/**
 *Submitted for verification at Etherscan.io on 2020-10-30
*/

/**
 *Submitted for verification at Etherscan.io on 2020-10-30
*/

// SPDX-License-Identifier: UNLICENSED
pragma solidity ^0.6.12;

/**
 * @dev Wrappers over Solidity's arithmetic operations with added overflow
 * checks.
 *
 * Arithmetic operations in Solidity wrap on overflow. This can easily result
 * in bugs, because programmers usually assume that an overflow raises an
 * error, which is the standard behavior in high level programming languages.
 * `SafeMath` restores this intuition by reverting the transaction when 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.
 */
library SafeMath {
    /**
     * @dev Returns the addition of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `+` operator.
     *
     * Requirements:
     *
     * - Addition cannot overflow.
     */
    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        require(c >= a, "SafeMath: addition overflow");

        return c;
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        return sub(a, b, "SafeMath: subtraction overflow");
    }

    /**
     * @dev Returns the subtraction of two unsigned integers, reverting with custom message on
     * overflow (when the result is negative).
     *
     * Counterpart to Solidity's `-` operator.
     *
     * Requirements:
     *
     * - Subtraction cannot overflow.
     */
    function sub(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b <= a, errorMessage);
        uint256 c = a - b;

        return c;
    }

    /**
     * @dev Returns the multiplication of two unsigned integers, reverting on
     * overflow.
     *
     * Counterpart to Solidity's `*` operator.
     *
     * Requirements:
     *
     * - Multiplication cannot overflow.
     */
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        // Gas optimization: this is cheaper than requiring 'a' not being zero, but the
        // benefit is lost if 'b' is also tested.
        // See: https://github.com/OpenZeppelin/openzeppelin-contracts/pull/522
        if (a == 0) {
            return 0;
        }

        uint256 c = a * b;
        require(c / a == b, "SafeMath: multiplication overflow");

        return c;
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        return div(a, b, "SafeMath: division by zero");
    }

    /**
     * @dev Returns the integer division of two unsigned integers. Reverts with custom message on
     * division by zero. The result is rounded towards zero.
     *
     * Counterpart to Solidity's `/` operator. Note: this function uses a
     * `revert` opcode (which leaves remaining gas untouched) while Solidity
     * uses an invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function div(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b > 0, errorMessage);
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold

        return c;
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b) internal pure returns (uint256) {
        return mod(a, b, "SafeMath: modulo by zero");
    }

    /**
     * @dev Returns the remainder of dividing two unsigned integers. (unsigned integer modulo),
     * Reverts with custom message when dividing by zero.
     *
     * Counterpart to Solidity's `%` operator. This function uses a `revert`
     * opcode (which leaves remaining gas untouched) while Solidity uses an
     * invalid opcode to revert (consuming all remaining gas).
     *
     * Requirements:
     *
     * - The divisor cannot be zero.
     */
    function mod(uint256 a, uint256 b, string memory errorMessage) internal pure returns (uint256) {
        require(b != 0, errorMessage);
        return a % b;
    }
}

abstract contract Context {
    function _msgSender() internal view virtual returns (address payable) {
        return msg.sender;
    }

    function _msgData() internal view virtual returns (bytes memory) {
        this; // silence state mutability warning without generating bytecode - see https://github.com/ethereum/solidity/issues/2691
        return msg.data;
    }
}

contract Ownable is Context {
    address private _owner;

    event OwnershipTransferred(address indexed previousOwner, address indexed newOwner);

    /**
     * @dev Initializes the contract setting the deployer as the initial owner.
     */
    constructor () internal {
        address msgSender = _msgSender();
        _owner = msgSender;
        emit OwnershipTransferred(address(0), msgSender);
    }

    /**
     * @dev Returns the address of the current owner.
     */
    function owner() public view returns (address) {
        return _owner;
    }

    /**
     * @dev Throws if called by any account other than the owner.
     */
    modifier onlyOwner() {
        require(_owner == _msgSender(), "Ownable: caller is not the owner");
        _;
    }

