Key Hunters Eye $58.87M Bitcoin Puzzle as 916 BTC Sits Unsolved in 78 Addresses

A Challenge Built Over a Decade

The puzzle did not statesman arsenic the monolithic bounty strategy it is today. Its earliest verified onchain root is simply a Jan. 15, 2015, transaction that funded 256 outputs with rewards scaling from 0.001 BTC to 0.256 BTC, totaling 32.896 BTC. A Bitcointalk thread opened Dec. 28, 2015, nether the rubric “ Bitcoin puzzle transaction ~32 BTC prize to who solves it” marked the archetypal large nationalist treatment of the challenge.

A simulated travel illustration utilizing mempool.space visuals of the archetypal Bitcoin Puzzle Challenge transportation that occurred connected Jan. 15, 2015. The full batch outgo was confirmed astatine artifact tallness 339085.

The operation changed materially successful 2017 erstwhile funds from addresses 161 done 256 were moved into the lower-range addresses, consolidating the situation to 160 progressive puzzles. In 2019, the creator sent tiny outgoing transactions from each 5th code successful a series that included 65, 70, 75, 80, and up done 160. Those partial spends revealed nationalist keys onchain for those outputs, a item that aboriginal proved important for however solvers could attack those circumstantial puzzles.

The bounty reached its modern standard successful April 2023, erstwhile prizes crossed unsolved puzzles were accrued by astir 10 times. Puzzle 66 roseate to 6.6 BTC. Puzzle 160 reached 16 BTC. Current trackers study an aggregate reward of astir 989.04 BTC.

Where the Frontier Stands Now

As of mid-June 2026, assemblage trackers amusement 82 of the 160 puzzles solved and 78 remaining. With bitcoin trading astir $64,232, the unsolved excavation carries a spot worth adjacent $58.87 million.

Statistics from btcpuzzle.info connected June 23, 2026.

The creator down the situation remains anonymous successful immoderate provable sense. The grip astir commonly cited successful forum past is saatoshi_rising, which aboriginal Bitcointalk posts property to an “I americium the creator” claim. Comments attributed to that relationship picture the puzzle keys arsenic consecutive outputs from a deterministic wallet with starring bits masked to acceptable difficulty, and framework the full workout arsenic a measuring instrumentality for assemblage cracking spot alternatively than a puzzle with a hidden algebraic trick. That attribution is influential but unverified.

Puzzle 71: The Next Target

Solvers who way outdated guides whitethorn inactive spot Puzzle 66 listed arsenic the easiest remaining target. It is not. Trackers present people puzzles 69 and 70 arsenic solved. The existent lowest-numbered unsolved address-only people is Puzzle 71, which carries astir 7.1 BTC and requires searching a keyspace successful the scope from 2^70 to 2^71.

Statistics from btcpuzzle.info connected June 23, 2026.

That one-bit summation implicit the anterior puzzle doubles the earthy hunt work. Each measurement upward successful the puzzle series works precisely that way.

A June 23, 2026, snapshot from btcpuzzle.info enactment the standard successful factual terms: the assemblage excavation had scanned 290,012 of 33,554,432 assigned ranges, was operating astatine 57.3 cardinal keys per second, had covered 0.864 percent of the full puzzle space, and was connected gait to implicit the hunt successful astir 421.92 years astatine the mean velocity recorded astatine that moment.

Two Classes of Targets

The unsolved puzzle acceptable splits into 2 chiseled categories, and the attack differs depending connected which benignant a solver targets.

For address-only puzzles specified arsenic Puzzle 71 and its neighbors 72, 73, and 74, the method is brute force: trial campaigner private keys wrong the allowed interval, deduce the corresponding address, and look for a match. For puzzles wherever a nationalist cardinal is already known onchain, a antithetic people of algorithm applies.

Puzzles 135, 140, 145, 150, 155, and 160 presently person known nationalist keys. When a nationalist cardinal is available, solvers tin use Pollard’s Kangaroo method, an interval discrete logarithm attack with square-root-type complexity successful the size of the interval. The JeanLucPons Kangaroo project, built specifically for the secp256k1 curve with multi-GPU support, is the astir wide cited nationalist implementation of this method.

That favoritism is not academic. Known-public-key puzzles connection a worldly algorithmic vantage implicit address-only targets of akin spot depth, adjacent though they are inactive tremendous undertakings.

The Software Stack

Three codebases predominate assemblage discussion. Bitcrack, maintained connected Github by brichard19, is the established notation for GPU-based code scanning connected the lower-difficulty address-only puzzles. Keyhunt by albertobsd supports aggregate onslaught modes, including earthy code matching and discrete-log workflows, making it the astir versatile nationalist enactment crossed some people classes. JeanLucPons’ Kangaroo handles the known-public-key interval attacks.

Bitcrack is simply a GPU-accelerated command-line instrumentality designed to brute-force Bitcoin private keys utilizing CUDA and OpenCL. Its superior nonsubjective is to assistance successful solving the Bitcoin puzzle transactions by scanning ample ranges of keyspaces for specified people addresses.

Pool infrastructure specified arsenic btcpuzzle.info distributes the enactment crossed contributors by slicing the interval into hex subranges and assigning them to participating workers. That coordination furniture is scope accounting and telemetry, not a caller cryptographic method.

Finding the Key Is Not the Whole Game

Community past astir puzzles 66 done 69 documents a hazard that solvers who absorption lone connected the cryptographic situation thin to overlook. When a private key is exposed to the nationalist mempool earlier a walk is confirmed, observers tin extract the nationalist cardinal from the pending transaction. That converts a axenic address-hunting occupation into a known-public-key interval problem, which faster algorithms tin past attack.

Recent lick past for puzzles 67 and 68 progressive transactions that did not question done the mean nationalist mempool path. The applicable accusation is clear: successfully claiming a reward requires managing the last transaction with the aforesaid attraction arsenic the cardinal hunt itself.