Solvers Target $58.9M Bitcoin Puzzle; Puzzle 71 Needs 422 Years

Solvers are racing to claim rewards in the Bitcoin Puzzle Challenge, where 916.52 BTC is locked across 78 unsolved addresses, worth about $58.87 million at current prices. Community trackers show 82 puzzles solved and 78 still open as of June 23, 2026.

The immediate target is Puzzle 71, the lowest-numbered address-only prize still unsolved. Puzzle 71 holds roughly 7.1 BTC and requires searching the private-key interval from 2^70 to 2^71, which doubles the raw work compared with the prior one-bit step.

A June 23 snapshot of pool telemetry reported that contributors had scanned 290,012 of 33,554,432 assigned hex subranges, were running at about 57.3 billion key checks per second, and had covered roughly 0.864% of the total assigned ranges. At that average speed, the projected time to finish the full address-only search for Puzzle 71 was about 421.92 years.

The puzzle set began onchain with a Jan. 15, 2015 transaction that created 256 outputs and distributed 32.896 BTC in prizes. Public discussion started later that year. In 2017 the structure changed, consolidating funds into 160 active puzzles. In 2019 the creator made small outgoing transactions from every fifth address in a sequence, revealing public keys for those outputs.

In April 2023 the creator increased the advertised prizes by about tenfold, raising the modern value of unsolved rewards. Trackers now report the aggregate of unsolved and solved prizes at larger totals, while the active unsolved pool stands at 916.52 BTC.

The remaining puzzles fall into two technical categories that require different methods. Address-only targets such as Puzzle 71 require brute-force key testing: generate candidate private keys inside the allowed interval, derive the corresponding addresses, and check for a match. When a public key is already visible onchain, solvers can treat the problem as an interval discrete-log search.

For puzzles with known public keys, solvers often apply Pollard’s Kangaroo algorithm. That method reduces the algorithmic cost to roughly the square root of the interval size, which is much less work than a full address-only brute force for equivalent bit depth. Known-public-key puzzles currently include numbers such as 135, 140, 145, 150, 155 and 160.

Community tools reflect both approaches. Bitcrack is the common GPU-accelerated scanner used for address-only searches. Keyhunt supports address matching and discrete-log modes. A JeanLucPons Kangaroo implementation is widely used for multi-GPU discrete-log searches on the secp256k1 curve. Pool infrastructure such as btcpuzzle.info slices intervals into smaller ranges, assigns work to contributors and tracks coverage and speed.

Operational risks affect the final claim process. If a private key is exposed in the public mempool before a spend is confirmed, observers can extract the public key and convert an address-only search into a known-public-key interval attack, allowing faster follow-on exploitation. Recent solves showed transactions routed outside the ordinary mempool path to limit that exposure. Community participants note that completing a successful spend requires careful transaction handling and speed.

The creator remains anonymous. Forum posts under the handle saatoshi_rising describe the keys as consecutive outputs from a deterministic wallet with leading bits masked to set difficulty; that attribution has not been independently verified.