    /**
     * @dev Leaves the contract without owner. It will not be possible to call
     * `onlyOwner` functions anymore. Can only be called by the current owner.
     *
     * NOTE: Renouncing ownership will leave the contract without an owner,
     * thereby removing any functionality that is only available to the owner.
     */
    function renounceOwnership() public virtual onlyOwner {
        emit OwnershipTransferred(_owner, address(0));
        _owner = address(0);
    }

    /**
     * @dev Transfers ownership of the contract to a new account (`newOwner`).
     * Can only be called by the current owner.
     */
    function transferOwnership(address newOwner) public virtual onlyOwner {
        require(newOwner != address(0), "Ownable: new owner is the zero address");
        emit OwnershipTransferred(_owner, newOwner);
        _owner = newOwner;
    }
}

library Address {
    /**
     * @dev Returns true if `account` is a contract.
     *
     * [IMPORTANT]
     * ====
     * It is unsafe to assume that an address for which this function returns
     * false is an externally-owned account (EOA) and not a contract.
     *
     * Among others, `isContract` will return false for the following
     * types of addresses:
     *
     *  - an externally-owned account
     *  - a contract in construction
     *  - an address where a contract will be created
     *  - an address where a contract lived, but was destroyed
     * ====
     */
    function isContract(address account) internal view returns (bool) {
        // According to EIP-1052, 0x0 is the value returned for not-yet created accounts
        // and 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470 is returned
        // for accounts without code, i.e. `keccak256('')`
        bytes32 codehash;
        bytes32 accountHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
        // solhint-disable-next-line no-inline-assembly
        assembly { codehash := extcodehash(account) }
        return (codehash != accountHash && codehash != 0x0);
    }

    /**
     * @dev Replacement for Solidity's `transfer`: sends `amount` wei to
     * `recipient`, forwarding all available gas and reverting on errors.
     *
     * https://eips.ethereum.org/EIPS/eip-1884[EIP1884] increases the gas cost
     * of certain opcodes, possibly making contracts go over the 2300 gas limit
     * imposed by `transfer`, making them unable to receive funds via
     * `transfer`. {sendValue} removes this limitation.
     *
     * https://diligence.consensys.net/posts/2019/09/stop-using-soliditys-transfer-now/[Learn more].
     *
     * IMPORTANT: because control is transferred to `recipient`, care must be
     * taken to not create reentrancy vulnerabilities. Consider using
     * {ReentrancyGuard} or the
     * https://solidity.readthedocs.io/en/v0.5.11/security-considerations.html#use-the-checks-effects-interactions-pattern[checks-effects-interactions pattern].
     */
    function sendValue(address payable recipient, uint256 amount) internal {
        require(address(this).balance >= amount, "Address: insufficient balance");

        // solhint-disable-next-line avoid-low-level-calls, avoid-call-value
        (bool success, ) = recipient.call{ value: amount }("");
        require(success, "Address: unable to send value, recipient may have reverted");
    }

    /**
     * @dev Performs a Solidity function call using a low level `call`. A
     * plain`call` is an unsafe replacement for a function call: use this
     * function instead.
     *
     * If `target` reverts with a revert reason, it is bubbled up by this
     * function (like regular Solidity function calls).
     *
     * Returns the raw returned data. To convert to the expected return value,
     * use https://solidity.readthedocs.io/en/latest/units-and-global-variables.html?highlight=abi.decode#abi-encoding-and-decoding-functions[`abi.decode`].
     *
     * Requirements:
     *
     * - `target` must be a contract.
     * - calling `target` with `data` must not revert.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data) internal returns (bytes memory) {
        return functionCall(target, data, "Address: low-level call failed");
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`], but with
     * `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCall(address target, bytes memory data, string memory errorMessage) internal returns (bytes memory) {
        return _functionCallWithValue(target, data, 0, errorMessage);
    }

    /**
     * @dev Same as {xref-Address-functionCall-address-bytes-}[`functionCall`],
     * but also transferring `value` wei to `target`.
     *
     * Requirements:
     *
     * - the calling contract must have an ETH balance of at least `value`.
     * - the called Solidity function must be `payable`.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value) internal returns (bytes memory) {
        return functionCallWithValue(target, data, value, "Address: low-level call with value failed");
    }

