This is the third challenge on ethernaut: https://ethernaut.openzeppelin.com/level/0x4dF32584890A0026e56f7535d0f2C6486753624fInvestigationThis contract is for a simple coin flip. Something like this might be used in a game where people bet money on a coin flip, thus making it valuable to try to beat the system. The contract creates a random number using the block hash of the current block number. This block hash is divided by (UINT_256_MAX - 1) / 2. Thus, there is a 50% chance for true and 50...

This is the third challenge on ethernaut: https://ethernaut.openzeppelin.com/level/0x4dF32584890A0026e56f7535d0f2C6486753624fInvestigationThis contract is for a simple coin flip. Something like this might be used in a game where people bet money on a coin flip, thus making it valuable to try to beat the system. The contract creates a random number using the block hash of the current block number. This block hash is divided by (UINT_256_MAX - 1) / 2. Thus, there is a 50% chance for true and 50...

My solution to the 7th ethernaut challenge. This was so far the most difficult challenge for me https://ethernaut.openzeppelin.com/level/0x43BA674B4fbb8B157b7441C2187bCdD2cdF84FD5InvestigationWe are given a fun little ponzi scheme contract. The contract stores a prize in ether which can be gained by playing the game. To get the prize, simply send more ether to the contract and the new ether amount becomes the new prize. The contract will then set your address as the new king.// SPDX-License-I...

My solution to the 7th ethernaut challenge. This was so far the most difficult challenge for me https://ethernaut.openzeppelin.com/level/0x43BA674B4fbb8B157b7441C2187bCdD2cdF84FD5InvestigationWe are given a fun little ponzi scheme contract. The contract stores a prize in ether which can be gained by playing the game. To get the prize, simply send more ether to the contract and the new ether amount becomes the new prize. The contract will then set your address as the new king.// SPDX-License-I...

This is my solution to the fourth challenge of ethernaut: https://ethernaut.openzeppelin.com/level/0x0b6F6CE4BCfB70525A31454292017F640C10c768InvestigationThis problem is for a pretty simple contract// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; contract Telephone { address public owner; constructor() public { owner = msg.sender; } function changeOwner(address _owner) public { if (tx.origin != msg.sender) { owner = _owner; } } } It simply has an owner and a function to change the owne...

This is my solution to the fourth challenge of ethernaut: https://ethernaut.openzeppelin.com/level/0x0b6F6CE4BCfB70525A31454292017F640C10c768InvestigationThis problem is for a pretty simple contract// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; contract Telephone { address public owner; constructor() public { owner = msg.sender; } function changeOwner(address _owner) public { if (tx.origin != msg.sender) { owner = _owner; } } } It simply has an owner and a function to change the owne...

InvestigationStarted here by reading the description and the things that might help. Next, I started to go through the contract to understand what was going on. First, I saw the use of using which I wasn't sure what it meant.using SafeMath for uint256; I found that the using directive is taking functionality from the SafeMath library and applying them to uint256. This is Solidity's way of extending functionality of built in expressions. Next, upmapping(address => uint) public contri...

InvestigationStarted here by reading the description and the things that might help. Next, I started to go through the contract to understand what was going on. First, I saw the use of using which I wasn't sure what it meant.using SafeMath for uint256; I found that the using directive is taking functionality from the SafeMath library and applying them to uint256. This is Solidity's way of extending functionality of built in expressions. Next, upmapping(address => uint) public contri...

My solution for the fifth ethernaut challenge: https://ethernaut.openzeppelin.com/level/0x63bE8347A617476CA461649897238A31835a32CEInvestigationWe have a Token contract that contains balances for address and a total supply.mapping(address => uint) balances; uint public totalSupply; We have a constructor which initializes a contract instance with a provided supply and gives that entire balance to the contract deployerconstructor(uint _initialSupply) public { balances[msg.sender] = totalSupply =...

My solution for the fifth ethernaut challenge: https://ethernaut.openzeppelin.com/level/0x63bE8347A617476CA461649897238A31835a32CEInvestigationWe have a Token contract that contains balances for address and a total supply.mapping(address => uint) balances; uint public totalSupply; We have a constructor which initializes a contract instance with a provided supply and gives that entire balance to the contract deployerconstructor(uint _initialSupply) public { balances[msg.sender] = totalSupply =...

My solution for my 6th ethernaut challenge: https://ethernaut.openzeppelin.com/level/0x22699e6AdD7159C3C385bf4d7e1C647ddB3a99eaInvestigationThe code for the contract here is very simple. The contract does not have a receive or fallback function, so it does not intend to receive any ether. The challenge here is to send some ether to the contract unexpectedly.// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; contract Force {/* MEOW ? /\_/\ / ____/ o o \ /~____ =ø= / (______)__m_m) */} I w...

My solution for my 6th ethernaut challenge: https://ethernaut.openzeppelin.com/level/0x22699e6AdD7159C3C385bf4d7e1C647ddB3a99eaInvestigationThe code for the contract here is very simple. The contract does not have a receive or fallback function, so it does not intend to receive any ether. The challenge here is to send some ether to the contract unexpectedly.// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; contract Force {/* MEOW ? /\_/\ / ____/ o o \ /~____ =ø= / (______)__m_m) */} I w...

InvestigationThe problem is to claim ownership of the following contract// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; import '@openzeppelin/contracts/math/SafeMath.sol'; contract Fallout { using SafeMath for uint256; mapping (address => uint) allocations; address payable public owner; /* constructor */ function Fal1out() public payable { owner = msg.sender; allocations[owner] = msg.value; } modifier onlyOwner { require( msg.sender == owner, "caller is not the owner" ); _; } function...

InvestigationThe problem is to claim ownership of the following contract// SPDX-License-Identifier: MIT pragma solidity ^0.6.0; import '@openzeppelin/contracts/math/SafeMath.sol'; contract Fallout { using SafeMath for uint256; mapping (address => uint) allocations; address payable public owner; /* constructor */ function Fal1out() public payable { owner = msg.sender; allocations[owner] = msg.value; } modifier onlyOwner { require( msg.sender == owner, "caller is not the owner" ); _; } function...