FAQ
Short questions, labeled answers
Short answers on the 2015 catalog: the object, the two search classes, expected value, and labeled stories. Figures that are not on-chain are marked.
The object
What the 2015 series is, and what the numbers on this site mean.
What is the Bitcoin Puzzle?
A set of Bitcoin addresses funded from January 2015. Address N is restricted to private keys in 2N−1 ... 2N - 1. In April 2017, BitcoinTalk user saatoshi_rising claimed authorship. That is a forum statement, not a cryptographic proof.
How much BTC is still unclaimed?
Open records carry a nominal catalog allocation. That sum is not a live wallet and is read from the catalog snapshot, not frozen here on this page. Verify each address on an explorer. Catalog unit is not UTXO.
Why are some puzzles harder than others?
Each increment doubles the candidate interval. #71 has 270 keys. #160 has 2159. That doubling is why #72 and #160 are not the same world.
Search classes
Which target, which algorithm. No product names.
Which one should I try?
Address-only: #71 is the lowest target; search is HASH160 brute force. Known public key: #140 is the primary bounded kangaroo, also #145, #150, #155, #160 in the 14 Sep 2026 catalog re-check. Higher address-only ranges are not practical with current brute force.
What does known public key mean?
A P2PKH spend reveals the public key in the scriptSig. On 16 May 2019, 1,000-sat outputs were deposited on puzzle #1 plus the every-fifth series #65–#160; a receive leaks nothing. On 1 June 2019 those 20 series outputs were spent together with extra input 1PvaqLqRAivje7CactLR55xQBYvBeaDrXN, and that spend exposed the series compressed public keys, enabling kangaroo/BSGS on a bounded interval. #135 was spent on 2026-07-28. Remaining kangaroo-class in this snapshot: #140, #145, #150, #155, #160. A spend is not the only way a key becomes known.
Do ASICs help?
No. Mining ASICs compute SHA-256d. Puzzle search is secp256k1 scalar work: HASH160 of encodings, or group operations when a public key is known. GPU software exists in public; this atlas does not ship or gate it.
Is it profitable?
Expected value is usually negative. For #140 with a 96-bit window, containment is 2−43, about 1 in 8.80 trillion (short scale). Hitting a kangaroo budget does not prove every key in the window was enumerated. If you want income, the math says no.
People and stories
Handles and rumors, labeled. Detail lives on cases, people, and theories.
What is known about puzzle 66?
#66 was spent on 12 September 2024. A confirmed destination is on-chain. Same-day confirmed spends of different UTXOs are not a double-spend of one outpoint. Claims about the finder, automated bots, and intent are community interpretation. The claim page explains why a public P2PKH broadcast exposes the public key.
Who is saatoshi_rising?
Unknown. The BitcoinTalk account posted the authorship claim on 27 April 2017. Forum statement. See History and Theories, including the Satoshi story and why one found key does not unlock the rest.
Can a quantum computer solve them?
Not with hardware that exists today. A spend on a high target with a known public key does not, by itself, identify the method. Treating those addresses as a quantum canary is speculation.
What are the usual wrong ideas?
ASICs do not search secp256k1. Kangaroo needs a public key, so not #71. Entering a live key into a website is how coins leave. A pool share is not the UTXO. GitHub solves-in-minutes demos replay the first spent keys. The myths page lists these so they stop travelling as tips.
Is this a pool or an exchange?
No. This site is the atlas: catalog, history, math. btcpuzzle.info is a solo pool. Nothing here is listed or sold. Longer boundary copy lives once on About.