Developer Simon Males has launched Krackpot, a browser-based Bitcoin puzzle game that promises 6 BTC to anyone whose graphics card locates the private key controlling one of Bitcoin's longest-running public cryptographic challenges.

Krackpot targets Bitcoin Puzzle #71, an intentionally weakened wallet created as part of a 2015 challenge designed to demonstrate the difficulty of searching increasingly large private-key ranges. The series was set up by an anonymous party who funded addresses with private keys of increasing bit length, from 1 bit up to 160 bits, and the shorter-key entries have been solved steadily over the past decade as search software and GPU capacity improved. The address remains unsolved with approximately 7.1018 BTC held, and the game brands itself the “world's worst lottery” because of the extraordinary odds of finding the correct key.

Browser-Based Search Uses Local GPU Power

Krackpot runs through WebGPU directly inside a compatible desktop browser, with no dedicated application to install and no account to create. WebGPU is the browser interface for modern graphics and general-purpose GPU compute that began rolling out in major desktop browsers starting in 2023, which is what makes an install-free local search feasible. Participants supply a Bitcoin payout address and allow their GPU to search the puzzle's restricted keyspace locally.

Puzzle #71 limits the unknown private key to a range containing 2^70 possibilities, or roughly 1.18 sextillion candidates. That deliberately restricted range is fundamentally different from attempting to brute-force an ordinary Bitcoin private key drawn from the full secp256k1 keyspace, and Males built the project partly as a demonstration of that difference.

His technical breakdown of the WebGPU implementation estimates that a single gaming GPU would require roughly 830,000 years before expecting a successful hit. Even one million comparable GPUs searching continuously would bring the estimate down only to around one year.

Bitcoin's resistance to future cryptographic attacks has received increased attention this year as researchers examine risks beyond conventional brute force. Strategy recently launched a $15 million Bitcoin security consortium that includes post-quantum cryptography among its early research priorities.

Winner Receives 6 BTC From Puzzle Wallet

If Krackpot finds the target key, the application is designed to construct a signed transaction locally and route it through a private submission channel rather than exposing the recovered key through a normal public broadcast.

Exactly 6 BTC would be sent to the participant's chosen address, with the remaining balance directed to an address controlled by the developer. The project does not charge an entry fee and does not require participants to pool their computing resources. That marks a departure from how earlier, shorter-key entries in the series were often attacked, with coordinated teams running dedicated command-line search tools such as BitCrack.

The unusual challenge also arrives as real-world wallet weaknesses continue to demonstrate the difference between deliberately reduced cryptographic puzzles and accidental key-generation failures. Coinspect recently identified the Ill Bloom wallet flaw after roughly $5 million was drained, with weak randomness leaving thousands of addresses vulnerable.

Puzzle #71 Remains Unsolved

Bitcoin Puzzle #71 currently holds 7.10182686 BTC at address 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU, and the challenge is still listed as unsolved. The series continues up to 160-bit puzzles, each exponentially larger than the one before it, so the frontier of practically searchable keys has moved upward only gradually even as hardware improves.

Krackpot does not indicate that ordinary Bitcoin wallets can be cracked with consumer graphics cards. Its target exists specifically inside a dramatically reduced private-key range published for the puzzle, while properly generated Bitcoin keys remain outside the practical reach of conventional brute-force computing.

For Krackpot participants, the calculation remains deliberately unforgiving: approximately 2^70 possible keys, 6 BTC for the winner, and an estimated 830,000 years of searching for a single gaming GPU.

Source: Crypto Adventure