I´m working in a smart contract where the tokens are distributed to 4 addresses. My intention is to set a timelock vesting to 3 addresses, so the tokens of those wallets will be released after 48 months. I´ve tried several methods to implement it, but I couldn´t make it work. Any help? This is the ropsten address of the contract https://ropsten.etherscan.io/address/0x1f80b573e5e4bf8b9025e4e6ebbcf3070b9d1074#code and this is the code:

pragma solidity ^0.4.24;


    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
    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/>.


library SafeMath {
    function mul(uint256 a, uint256 b) internal pure returns (uint256) {
        if (a == 0) {
            return 0;
        uint256 c = a * b;
        assert(c / a == b);
        return c;

    function div(uint256 a, uint256 b) internal pure returns (uint256) {
        // assert(b > 0); // Solidity automatically throws when dividing by 0
        uint256 c = a / b;
        // assert(a == b * c + a % b); // There is no case in which this doesn't hold
        return c;

    function sub(uint256 a, uint256 b) internal pure returns (uint256) {
        assert(b <= a);
        return a - b;

    function add(uint256 a, uint256 b) internal pure returns (uint256) {
        uint256 c = a + b;
        assert(c >= a);
        return c;

contract Ownable {

    address public owner;

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

    constructor() internal {
        owner = msg.sender;

    modifier onlyOwner() {
        require(msg.sender == owner);

    function transferOwnership(address newOwner) public onlyOwner {
        require(newOwner != address(0));
        emit OwnershipTransferred(owner, newOwner);
        owner = newOwner;

contract VALLE_ERC20 is Ownable {

    using SafeMath for uint256;

    mapping (address => uint256) public balances;

    mapping (address => mapping (address => uint256)) internal allowed;

    // Public variables for the VALLE ERC20 VLL token contract
    string public constant standard = "VALLE erc20 and Genesis";
    uint256 public constant decimals = 18;   // hardcoded to be a constant
    string public name = "VALLE";
    string public symbol = "VLL";
    uint256 public totalSupply;

    event Transfer(address indexed from, address indexed to, uint256 value);
    event Approval(address indexed owner, address indexed spender, uint256 value);

    function balanceOf(address _owner) public view returns (uint256) {
        return balances[_owner];

    function transfer(address _to, uint256 _value) public returns (bool) {

        require(_to != address(0));
        require(_value <= balances[msg.sender]);
        // SafeMath.sub will throw if there is not enough balance.
        balances[msg.sender] = balances[msg.sender].sub(_value);

        balances[_to] = balances[_to].add(_value);

        emit Transfer(msg.sender, _to, _value);
        return true;

    function transferFrom(address _from, address _to, uint256 _value) public returns (bool) {
        require(_to != address(0));
        require(_value <= balances[_from]);
        require(_value <= allowed[_from][msg.sender]);

        balances[_from] = balances[_from].sub(_value);
        allowed[_from][msg.sender] = allowed[_from][msg.sender].sub(_value);

        balances[_to] = balances[_to].add(_value);

        emit Transfer(_from, _to, _value);
        return true;

    function approve(address _spender, uint256 _value) public returns (bool) {
        allowed[msg.sender][_spender] = _value;
        emit Approval(msg.sender, _spender, _value);
        return true;

    function allowance(address _owner, address _spender) public view returns (uint256) {
        return allowed[_owner][_spender];

    function increaseApproval(address _spender, uint _addedValue) public returns (bool) {
        allowed[msg.sender][_spender] = allowed[msg.sender][_spender].add(_addedValue);
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;

    function decreaseApproval(address _spender, uint _subtractedValue) public returns (bool) {
        uint oldValue = allowed[msg.sender][_spender];
        if (_subtractedValue > oldValue) {
            allowed[msg.sender][_spender] = 0;
        } else {
            allowed[msg.sender][_spender] = oldValue.sub(_subtractedValue);
        emit Approval(msg.sender, _spender, allowed[msg.sender][_spender]);
        return true;

    /* Approve and then communicate the approved contract in a single tx */
    function approveAndCall(address _spender, uint256 _value, bytes _extraData) public returns (bool success) {
        tokenRecipient spender = tokenRecipient(_spender);

        if (approve(_spender, _value)) {
            spender.receiveApproval(msg.sender, _value, this, _extraData);
            return true;

interface tokenRecipient {
    function receiveApproval(address _from, uint256 _value, address _token, bytes _extraData) external ;

// This creates and adds two genesis pools of VLL tokens to the balance of the A,B,C and D ETH addresses

contract VALLE is VALLE_ERC20 {

        address public A;
        address public B;
        address public C;
        address public D;

    constructor (

        ) public {

        A = 0x90Cbbe589765c0992cf2A2316BAB532A95C80a2a;
        B = 0x145405fC576fee86f2AdFBBDb3F1238F8B59F2d0;
        C = 0xC349954E5e620aCBB060b52B24a90A59d3eb10e8;
        D = 0x55D5C6475AAFF21e950Aa072D102Be524B4e6f5F;





You have 2 ways of dealing with time locked tokens.

1) implement the lock inside the token contract

  • add a mapping where you store addresses that are time locked
  • in the transfer() and transferFrom() methods, add a check for time has passed if the msg.sender is present in said mapping.

2) implement the lock in 3 new smart contracts that act as vaults. ( this could be a solution if your token contract is already live )

  • implement an "exit" method that calls the erc20 contract
  • only allow execution if "now" is later than the time you want them to be unlocked.

Method 2 would be preferred since it would not increase gas costs for every transfer call just because of the 3 locked wallets.

  • Do you know the address of any contract that has already implemented your option 2?
    – Gerardo
    Jul 29 '18 at 0:12

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