--- title: "hexbyte (@hexbyte) | Hashnode" description: "hexbyte (@hexbyte) writes on Hashnode. Read their latest articles and follow their work." url: "https://hashnode.com/@hexbyte" --- @hexbyte # hexbyte @hexbyte · Joined April 2023 ### [Ethernaut Series - 05 (Token)](https://blog.hexbyte.in/ethernaut-ctf-series-05-token?utm_source=hashnode&utm_medium=feed) Concept The emphasis of this level is on the concept of overflow and underflow which is a concern for contracts written in solidity version <0.8. Basically, there are different types of integer data type. For example, uint256, int256, uint8, int8. Ea... 2 min read · [blog.hexbyte.in](https://blog.hexbyte.in/ethernaut-ctf-series-05-token?utm_source=hashnode&utm_medium=feed) [Oct 13, 2024](https://hashnode.com/posts/ethernaut-ctf-series-05-token/670c1d8e1f5d63f2857c0297) ### [Ethernaut Series - 04 (Telephone)](https://blog.hexbyte.in/ethernaut-ctf-series-04-telephone?utm_source=hashnode&utm_medium=feed) Concept The main concept being taught in this level is the difference between the use of tx.origin and msg.sender. Let’s try and understand this using the following image: Observations: If Bob calls contract A, the contract will see the value of tx... 2 min read · [blog.hexbyte.in](https://blog.hexbyte.in/ethernaut-ctf-series-04-telephone?utm_source=hashnode&utm_medium=feed) [Oct 13, 2024](https://hashnode.com/posts/ethernaut-ctf-series-04-telephone/670c0aa266774d128067bca4) ### [Ethernaut Series - 03 (Coin Flip)](https://blog.hexbyte.in/ethernaut-ctf-series-03-coin-flip?utm_source=hashnode&utm_medium=feed) Overview This level presents us with a coin flipping game. We need to maintain a winning streak of 10 by guessing the outcome of a coin flip. The concept being taught here is the one about randomness. There is no inherit source of randomness in Ether... 3 min read · [blog.hexbyte.in](https://blog.hexbyte.in/ethernaut-ctf-series-03-coin-flip?utm_source=hashnode&utm_medium=feed) [Oct 7, 2024](https://hashnode.com/posts/ethernaut-ctf-series-03-coin-flip/6703bdb3a7bf6a121636f2bd) ### [Ethernaut Series - 02 (Fal1out)](https://blog.hexbyte.in/ethernaut-ctf-series-02?utm_source=hashnode&utm_medium=feed) We are asked to claim ownership of a contract whose code is provided as such: // SPDX-License-Identifier: MIT pragma solidity ^0.6.0; import "openzeppelin-contracts-06/math/SafeMath.sol"; contract Fallout { using SafeMath for uint256; mapp... 4 min read · [blog.hexbyte.in](https://blog.hexbyte.in/ethernaut-ctf-series-02?utm_source=hashnode&utm_medium=feed) [Oct 5, 2024](https://hashnode.com/posts/ethernaut-ctf-series-02/6701a470147bbaf3deeebce7) ### [Ethernaut Series - 01](https://blog.hexbyte.in/ethernaut-ctf-series-01-1?utm_source=hashnode&utm_medium=feed) The challenge asks us to claim the ownership of the contract and reduce its balance to 0. In this case, we have been provided with the contract itself. // SPDX-License-Identifier: MIT pragma solidity ^0.8.0; contract Fallback { mapping(address =... 3 min read · [blog.hexbyte.in](https://blog.hexbyte.in/ethernaut-ctf-series-01-1?utm_source=hashnode&utm_medium=feed) [Oct 5, 2024](https://hashnode.com/posts/ethernaut-ctf-series-01-1/67019a0ae97bddaeda50cd43)