 bits");
    }

    /**
     * @dev Returns the downcasted int216 from int256, reverting on
     * overflow (when the input is less than smallest int216 or
     * greater than largest int216).
     *
     * Counterpart to Solidity's `int216` operator.
     *
     * Requirements:
     *
     * - input must fit into 216 bits
     *
     * _Available since v4.7._
     */
    function toInt216(int256 value) internal pure returns (int216 downcasted) {
        downcasted = int216(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 216 bits");
    }

    /**
     * @dev Returns the downcasted int208 from int256, reverting on
     * overflow (when the input is less than smallest int208 or
     * greater than largest int208).
     *
     * Counterpart to Solidity's `int208` operator.
     *
     * Requirements:
     *
     * - input must fit into 208 bits
     *
     * _Available since v4.7._
     */
    function toInt208(int256 value) internal pure returns (int208 downcasted) {
        downcasted = int208(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 208 bits");
    }

    /**
     * @dev Returns the downcasted int200 from int256, reverting on
     * overflow (when the input is less than smallest int200 or
     * greater than largest int200).
     *
     * Counterpart to Solidity's `int200` operator.
     *
     * Requirements:
     *
     * - input must fit into 200 bits
     *
     * _Available since v4.7._
     */
    function toInt200(int256 value) internal pure returns (int200 downcasted) {
        downcasted = int200(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 200 bits");
    }

    /**
     * @dev Returns the downcasted int192 from int256, reverting on
     * overflow (when the input is less than smallest int192 or
     * greater than largest int192).
     *
     * Counterpart to Solidity's `int192` operator.
     *
     * Requirements:
     *
     * - input must fit into 192 bits
     *
     * _Available since v4.7._
     */
    function toInt192(int256 value) internal pure returns (int192 downcasted) {
        downcasted = int192(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 192 bits");
    }

    /**
     * @dev Returns the downcasted int184 from int256, reverting on
     * overflow (when the input is less than smallest int184 or
     * greater than largest int184).
     *
     * Counterpart to Solidity's `int184` operator.
     *
     * Requirements:
     *
     * - input must fit into 184 bits
     *
     * _Available since v4.7._
     */
    function toInt184(int256 value) internal pure returns (int184 downcasted) {
        downcasted = int184(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 184 bits");
    }

    /**
     * @dev Returns the downcasted int176 from int256, reverting on
     * overflow (when the input is less than smallest int176 or
     * greater than largest int176).
     *
     * Counterpart to Solidity's `int176` operator.
     *
     * Requirements:
     *
     * - input must fit into 176 bits
     *
     * _Available since v4.7._
     */
    function toInt176(int256 value) internal pure returns (int176 downcasted) {
        downcasted = int176(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 176 bits");
    }

    /**
     * @dev Returns the downcasted int168 from int256, reverting on
     * overflow (when the input is less than smallest int168 or
     * greater than largest int168).
     *
     * Counterpart to Solidity's `int168` operator.
     *
     * Requirements:
     *
     * - input must fit into 168 bits
     *
     * _Available since v4.7._
     */
    function toInt168(int256 value) internal pure returns (int168 downcasted) {
        downcasted = int168(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 168 bits");
    }

    /**
     * @dev Returns the downcasted int160 from int256, reverting on
     * overflow (when the input is less than smallest int160 or
     * greater than largest int160).
     *
     * Counterpart to Solidity's `int160` operator.
     *
     * Requirements:
     *
     * - input must fit into 160 bits
     *
     * _Available since v4.7._
     */
    function toInt160(int256 value) internal pure returns (int160 downcasted) {
        downcasted = int160(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 160 bits");
    }

    /**
     * @dev Returns the downcasted int152 from int256, reverting on
     * overflow (when the input is less than smallest int152 or
     * greater than largest int152).
     *
     * Counterpart to Solidity's `int152` operator.
     *
     * Requirements:
     *
     * - input must fit into 152 bits
     *
     * _Available since v4.7._
     */
    function toInt152(int256 value) internal pure returns (int152 downcasted) {
        downcasted = int152(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 152 bits");
    }