    /**
     * @dev Same as {xref-Address-functionCallWithValue-address-bytes-uint256-}[`functionCallWithValue`], but
     * with `errorMessage` as a fallback revert reason when `target` reverts.
     *
     * _Available since v3.1._
     */
    function functionCallWithValue(address target, bytes memory data, uint256 value, string memory errorMessage) internal returns (bytes memory) {
        require(address(this).balance >= value, "Address: insufficient balance for call");
        return _functionCallWithValue(target, data, value, errorMessage);
    }

    function _functionCallWithValue(address target, bytes memory data, uint256 weiValue, string memory errorMessage) private returns (bytes memory) {
        require(isContract(target), "Address: call to non-contract");

        // solhint-disable-next-line avoid-low-level-calls
        (bool success, bytes memory returndata) = target.call{ value: weiValue }(data);
        if (success) {
            return returndata;
        } else {
            // Look for revert reason and bubble it up if present
            if (returndata.length > 0) {
                // The easiest way to bubble the revert reason is using memory via assembly

                // solhint-disable-next-line no-inline-assembly
                assembly {
                    let returndata_size := mload(returndata)
                    revert(add(32, returndata), returndata_size)
                }
            } else {
                revert(errorMessage);
            }
        }
    }
}

/*
    Copyright 2016, Adrià Massanet

    This program is 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.

    This program 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 this program.  If not, see <http://www.gnu.org/licenses/>.

    Checked results with FIPS test vectors
    https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Algorithm-Validation-Program/documents/dss/186-2rsatestvectors.zip
    file SigVer15_186-3.rsp

 */
contract SolRsaVerify {

    function memcpy(uint _dest, uint _src, uint _len) pure internal {
        // Copy word-length chunks while possible
        for ( ;_len >= 32; _len -= 32) {
            assembly {
                mstore(_dest, mload(_src))
            }
            _dest += 32;
            _src += 32;
        }

        // Copy remaining bytes
        uint mask = 256 ** (32 - _len) - 1;
        assembly {
            let srcpart := and(mload(_src), not(mask))
            let destpart := and(mload(_dest), mask)
            mstore(_dest, or(destpart, srcpart))
        }
    }


    function join(
        bytes memory _s, bytes memory _e, bytes memory _m
    ) pure internal returns (bytes memory) {
        uint inputLen = 0x60+_s.length+_e.length+_m.length;

        uint slen = _s.length;
        uint elen = _e.length;
        uint mlen = _m.length;
        uint sptr;
        uint eptr;
        uint mptr;
        uint inputPtr;

        bytes memory input = new bytes(inputLen);
        assembly {
            sptr := add(_s,0x20)
            eptr := add(_e,0x20)
            mptr := add(_m,0x20)
            mstore(add(input,0x20),slen)
            mstore(add(input,0x40),elen)
            mstore(add(input,0x60),mlen)
            inputPtr := add(input,0x20)
        }
        memcpy(inputPtr+0x60,sptr,_s.length);
        memcpy(inputPtr+0x60+_s.length,eptr,_e.length);
        memcpy(inputPtr+0x60+_s.length+_e.length,mptr,_m.length);

        return input;
    }

    /** @dev Verifies a PKCSv1.5 SHA256 signature
      * @param _sha256 is the sha256 of the data
      * @param _s is the signature
      * @param _e is the exponent
      * @param _m is the modulus
      * @return 0 if success, >0 otherwise
    */
    function pkcs1Sha256Verify(
        bytes32 _sha256,
        bytes memory _s, bytes memory _e, bytes memory _m
    ) public view returns (uint) {

        uint8[19] memory sha256Prefix = [
        0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, 0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, 0x05, 0x00, 0x04, 0x20
        ];

        require(_m.length >= sha256Prefix.length+_sha256.length+11);

        uint i;

