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

The Bitcoin Puzzle Challenge, a decade-old onchain bounty system now holding roughly 916.52 BTC worth approximately $58.87 million at current prices, sits at a new frontier as community solvers push past Puzzle 70 and set their sights on a 71-bit keyspace target that pool telemetry suggests could take centuries to brute-force.

The structure changed materially in 2017 when funds from addresses 161 through 256 were moved into the lower-range addresses, consolidating the challenge to 160 active puzzles. In 2019, the creator sent small outgoing transactions from every fifth address in a sequence that included 65, 70, 75, 80, and up through 160. Those partial spends revealed public keys onchain for those outputs, a detail that later proved significant for how solvers could approach those specific puzzles.

The creator behind the challenge remains anonymous in any provable sense. The handle most commonly cited in forum history is saatoshi_rising, which later Bitcointalk posts attribute to an “I am the creator” claim. Comments attributed to that account describe the puzzle keys as consecutive outputs from a deterministic wallet with leading bits masked to set difficulty, and frame the whole exercise as a measuring instrument for community cracking strength rather than a puzzle with a hidden algebraic trick. That attribution is influential but unverified.

That one-bit increase over the prior puzzle doubles the raw search work. Each step upward in the puzzle sequence works exactly that way.

A June 23, 2026, snapshot from btcpuzzle.info put the scale in concrete terms: the community pool had scanned 290,012 of 33,554,432 assigned ranges, was operating at 57.3 billion keys per second, had covered 0.864 percent of the total puzzle space, and was on pace to complete the search in roughly 421.92 years at the average speed recorded at that moment.

The unsolved puzzle set splits into two distinct categories, and the approach differs depending on which type a solver targets.

Puzzles 135, 140, 145, 150, 155, and 160 currently have known public keys. When a public key is available, solvers can apply Pollard’s Kangaroo method, an interval discrete logarithm approach with square-root-type complexity in the size of the interval. The JeanLucPons Kangaroo project, built specifically for the secp256k1 curve with multi-GPU support, is the most widely cited public implementation of this method.

That distinction is not academic. Known-public-key puzzles offer a material algorithmic advantage over address-only targets of similar bit depth, even though they are still enormous undertakings.

Three codebases dominate community discussion. Bitcrack, maintained on Github by brichard19, is the established reference for GPU-based address scanning on the lower-difficulty address-only puzzles. Keyhunt by albertobsd supports multiple attack modes, including raw address matching and discrete-log workflows, making it the most versatile public option across both target classes. JeanLucPons’ Kangaroo handles the known-public-key interval attacks.

Pool infrastructure such as btcpuzzle.info distributes the work across contributors by slicing the interval into hex subranges and assigning them to participating workers. That coordination layer is range accounting and telemetry, not a new cryptographic method.

Recent solve history for puzzles 67 and 68 involved transactions that did not travel through the ordinary public mempool path. The practical implication is clear: successfully claiming a reward requires managing the final transaction with the same care as the key search itself.