Krackpot Taps Browser GPUs to Hunt for 6-Bitcoin Puzzle Key

The Bitcoin Puzzle, created by an anonymous organizer in 2015, places private keys within progressively larger numerical ranges and rewards anyone who discovers them through brute-force searching. Puzzle 71 remains unsolved and carries a prize of 6 bitcoin. The challenge is less a practical vulnerability than a public demonstration of how quickly the search space expands, underscoring the security provided by Bitcoin’s elliptic-curve cryptography when keys are generated across sufficiently large ranges.

A developer has released Krackpot, a browser-based tool that uses WebGPU to tap a user’s graphics card and search for Puzzle 71’s private key. Anyone finding the key could claim the 6 bitcoin held at the puzzle address. The odds remain vanishingly small: estimates suggest a single GPU could require hundreds of thousands of years to complete the search, making the project primarily an experiment in distributed computing and browser-accessible GPU workloads rather than a realistic path to a payout.