Smart Contract

https://medium.com/joyso/solidity-%E5%A3%93%E7%B8%AE%E6%99%BA%E8%83%BD%E5%90%88%E7%B4%84%E7%9A%84%E8%BC%B8%E5%85%A5%E8%B3%87%E6%96%99-65a870d1f04e

https://hackernoon.com/your-private-solidity-variable-is-not-private-save-it-before-it-becomes-public-52a723f29f5e 上面範例中，play(100)被呼叫後，從transcation data內得知 0x6587f6ec0000000000000000000000000000000000000000000000000000000000000064 然後先取得play()這部份的data bytes4(keccak256(‘play(uint)’)) 然後得知 0000000000000000000000000000000000000000000000000000000000000064 就是 uint部份，得到的這個值是經過hex才顯示的 byte32：00 為1個byte(16 bits)，共32個 64=> 6 * (16^1) + 4 * (16^0) = 100 uint256 => 2^256 => 8^32 => byte32