The puzzle has been solved!

Congratulations to Arpox, who was the first person to solve the final stage and claim the 0.125 BTC! They’ve posted an amazing write-up on Medium, so check it out if you want to see how they solved the puzzle.

Here are the Bitcoin transactions for all four stages:

I’ve published all of the source code on GitHub, and I’ve written a series of blog posts with the solutions:

Welcome to the 2018 Bitcoin Programming Challenge!

This puzzle has four stages. You must solve each stage before you can proceed to the next stage. Completing a stage will give you the private key for a Bitcoin address. The first three stages have a prize of 0.005 BTC, and the final stage has a prize of 0.125 BTC: 1J8dc1baKVcg1gDocZSqf87pjUsKCx6AUw

If you’re the first person to complete a stage, you can claim the Bitcoins and transfer them to your own address. Good luck!

Before you begin, make sure you install a Bitcoin wallet program. You also need to know how to convert a 256-bit private key into the WIF format. Install the bitcoin-explorer command-line tool, or you can use this Ruby script.

1) PixelPerfect

The first stage is a CSS game called PixelPerfect, with 8 CSS puzzles. You are given some HTML, and you have to write some CSS that produces the target image.

If you want to skip the CSS game and start with a programming challenge, then you can start at stage 2:

2) Cubes

You are given a set of 3-dimensional blocks with different shapes. You must find the correct orientation and position for each block so that they form an 8x8x8 cube.