        /// decipher
        bytes memory input = join(_s,_e,_m);
        uint inputlen = input.length;

        uint decipherlen = _m.length;
        bytes memory decipher = new bytes(decipherlen);
        assembly {
            pop(staticcall(sub(gas(), 2000), 5, add(input,0x20), inputlen, add(decipher,0x20), decipherlen))
        }

        /// 0x00 || 0x01 || PS || 0x00 || DigestInfo
        /// PS is padding filled with 0xff
        //  DigestInfo ::= SEQUENCE {
        //     digestAlgorithm AlgorithmIdentifier,
        //     digest OCTET STRING
        //  }

        uint paddingLen = decipherlen - 3 - sha256Prefix.length - 32;

        if (decipher[0] != 0 || uint8(decipher[1]) != 1) {
            return 1;
        }
        for (i = 2;i<2+paddingLen;i++) {
            if (decipher[i] != 0xff) {
                return 2;
            }
        }
        if (decipher[2+paddingLen] != 0) {
            return 3;
        }
        for (i = 0;i<sha256Prefix.length;i++) {
            if (uint8(decipher[3+paddingLen+i])!=sha256Prefix[i]) {
                return 4;
            }
        }
        for (i = 0;i<_sha256.length;i++) {
            if (decipher[3+paddingLen+sha256Prefix.length+i]!=_sha256[i]) {
                return 5;
            }
        }

        return 0;
    }

    /** @dev Verifies a PKCSv1.5 SHA256 signature
      * @param _data to verify
      * @param _s is the signature
      * @param _e is the exponent
      * @param _m is the modulus
      * @return 0 if success, >0 otherwise
    */
    function pkcs1Sha256VerifyRaw(
        bytes memory _data,
        bytes memory _s, bytes memory _e, bytes memory _m
    ) public view returns (uint) {
        return pkcs1Sha256Verify(sha256(_data),_s,_e,_m);
    }

}

interface IERC20 {
    /**
     * @dev Returns the amount of tokens in existence.
     */
    function totalSupply() external view returns (uint256);

    /**
     * @dev Returns the amount of tokens owned by `account`.
     */
    function balanceOf(address account) external view returns (uint256);

    /**
     * @dev Moves `amount` tokens from the caller's account to `recipient`.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transfer(address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Returns the remaining number of tokens that `spender` will be
     * allowed to spend on behalf of `owner` through {transferFrom}. This is
     * zero by default.
     *
     * This value changes when {approve} or {transferFrom} are called.
     */
    function allowance(address owner, address spender) external view returns (uint256);

    /**
     * @dev Sets `amount` as the allowance of `spender` over the caller's tokens.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * IMPORTANT: Beware that changing an allowance with this method brings the risk
     * that someone may use both the old and the new allowance by unfortunate
     * transaction ordering. One possible solution to mitigate this race
     * condition is to first reduce the spender's allowance to 0 and set the
     * desired value afterwards:
     * https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729
     *
     * Emits an {Approval} event.
     */
    function approve(address spender, uint256 amount) external returns (bool);

    /**
     * @dev Moves `amount` tokens from `sender` to `recipient` using the
     * allowance mechanism. `amount` is then deducted from the caller's
     * allowance.
     *
     * Returns a boolean value indicating whether the operation succeeded.
     *
     * Emits a {Transfer} event.
     */
    function transferFrom(address sender, address recipient, uint256 amount) external returns (bool);

    /**
     * @dev Emitted when `value` tokens are moved from one account (`from`) to
     * another (`to`).
     *
     * Note that `value` may be zero.
     */
    event Transfer(address indexed from, address indexed to, uint256 value);

    /**
     * @dev Emitted when the allowance of a `spender` for an `owner` is set by
     * a call to {approve}. `value` is the new allowance.
     */
    event Approval(address indexed owner, address indexed spender, uint256 value);
}

library SafeERC20 {
    using SafeMath for uint256;
    using Address for address;

    function safeTransfer(IERC20 token, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transfer.selector, to, value));
    }

    function safeTransferFrom(IERC20 token, address from, address to, uint256 value) internal {
        _callOptionalReturn(token, abi.encodeWithSelector(token.transferFrom.selector, from, to, value));
    }