    /**
     * @dev Returns the downcasted int144 from int256, reverting on
     * overflow (when the input is less than smallest int144 or
     * greater than largest int144).
     *
     * Counterpart to Solidity's `int144` operator.
     *
     * Requirements:
     *
     * - input must fit into 144 bits
     *
     * _Available since v4.7._
     */
    function toInt144(int256 value) internal pure returns (int144 downcasted) {
        downcasted = int144(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 144 bits");
    }

    /**
     * @dev Returns the downcasted int136 from int256, reverting on
     * overflow (when the input is less than smallest int136 or
     * greater than largest int136).
     *
     * Counterpart to Solidity's `int136` operator.
     *
     * Requirements:
     *
     * - input must fit into 136 bits
     *
     * _Available since v4.7._
     */
    function toInt136(int256 value) internal pure returns (int136 downcasted) {
        downcasted = int136(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 136 bits");
    }

    /**
     * @dev Returns the downcasted int128 from int256, reverting on
     * overflow (when the input is less than smallest int128 or
     * greater than largest int128).
     *
     * Counterpart to Solidity's `int128` operator.
     *
     * Requirements:
     *
     * - input must fit into 128 bits
     *
     * _Available since v3.1._
     */
    function toInt128(int256 value) internal pure returns (int128 downcasted) {
        downcasted = int128(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 128 bits");
    }

    /**
     * @dev Returns the downcasted int120 from int256, reverting on
     * overflow (when the input is less than smallest int120 or
     * greater than largest int120).
     *
     * Counterpart to Solidity's `int120` operator.
     *
     * Requirements:
     *
     * - input must fit into 120 bits
     *
     * _Available since v4.7._
     */
    function toInt120(int256 value) internal pure returns (int120 downcasted) {
        downcasted = int120(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 120 bits");
    }

    /**
     * @dev Returns the downcasted int112 from int256, reverting on
     * overflow (when the input is less than smallest int112 or
     * greater than largest int112).
     *
     * Counterpart to Solidity's `int112` operator.
     *
     * Requirements:
     *
     * - input must fit into 112 bits
     *
     * _Available since v4.7._
     */
    function toInt112(int256 value) internal pure returns (int112 downcasted) {
        downcasted = int112(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 112 bits");
    }

    /**
     * @dev Returns the downcasted int104 from int256, reverting on
     * overflow (when the input is less than smallest int104 or
     * greater than largest int104).
     *
     * Counterpart to Solidity's `int104` operator.
     *
     * Requirements:
     *
     * - input must fit into 104 bits
     *
     * _Available since v4.7._
     */
    function toInt104(int256 value) internal pure returns (int104 downcasted) {
        downcasted = int104(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 104 bits");
    }

    /**
     * @dev Returns the downcasted int96 from int256, reverting on
     * overflow (when the input is less than smallest int96 or
     * greater than largest int96).
     *
     * Counterpart to Solidity's `int96` operator.
     *
     * Requirements:
     *
     * - input must fit into 96 bits
     *
     * _Available since v4.7._
     */
    function toInt96(int256 value) internal pure returns (int96 downcasted) {
        downcasted = int96(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 96 bits");
    }

    /**
     * @dev Returns the downcasted int88 from int256, reverting on
     * overflow (when the input is less than smallest int88 or
     * greater than largest int88).
     *
     * Counterpart to Solidity's `int88` operator.
     *
     * Requirements:
     *
     * - input must fit into 88 bits
     *
     * _Available since v4.7._
     */
    function toInt88(int256 value) internal pure returns (int88 downcasted) {
        downcasted = int88(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 88 bits");
    }

    /**
     * @dev Returns the downcasted int80 from int256, reverting on
     * overflow (when the input is less than smallest int80 or
     * greater than largest int80).
     *
     * Counterpart to Solidity's `int80` operator.
     *
     * Requirements:
     *
     * - input must fit into 80 bits
     *
     * _Available since v4.7._
     */
    function toInt80(int256 value) internal pure returns (int80 downcasted) {
        downcasted = int80(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 80 bits");
    }

    /**
     * @dev Returns the downcasted int72 from int256, reverting on
     * overflow (when the input is less than smallest int72 or
     * greater than largest int72).
     *
     * Counterpart to Solidity's `int72` operator.
     *
     * Requirements:
     *
     * - input must fit into 72 bits
     *
     * _Available since v4.7._
     */
    function toInt72(int256 value) internal pure returns (int72 downcasted) {
        downcasted = int72(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 72 bits");
    }

