ZKay

pragma zkay ^0.3.0;

// Simple private token: each balance is encrypted under the owner's key
contract PrivateToken {
    mapping(address!x => uint@x) balances;

    constructor() public {
        balances[me] = 1000000;
    }

    function transfer(address to, uint@me val) public {
        balances[me] = balances[me] - val;
        balances[to] = balances[to] + reveal(val, to);
    }

    function deposit(uint val) public payable {
        balances[me] = balances[me] + val;
    }

    function withdraw(uint@me val) public {
        balances[me] = balances[me] - val;
    }
}