    /**
     * @dev Deprecated. This function has issues similar to the ones found in
     * {IERC20-approve}, and its usage is discouraged.
     *
     * Whenever possible, use {safeIncreaseAllowance} and
     * {safeDecreaseAllowance} instead.
     */
    function safeApprove(IERC20 token, address spender, uint256 value) internal {
        // safeApprove should only be called when setting an initial allowance,
        // or when resetting it to zero. To increase and decrease it, use
        // 'safeIncreaseAllowance' and 'safeDecreaseAllowance'
        // solhint-disable-next-line max-line-length
        require((value == 0) || (token.allowance(address(this), spender) == 0),
            "SafeERC20: approve from non-zero to non-zero allowance"
        );
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, value));
    }

    function safeIncreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).add(value);
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    function safeDecreaseAllowance(IERC20 token, address spender, uint256 value) internal {
        uint256 newAllowance = token.allowance(address(this), spender).sub(value, "SafeERC20: decreased allowance below zero");
        _callOptionalReturn(token, abi.encodeWithSelector(token.approve.selector, spender, newAllowance));
    }

    /**
     * @dev Imitates a Solidity high-level call (i.e. a regular function call to a contract), relaxing the requirement
     * on the return value: the return value is optional (but if data is returned, it must not be false).
     * @param token The token targeted by the call.
     * @param data The call data (encoded using abi.encode or one of its variants).
     */
    function _callOptionalReturn(IERC20 token, bytes memory data) private {
        // We need to perform a low level call here, to bypass Solidity's return data size checking mechanism, since
        // we're implementing it ourselves. We use {Address.functionCall} to perform this call, which verifies that
        // the target address contains contract code and also asserts for success in the low-level call.

        bytes memory returndata = address(token).functionCall(data, "SafeERC20: low-level call failed");
        if (returndata.length > 0) { // Return data is optional
            // solhint-disable-next-line max-line-length
            require(abi.decode(returndata, (bool)), "SafeERC20: ERC20 operation did not succeed");
        }
    }
}

interface IMilk2Token {

    function mint(address _to, uint256 _amount) external returns (bool);

    function burn(address _to, uint256 _amount) external returns (bool);

}

contract MultiplierMath {

    function max(uint256 a, uint256 b) internal pure returns (uint256) {
        return a > b ? a : b;
    }


    function min(uint256 a, uint256 b) internal pure returns (uint256) {
        return a < b ? a : b;
    }


    function getInterval(uint256 a, uint256 b) internal pure returns(uint256) {
        return a > b ? a - b : 0;
    }

}

contract ShadowStaking is Ownable, SolRsaVerify, MultiplierMath {
    using SafeMath for uint256;
    using SafeERC20 for IERC20;

    struct UserInfo {
        uint256 rewardDebt;
        uint256 lastBlock;
    }


    struct PoolInfo {
        IERC20 lpToken;
        uint256 allocPointAmount;
        uint256 blockCreation;
    }


    struct KeyInfo{
        bytes keyModule;
        bytes exponent;
        bool keyStatus;
    }

    IMilk2Token public milk;

    mapping (address => UserInfo) private userInfo;

    address[] internal users;


    PoolInfo[] private poolInfo;

    KeyInfo[] private keyInfo;


    uint256 private totalPoints;

    uint256[5] internal epochs;

    uint256[5] internal multipliers;


    event Harvest(address sender, uint256 amount, uint256 blockNumber);
    event AddNewPool(address token, uint256 pid);
    event PoolUpdate(uint256 poolPid, uint256 previusPoints, uint256 newPoints);
    event AddNewKey(bytes keyHash, uint256 id);


    constructor(IMilk2Token _milk, uint256[5] memory _epochs, uint256[5] memory _multipliers) public {
        milk = _milk;
        epochs = _epochs;
        multipliers = _multipliers;
    }