    /**
     * @dev Returns the downcasted int64 from int256, reverting on
     * overflow (when the input is less than smallest int64 or
     * greater than largest int64).
     *
     * Counterpart to Solidity's `int64` operator.
     *
     * Requirements:
     *
     * - input must fit into 64 bits
     *
     * _Available since v3.1._
     */
    function toInt64(int256 value) internal pure returns (int64 downcasted) {
        downcasted = int64(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 64 bits");
    }

    /**
     * @dev Returns the downcasted int56 from int256, reverting on
     * overflow (when the input is less than smallest int56 or
     * greater than largest int56).
     *
     * Counterpart to Solidity's `int56` operator.
     *
     * Requirements:
     *
     * - input must fit into 56 bits
     *
     * _Available since v4.7._
     */
    function toInt56(int256 value) internal pure returns (int56 downcasted) {
        downcasted = int56(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 56 bits");
    }

    /**
     * @dev Returns the downcasted int48 from int256, reverting on
     * overflow (when the input is less than smallest int48 or
     * greater than largest int48).
     *
     * Counterpart to Solidity's `int48` operator.
     *
     * Requirements:
     *
     * - input must fit into 48 bits
     *
     * _Available since v4.7._
     */
    function toInt48(int256 value) internal pure returns (int48 downcasted) {
        downcasted = int48(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 48 bits");
    }

    /**
     * @dev Returns the downcasted int40 from int256, reverting on
     * overflow (when the input is less than smallest int40 or
     * greater than largest int40).
     *
     * Counterpart to Solidity's `int40` operator.
     *
     * Requirements:
     *
     * - input must fit into 40 bits
     *
     * _Available since v4.7._
     */
    function toInt40(int256 value) internal pure returns (int40 downcasted) {
        downcasted = int40(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 40 bits");
    }

    /**
     * @dev Returns the downcasted int32 from int256, reverting on
     * overflow (when the input is less than smallest int32 or
     * greater than largest int32).
     *
     * Counterpart to Solidity's `int32` operator.
     *
     * Requirements:
     *
     * - input must fit into 32 bits
     *
     * _Available since v3.1._
     */
    function toInt32(int256 value) internal pure returns (int32 downcasted) {
        downcasted = int32(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 32 bits");
    }

    /**
     * @dev Returns the downcasted int24 from int256, reverting on
     * overflow (when the input is less than smallest int24 or
     * greater than largest int24).
     *
     * Counterpart to Solidity's `int24` operator.
     *
     * Requirements:
     *
     * - input must fit into 24 bits
     *
     * _Available since v4.7._
     */
    function toInt24(int256 value) internal pure returns (int24 downcasted) {
        downcasted = int24(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 24 bits");
    }

    /**
     * @dev Returns the downcasted int16 from int256, reverting on
     * overflow (when the input is less than smallest int16 or
     * greater than largest int16).
     *
     * Counterpart to Solidity's `int16` operator.
     *
     * Requirements:
     *
     * - input must fit into 16 bits
     *
     * _Available since v3.1._
     */
    function toInt16(int256 value) internal pure returns (int16 downcasted) {
        downcasted = int16(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 16 bits");
    }

    /**
     * @dev Returns the downcasted int8 from int256, reverting on
     * overflow (when the input is less than smallest int8 or
     * greater than largest int8).
     *
     * Counterpart to Solidity's `int8` operator.
     *
     * Requirements:
     *
     * - input must fit into 8 bits
     *
     * _Available since v3.1._
     */
    function toInt8(int256 value) internal pure returns (int8 downcasted) {
        downcasted = int8(value);
        require(downcasted == value, "SafeCast: value doesn't fit in 8 bits");
    }

    /**
     * @dev Converts an unsigned uint256 into a signed int256.
     *
     * Requirements:
     *
     * - input must be less than or equal to maxInt256.
     *
     * _Available since v3.0._
     */
    function toInt256(uint256 value) internal pure returns (int256) {
        // Note: Unsafe cast below is okay because `type(int256).max` is guaranteed to be positive
        require(value <= uint256(type(int256).max), "SafeCast: value doesn't fit in an int256");
        return int256(value);
    }
}