openzeppelin-contracts/contracts/token/BurnableToken.sol

pragma solidity ^0.4.13;

import './StandardToken.sol';

/**
 * @title Burnable Token
 * @dev Token that can be irreversibly burned (destroyed).
 */
contract BurnableToken is StandardToken {

    /**
     * @dev Burns a specific amount of tokens.
     * @param _value The amount of token to be burned.
     */
    function burn(uint _value)
        public
    {
        require(_value > 0);

        address burner = msg.sender;
        balances[burner] = balances[burner].sub(_value);
        totalSupply = totalSupply.sub(_value);
        Burn(burner, _value);
    }

    event Burn(address indexed burner, uint indexed value);
}