    /**
      * @dev Add a new lp to the pool.
      *
      * @param _lpToken - address of ERC-20 LP token
       * @param _newPoints - share in the total amount of rewards
      * DO NOT add the same LP token more than once. Rewards will be messed up if you do.
      * Can only be called by the current owner.
      */
    function addNewPool(IERC20 _lpToken, uint256 _newPoints) public onlyOwner {
        totalPoints = totalPoints.add(_newPoints);
        poolInfo.push(PoolInfo({lpToken: _lpToken, allocPointAmount: _newPoints, blockCreation:block.number}));
        emit AddNewPool(address(_lpToken), _newPoints);
    }


    /**
     * @dev Update lp address to the pool.
     *
     * @param _poolPid - number of pool
     * @param _newPoints - new amount of allocation points
     * DO NOT add the same LP token more than once. Rewards will be messed up if you do.
     * Can only be called by the current owner.
     */
    function setPoll(uint256 _poolPid, uint256 _newPoints) public onlyOwner {
        PoolInfo memory _poolInfo = poolInfo[_poolPid];
        uint256 _previousPoints = poolInfo[_poolPid].allocPointAmount;
        _poolInfo.allocPointAmount = _newPoints;

        totalPoints = totalPoints.sub(poolInfo[_poolPid].allocPointAmount).add(_newPoints);
        emit PoolUpdate(_poolPid, _previousPoints, _newPoints);
    }


    function getPool(uint256 _poolPid) public view returns(address _lpToken, uint256 _block, uint256 _weight) {
        PoolInfo memory _poolInfo = poolInfo[_poolPid];
        _lpToken = address(_poolInfo.lpToken);
        _block = _poolInfo.blockCreation;
        _weight = _poolInfo.allocPointAmount;
    }


    /**
      * @dev - return Number of keys
      */
    function getPoolsCount() public view returns(uint256) {
        return poolInfo.length;
    }


    /**
      * @dev - return info about current user's reward
      * @param _user - user's address
      */
    function getRewards(address _user) public view returns(uint256) {
        return  userInfo[_user].rewardDebt;
    }


    /**
      * @dev - return info about user's last block with update
      *
      * @param _user - user's address
      */
    function getLastBlock(address _user) public view returns(uint256) {
        return userInfo[_user].lastBlock;
    }


    /**
    * @dev - return total allocation points
    */
    function getTotalPoints() public view returns(uint256) {
        return totalPoints;
    }


    /**
      * @dev Update the given pool's allocation point. Can only be called by the owner.
      *
      * @param _keyId - unique id key in contract storage
      * @param _amount -
      * @param _lastBlockNumber - last update number of block
      * @param _currentBlockNumber - last update block in Ethereum mainnet
      * @param _sign - bytes32 signature
      */
    function withdraw(  uint256 _keyId,
                        uint256 _amount,
                        uint256 _lastBlockNumber,
                        uint256 _currentBlockNumber,
                        bytes memory _sign) public {
        require(_keyId < keyInfo.length, "This key is not exist");
        require(keyInfo[_keyId].keyStatus, "This key is disable");
        require(_currentBlockNumber < block.number, "currentBlockNumber cannot be larger than the last block");
        require(pkcs1Sha256Verify(getData(_amount, _lastBlockNumber, _currentBlockNumber, msg.sender), _sign, keyInfo[_keyId].exponent, keyInfo[_keyId].keyModule) == 0, "Incorrect data");
        require(userInfo[msg.sender].lastBlock == _lastBlockNumber, "lastBlockNumber must be equal to the value in the storage");

        userInfo[msg.sender].rewardDebt = userInfo[msg.sender].rewardDebt.add(_amount);
        userInfo[msg.sender].lastBlock = _currentBlockNumber;
        if (_amount > 0) {
            milk.mint(msg.sender, _amount);
        }
        emit Harvest(msg.sender, _amount, _currentBlockNumber);
    }


    function registration() public {
        require(userInfo[msg.sender].lastBlock == 0, "User already exist");
        UserInfo storage _userInfo = userInfo[msg.sender];
        _userInfo.rewardDebt = 0;
        _userInfo.lastBlock = block.number;
        users.push(msg.sender);
    }


    function getData(uint256 _amount,
                    uint256 _lastBlockNumber,
                    uint256 _currentBlockNumber,
                    address _sender) public pure returns(bytes32) {
        return sha256(abi.encode(_amount, _lastBlockNumber, _currentBlockNumber, _sender));
    }


