IDcollectionsQuizchain2

quizchain2/4

Solved on 2019-05-13 after 1h 24m, 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 four letter word

May 13. "Looking for a four letter word. Yes, quite safe for work." Format [solution] TOMI [TOMI], no link. The post says why: the solution and TOMI field have enough entropy on their own. The real reason comes later.

The prefixes: 9ac for the whole string, 2 for the answer, 9 for the TOMI field. And a warning: "either very easy if you get the method or impossible if not."

MasK

Look at the block 3 key. L488KiS3jUut79rDM6gwxUdg7Qm1SXwQnMasKLpzFzb6KrNLsFpT. See it? Right there, MasK. Once you see it, you can't unsee it.

That's why there's no link. With the block 3 key in the format, the word would jump out at you. The author had done this before, with Hoax and hit in first run keys. And this one fits the theme. Privacy was Bitcoin's original purpose, so a mask is a pretty good word to find.

u/puzzleponky had it in an hour. The claim confirmed at 13:57:44 UTC. The full string is MasK TOMI previous block private key. They tried the whole key as the TOMI field first, expecting a twist. No luck, so a few more tries.

Nobody printed this key. The record derives it.

IDquizchain2/404 / 102019-05-13
Puzzle / quizchain2

4

bitcoinp2pkh solved

Record 

bitcoinPuzzle({
  address: p2pkh("1C1e2wvP5p6J…cUXLudNQ", "78c84c353224…b14935fd"),
  status: Status.Solved,
  key: wif("L3PyFkCsVdej…rSi69hfz").entropy("9acb509e171c…82648bdc", source("https://www.…block_4/")).derived(),
})
Prize
0.007 BTC
Key material
wif, derived from the recipe
Verification
verified
Solved
2019-05-13 · 1h 24m
tx 2
Trail
Explorerblockstream.info
Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4
Tryquizchain2/4 in the playground
Address
1C1e2wvP5p6JRyV4BtRHjprCuBcUXLudNQ

hash160 78c84c353224ce0bfcbc9eab8f64201ab14935fd

Balance
asking the explorer

Key

public key · compressed
0385f0b820b4a7de14503b97a86b61904f1ffde8beae67a7b131f8265dd37a0828
WIF
L3PyFkCsVdej9qktSKZvfYqzmxes6SWRvGeAqoS4jxirrSi69hfz
entropy hash
9acb509e171c3baaf8ad1fa982648bdc

Transactions

  1. funding2019-05-130.007 BTC7446567ec9…bb82b9
  2. claim2019-05-130.00679648 BTC12f20e5e03…96a25e

Hints

  1. undated

    officialQuestion: Looking for a four letter word. Yes, quite safe for work.

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4

    Published answer

    Once you see the word in the previous block private key, it becomes easy. That is the reason I did not include a link, since it would become too obvious.

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4

  2. undated

    officialFormat: [solution] TOMI [TOMI]

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4

    Published answer

    MasK TOMI previous block private key

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/comment/enbxj6y

  3. undated

    officialFirst three digits of MD5 hash: 9ac

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4

  4. undated

    officialFirst digit of solution only MD5 hash: 2

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4

  5. undated

    officialFirst digit of TOMI field only MD5 hash: 9

    Sourcereddit.com/r/bitcoinpuzzles/comments/bo356q/7_mbtc_quizchain2_block_4

ID@agntn/puzzlesv0.26.0MIT license

Public data about public puzzles. Balances come from the chains' explorers through the worker, cached for five minutes. Every key here was public before it landed in a record.