This challenge is quite interesting and particular as it’s the first one in which we need to dive into Ethereum’s storage layout. Let’s start by taking a look at the contract: The variables and functions are… A bool isComplete, which by default is set to false. An array map with…

The solution for this challenge is very straight forward: wait until the deployer is desperate enough to withdraw their funds before 10 years have passed, leaving 10% of them to us, or wait those 10 years and hope they remember about all of this. Great! In the next article we’ll…

With this new challenge, we need to step up our game a bit. Our first glance at the contract tells us that it’s more complex than the previous ones, just by the length and number of functions: Our objective here is to accumulate at least 1,000,000 SET tokens. Let’s start…

With the beginning of a new chapter of vulnerabilities, comes a new set of backdoors and hacking opportunities 🥳. The Capture The Ether’s Math section give us the chance to play with numbers and do a little bit of math. Let’s start by analyzing the first challenge: At first glance…

Let’s start by technically and conceptually understanding what we are trying to achieve in this challenge. It asks us to guess a hash allocated in a bytes32 variable, as per the keccak256’s format. But what’s that bytes32? I’ll try to explain as simple as possible what it is and why…

Is it possible to predict the future in the Ethereum world? The answer is: kind of. I’m not going to lie, I found this challenge quite difficult and it took me several days of trying and reading documentation before I could solve it. There are not straight forward ways to…

In this challenge we need to guess a new number with some similar characteristics to the previous one: the answer is the keccak256hash of the blockhash of the previous block and a timestamp, all casted to a uint8. In that last challenge the answer was created when deploying the contract…

Send ether to earn more ether (if the answer is right) — Creating a random number on-chain is a complex task. In fact, there are some workarounds to do it but in general, it’s highly recommended to do it off-chain, as almost every input that may be used for entropy is public and/or can be manipulated to some degree. Fortunately for us…

The objective of this challenge is to guess a ‘secret’ number. But is it? Let’s start from the beginning of the contract. The first line inside of it is our answerHash, a bytes32 variable with a ‘hash’. And what is that, exactly? Hash functions are functions that can be used…