    /**
      * @dev
      *
      * @param _newModule - new module of key
      * @param _keyExponent - new exponent of key
      * Can only be called by the current owner.
      */
    function addNewKey(bytes memory _newModule, bytes memory _keyExponent) public onlyOwner returns(uint256) {
        keyInfo.push(KeyInfo({keyModule: _newModule, exponent: _keyExponent, keyStatus: true}));
        emit AddNewKey(_newModule, keyInfo.length - 1);
        return keyInfo.length - 1;
    }


    /**
      * @dev
      *
      * @param _keyId - available public key for signing.
      * Can only be called by the current owner.
      */
    function enableKey(uint256 _keyId) public onlyOwner {
        require(!keyInfo[_keyId].keyStatus, "This key already enable");
        keyInfo[_keyId].keyStatus = true;
    }


    /**
      * @dev
      *
      * @param _keyId - available public key for signing.
      * Can only be called by the current owner.
      */
    function disableKey(uint256 _keyId) public onlyOwner {
        require(keyInfo[_keyId].keyStatus, "This key already disable");
        keyInfo[_keyId].keyStatus = false;
    }


    /**
      * @dev Return info about available key
      * @param _keyId - available public key for signing
      */
    function getKeyInfo(uint256 _keyId) public view returns(bytes memory _key, bytes memory _exponent, bool _status) {
        _key = keyInfo[_keyId].keyModule;
        _exponent = keyInfo[_keyId].exponent;
        _status = keyInfo[_keyId].keyStatus;
    }


    /**
      * @dev - return Number of keys
      */
    function getKeyCount() public view returns(uint256) {
        return keyInfo.length;
    }


    /**
     * @dev - return Number of users
     */
    function getUsersCount() public view returns(uint256) {
        return users.length;
    }


    /**
     * @dev - return address of user
     * @param - _userId - unique number of user in array
     */
    function getUser(uint256 _userId) public view returns(address) {
        return users[_userId];
    }


    /**
     * @dev - return total rewards
     */
    function getTotalRewards(address _user) public view returns(uint256) {
        return userInfo[_user].rewardDebt;
    }


    /**
    * @param - _id - multiplier's id (0-4)
    * @dev - return value of multiplier
    */
    function getValueMultiplier(uint256 _id) public view returns(uint256) {
        return multipliers[_id];
    }


    /**
    * @param - _id - epoch's id(0-4)
    * @dev - return value of epoch
    */
    function getValueEpoch(uint256 _id) public view returns(uint256) {
        return epochs[_id];
    }


    function getMultiplier(uint256 f, uint256 t) public view returns(uint256) {
        return getInterval(min(t, epochs[1]), max(f, epochs[0])) * multipliers[0] +
        getInterval(min(t, epochs[2]), max(f, epochs[1])) * multipliers[1] +
        getInterval(min(t, epochs[3]), max(f, epochs[2])) * multipliers[2] +
        getInterval(min(t, epochs[4]), max(f, epochs[3])) * multipliers[3] +
        getInterval(max(t, epochs[4]), max(f, epochs[4])) * multipliers[4];
    }


    function getCurrentMultiplier() public view returns(uint256) {
        if (block.number < epochs[0]) {
            return 0;
        }
        if (block.number < epochs[1]) {
            return multipliers[0];
        }
        if (block.number < epochs[2]) {
            return multipliers[1];
        }
        if (block.number < epochs[3]) {
            return multipliers[2];
        }
        if (block.number < epochs[4]) {
            return multipliers[3];
        }
        if (block.number > epochs[4]) {
            return multipliers[4];
        }
    }

}

{
  "compilationTarget": {
    "ShadowStaking.sol": "ShadowStaking"
  },
  "evmVersion": "istanbul",
  "libraries": {},
  "metadata": {
    "bytecodeHash": "ipfs"
  },
  "optimizer": {
    "enabled": true,
    "runs": 200
  },
  "remappings": []
}