Doge's Gambit

December 11, 2020, 22:11 UTC. Crypto Puzzlers uploads Doge's Gambit, 68 seconds of a chess board, and nine minutes later posts it on r/dogecoin. "I tried something new in that there are really two puzzles in one". The previous one posted there went in a few hours, so this one is a bit harder.

A bit. The Ether lasted four months, the Doge five, and in those months Dogecoin did what Dogecoin did in 2021.

Doge's Gambit, two puzzles in one video

Two prizes, two chains, two keys. The video description lists 10,000 DOGE at DRMqy4… and 0.01 ETH plus 49 BOMB at 0x7777F6…. Difficulty 6 out of 10, says the author. All three were funded in the half hour before the upload.

The board is an 8 by 8 grid, so it's a chess board, and the pieces are coins. The Dogecoin logo is a knight. Ether is a rook, Bomb Token is a bishop, and a spirograph plays the queen. That last one, the author admits later, has nothing to do with anything. Just a symbol that looked right. The squares carry hex digits and letters in white, pink, yellow, green, blue and red, and four numbered stars on top give the colours an order.

Sixteen frames, and every frame is a different board.

Where the two puzzles split

Put the pieces to work. Every frame has two yellow, two green, two blue and two red squares that some piece can move to, and two of each colour that no piece can reach. Reachable squares feed the Dogecoin key. Unreachable ones feed the Ether key. Same frames, same board, two answers.

That's why one commenter asked twice about "few private keys". The confusion was the design.

How the Ether and Bomb Token key was solved

The first solution video goes like this:

1. Sort the sixteen frames by the sum of the digits on white squares. They add up to 1, 2, 3 and so on to 16.
2. In each frame keep only the coloured squares no piece can reach, two per colour.
3. Add each pair of the same colour modulo 16, and read the four sums in star order: yellow, green, blue, red.

Frame one gives yellow 5 + 2 = 7, green 1 + 7 = 8, blue 7 + e = 5 and red 8 + 8 = 0. That's 7850, the first four hex digits of the key. Sixteen frames, four digits each, 64 hex characters. The modular addition is the part the author calls the trickiest, and the one the author was glad to have put in, since the prize kept growing while nobody got it.

Is the answer right?

puzzles verify doges-gambit/eth derives 0x7777F6… from the key shown on screen. And the chain agrees in its own way: the public key recovered from the signature of the claim transaction is the same one.

The gas ate half the Ether

April 23, 2021, 14:32 UTC. The first move is the 49 BOMB, 48 to a new address, because Bomb Token burns 1% of every transfer and 1% of 49 rounds up to one whole bomb. That transfer cost 0.004759827 ETH in gas. Ten minutes later the Ether follows, 0.003308173 ETH after another 0.001932 in fees.

So of the 0.01 ETH prize, less than a third made it out. Spring 2021 gas, everybody.

How the Dogecoin key was solved

The second solution video takes the other half of the board:

1. Sort the frames by the number of pink squares, starting from the one with a single pink square.
2. Keep the coloured squares a piece can move to.
3. Drop every one that doesn't touch a blue square. Diagonals count.
4. Read the rest in order of how many blue squares each one touches.

Frame one keeps 6, J and e, touching one, two and three blue squares. That's 6Je, and a Dogecoin WIF for an uncompressed key starts with a 6. Frames don't all give the same number of characters, which must have been fun to find out the hard way. One of the later frames spells RLY, and the video points it out.

How long did the Dogecoin part take?

Five months after the upload the 10,000 DOGE left DRMqy4… on May 9, 2021, at 00:28 UTC, 9,999 to one address and 1 DOGE in fees. The solver wrote to the author that it took about a month of work. The author's own tally of the prize: around $50 at funding, $400 in January, five or six thousand dollars on the day it was claimed. Nice month.

puzzles verify doges-gambit/doge derives the address from the WIF on screen, and the public key in the claim's input script matches it too.

Who solved it?

Nobody publicly. Both solution videos congratulate "the person who solved it" and neither gives a name. The records leave the solver out.

The first Dogecoin records

Doge's Gambit is where dogecoinPuzzle gets its first user. Base58 P2PKH under Dogecoin's own version byte, WIF under its own too, so a Bitcoin WIF of the same key fails on this record, as it should. Balances aren't there yet: no @agntn/explorers provider reads Dogecoin, so balance() rejects with UnsupportedChainError before any request. The chain history above comes from the transactions on the record.

What the records carry

export const dogesGambitDoge = dogecoinPuzzle({
  id: "doges-gambit/doge",
  address: p2pkh("DRMqy4bGAnWpaShBFtTUoHEiBWj4HoiSfq", "ddcbc240…3ebd20a4"),
  sourceUrl: VIDEO,
  startedAt: "2020-12-11 22:11:10",
  status: Status.Solved,
  pubkey: uncompressed("0488e79f…66ad695766"),
  key: wif("6Je1sv5tRwXLFKpnor4yef6i4k73eJu2Kw9DEnRLY3BL9jVtPq3"),
  prize: 10000,
  hints: [official("This is the first time I put two puzzles in one, …", VIDEO, undefined, { date: "2020-12-11", answer: answer("The same board, read the other way: …", SOLUTION, …) })],
  transactions: [funding(/* 2020-12-11 */), claim(/* 2021-05-09 */)],
  assets: assets({ puzzle: "puzzle.jpg", solution: "doge-key.png", sourceUrl: VIDEO }),
});

The Ether record is the same shape on ethereumPuzzle, with hex(...) for the key and two claims: the BOMB transfer with 0 ETH moved, then the Ether. BOMB itself isn't in prize, because a record counts one currency. It's here on the page instead.

The keys come from the author

Both keys are the ones the author typed on screen in the solution videos, not something the repo worked out. assets/doges-gambit/ keeps those two frames next to the video's thumbnail, and assets/sources/doges-gambit/ keeps both r/dogecoin threads with every comment, in case Reddit loses them.

Browse the Doge's Gambit records