Bitaps mnemonic challenge

IDbitaps05 / 511 puzzle · 2020-06-19

Collection

Bitaps mnemonic challenge

bitcoin

A 3 of 5 secret sharing scheme with two shares published.

Author: Bitaps
Prize recorded: 1.00016775 BTC
Still unsolved: 1 · 1.00016775 BTC

closed 0 / 1

Census

unsolved: 1100%
public keys: 1100%
private keys: 00%

Access

LoadgetCollection("bitaps")

Showbitaps in the playground

The puzzle

Bitaps split a mnemonic into five shares with a threshold of three. They published two of them and the account's zpub, and put a bitcoin on the first receiving address. Three shares recover the seed. Two don't, by construction. So the challenge is a statement about the scheme as much as a bounty: you can't get there from what's public.

What the records carry

The one record in the collection is the only one with shares on it:

tssrc/collections/bitaps.ts

export const bitapsPuzzle = puzzle({
  id: "bitaps",
  chain: "bitcoin",
  address: "bc1qyjwa0tf0en4x09magpuwmt2smpsrlaxwn85lh6",
  sourceUrl: "https://bitaps.com/mnemonic/challenge",
  startedAt: "2020-06-19 13:24:41",
  pubkey: compressed("0385a3a591451ed7ed6c90dae882db918107d6f906d270cf4728d168126e0e89aa"),
  key: derivation("m/84'/0'/0'/0/0")
    .xpub(
      "zpub6qdEDkv51FpxX6g1rpFGckmiL46vV8ccmtEgPAkj3qj8N4ZZHyXDRA9RwpTiFK2Kb8vRaDmSmwgX6rfB4t2K8Ktdq8ExQ6fumKpn2ndJCqL",
    )
    .shares(3, 5, [
      share(1, "session cigar grape merry useful churn fatal thought very any arm unaware"),
      share(
        2,
        "clock fresh security field caution effort gorilla speed plastic common tomato echo",
      ),
    ]),
  prize: 1.00016775,
  transactions: [
    funding("a24e…25e6", "2020-06-19 13:24:41", 1),
    increase("bb0b…f167", "2021-11-29 12:20:03", 0.00008781),
    increase("fe3f…c14d", "2022-02-05 20:43:56", 0.00002403),
    increase("910c…b272", "2022-10-13 00:48:34", 0.0000522),
    increase("c617…3419", "2026-02-01 14:34:35", 0.00000371),
  ],
});

The public key is known because the zpub gives it. The private key isn't. A path plus an xpub is no secret, so hasPrivateKey() says false. The four top-ups since 2020 are on the record as increase transactions. That's why the prize has change on the end.

Status

Open, and a singleton. The id is bitaps, bitaps.get() takes no argument, and get("bitaps") at the top level finds it too.

The record

The one puzzle in this collection, the way its page shows it.

IDbitaps2020-06-19

Puzzle / bitaps

bitcoinp2wpkh unsolved

Record

puzzle({
  chain: "bitcoin",
  address: "bc1qyjwa0tf0…xwn85lh6",
  key: derivation("m/84'/0'/0'/0/0").xpub("zpub6qdEDkv5…n2ndJCqL").shares(3, 5, [share(1, "session ciga… unaware"), share(2, "clock fresh …ato echo")]),
})

Prize: 1.00016775 BTC
Key material: none published
Verification: unverifiable
Solved: not yet

tx 5

Trail: Explorerblockstream.info; Sourcebitaps.com/mnemonic/challenge; Trybitaps in the playground

Address: bc1qyjwa0tf0en4x09magpuwmt2smpsrlaxwn85lh6

hash160 249dd7ad2fccea67977d4078edad50d8603ff4ce

Balance

asking the explorer

Key

public key · compressed: 0385a3a591451ed7ed6c90dae882db918107d6f906d270cf4728d168126e0e89aa
derivation path: m/84'/0'/0'/0/0
extended public key: zpub6qdEDkv51FpxX6g1rpFGckmiL46vV8ccmtEgPAkj3qj8N4ZZHyXDRA9RwpTiFK2Kb8vRaDmSmwgX6rfB4t2K8Ktdq8ExQ6fumKpn2ndJCqL
secret sharing: 3 of 5 shares, 2 published
share 1: session cigar grape merry useful churn fatal thought very any arm unaware
share 2: clock fresh security field caution effort gorilla speed plastic common tomato echo

Transactions

funding2020-06-191 BTCa24e37411d…9925e6
increase2021-11-290.00008781 BTCbb0b6c3198…c8f167
increase2022-02-050.00002403 BTCfe3f6d1f45…2ec14d
increase2022-10-130.0000522 BTC910c4c6af9…a1b272
increase2026-02-010.00000371 BTCc6178e5541…943419

Techniques

shamir-sharespuzzlebitaps.com/mnemonic/challenge

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