quizchain/31

Solved on 2019-04-13 after 3h 42m, key derived from the published recipe. 0.007 BTC on Bitcoin.

Story

What the post asked, what the answer turned out to be, and what the chain says happened. The record below holds the data.

A before B

"BItcoin Second." The field is called BFUB now, brute force user block. The FU in the middle is purely technical, of course.

The first letter of Bitcoin is B, and the letter before it is A. So A BFUB Before B fTS. Almost four hours for a one letter answer. Compare that with blocks 25 and 26, which went in minutes, and you see what the field was for.

IDquizchain/3131 / 772019-04-13

Puzzle / quizchain

31

bitcoinp2pkh solved

Record

bitcoinPuzzle({
  address: p2pkh("1UQPCtfgohV2…yUsT7AQf", "052ebffefa52…68a838f0"),
  status: Status.Solved,
  key: wif("L51KtCtDoT28…eGpaH3NJ").entropy("26c9d319d442…a0843af5", source("https://www.…lock_31/")).derived(),
})

Prize: 0.007 BTC
Key material: wif, derived from the recipe
Verification: verified
Solved: 2019-04-13 · 3h 42m

tx 2

Trail: Explorerblockstream.info; Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31; Tryquizchain/31 in the playground

Address: 1UQPCtfgohV2trpRfcgcNgTxEyUsT7AQf

hash160 052ebffefa521b22df7a3b42ca63cb5668a838f0

Balance

asking the explorer

Key

public key · compressed: 02511924b3c1ba1e38dcc211d55cde81582e6df5a3a2cfe7824fbfc43a822c055f
WIF: L51KtCtDoT28gTj335pW6Z7zbDY5m2RbsZiCQhNfbMRNeGpaH3NJ
entropy hash: 26c9d319d4423d2555501d9ca0843af5
entropy source: MD5 of the letter, the BFUB field and the last three characters of the block 30 key, separated by spaces

Transactions

funding2019-04-130.007 BTC4431011443…6118c7
claim2019-04-130.00669491 BTCfdb692aeb0…0e6bb6

Hints

undated
officialQuestion: BItcoin Second
Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31
Published answer
Solution: A. (one capital letter).
Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31
undated
officialFormat: [solution] BFUB [BFUB] [link] with exactly one space between them and all words in answer capitalized.
Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31
Published answer
Finding BFUB: working from solution, develop hint. In this case Before B.
Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31
undated
officialPrevious block link digits: fTS
Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31
undated
officialFirst 2 digits of the hash are 26, so if you don't see those two digits, don't bother checking the BIP 39 tool.
Sourcereddit.com/r/bitcoinpuzzles/comments/bckvv9/easy_7_mbtc_quizchain_block_31