DAK Securities Coin Smart Contract (ERC20 Token Specification)
Summary
This document is a specimen smart contract for DAK Coin, an ERC20-compliant cryptocurrency token. The contract defines the creation and management of DAK Coin, including its total supply, transfer rules, and approval mechanisms. All tokens are initially assigned to the creator, who can then distribute them. The contract includes standard ERC20 functions for transferring tokens, checking balances, and managing allowances. It also incorporates safety checks for arithmetic operations. The parties involved are the token creator and future holders of DAK Coin.
EX-4.3 6 dako_ex43.htm CONTRACT dako_ex43.htm
EXHIBIT 4.3
Specimen DAK Securities Coin Smart Contract
pragma solidity ^0.4.18;
contract SafeMath {
function safeAdd(uint256 x, uint256 y) internal returns(uint256) {
uint256 z = x + y;
assert((z >= x) && (z >= y));
return z;
}
function safeSubtract(uint256 x, uint256 y) internal returns(uint256) {
assert(x >= y);
uint256 z = x - y;
return z;
}
function safeMult(uint256 x, uint256 y) internal returns(uint256) {
uint256 z = x * y;
assert((x == 0)||(z/x == y));
return z;
}
}
contract Token {
uint256 public totalSupply;
function balanceOf(address _owner) constant returns (uint256 balance);
function transfer(address _to, uint256 _value) returns (bool success);
function transferFrom(address _from, address _to, uint256 _value) returns (bool success);
function approve(address _spender, uint256 _value) returns (bool success);
function allowance(address _owner, address _spender) constant returns (uint256 remaining);
event Transfer(address indexed _from, address indexed _to, uint256 _value);
event Approval(address indexed _owner, address indexed _spender, uint256 _value);
}
/* ERC 20 token */
contract StandardToken is Token, SafeMath {
mapping (address => uint256) balances;
mapping (address => mapping (address => uint256)) allowed;
modifier onlyPayloadSize(uint numwords) {
assert(msg.data.length == numwords * 32 + 4);
_;
}
function transfer(address _to, uint256 _value)
returns (bool success)
{
if (balances[msg.sender] >= _value && _value > 0 && balances[_to] + _value > balances[_to]) {
balances[msg.sender] = safeSubtract(balances[msg.sender], _value);
balances[_to] = safeAdd(balances[_to], _value);
Transfer(msg.sender, _to, _value);
return true;
} else {
return false;
}
}
function transferFrom(address _from, address _to, uint256 _value)
returns (bool success)
{
if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0 && balances[_to] + _value > balances[_to]) {
balances[_to] = safeAdd(balances[_to], _value);
balances[_from] = safeSubtract(balances[_from], _value);
allowed[_from][msg.sender] = safeSubtract(allowed[_from][msg.sender], _value);
Transfer(_from, _to, _value);
return true;
} else {
return false;
}
}
function balanceOf(address _owner) constant returns (uint256 balance) {
return balances[_owner];
}
function approve(address _spender, uint256 _value)
onlyPayloadSize(2)
returns (bool success)
{
allowed[msg.sender][_spender] = _value;
Approval(msg.sender, _spender, _value);
return true;
}
function allowance(address _owner, address _spender)
constant
onlyPayloadSize(2)
returns (uint256 remaining)
{
return allowed[_owner][_spender];
}
}
/**
* @title DAKCoin
* @dev ERC20 Token, where all tokens are pre-assigned to the creator.
* Note they can later distribute these tokens as they wish using `transfer` and other
* `StandardToken` functions.
*/
contract DAKCoin is StandardToken {
string public name = "DAK Coin";
string public symbol = "DAKS";
uint256 public decimals = 18;
uint256 public INITIAL_SUPPLY = 1750000000 * 1 ether;
/**
* @dev Contructor that gives msg.sender all of existing tokens.
*/
function DakCoin() {
totalSupply = INITIAL_SUPPLY;
balances[msg.sender] = INITIAL_SUPPLY;
}
}
