What is The Puzzle?

The Puzzle is a volunteer computing project working on the Bitcoin puzzle. In 2015 someone sent bitcoin to a series of addresses whose private keys were picked from deliberately small ranges: the key for puzzle #1 is 1 bit long, #2 is 2 bits, and so on up to 160. The small ones were found long ago. Puzzle #71 is the lowest one still unsolved. Its key is somewhere between 2⁷⁰ and 2⁷¹, and the address holds about 7.1 BTC.

There is no shortcut for this one, just checking keys one after another, and there are a lot of them (2⁷⁰ is about 1.2 sextillion). We split the range into blocks of 2³⁴ keys, roughly 17 billion each, and hand them out through BOINC. Your computer checks a block and sends back an encrypted result, which is verified before any credit is given.

Prize sharing. If the key turns up, the coins are split like this: 20% is set aside for taxes, 40% goes to the project operator and 40% goes to the volunteers. The volunteer part is divided between everyone who returned valid work, in proportion to their credit. It does not matter whose computer actually finds the key.

About the odds: the range is huge, and nobody can say how long it will take or whether we will get there first.

The app runs on 64-bit Windows and Linux. GPU versions run on NVIDIA cards, AMD Radeon and Intel graphics.

More about the puzzle, the search and prize sharing

Join The Puzzle

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Search progress

Puzzle #71's range holds 2⁷⁰ keys, about 1.18 sextillion.

Search speed, last 30 days

Billion keys per second. Times are UTC; the lighter bar is today so far.

The key is equally likely to be anywhere in the range, so the next task has the same chance of containing it as any other. The search does not need to reach 100%: it ends as soon as the key is found, by us or by anyone else.

News

Badges are here
You asked for badges, so here they are. They appear next to your name in the forums and on your account page, and they're updated once a day.

Keys checked. Each step means you've checked 32 times more keys than the step before, and your badge shows the highest step you've reached:

- 2^35 keys: 200 credit
- 2^40 keys: 6,400 credit
- 2^45 keys: 204,800 credit
- 2^50 keys: 6.6 million credit
- 2^55 keys: 210 million credit
- 2^60 keys: 6.7 billion credit

These count all the credit you've ever earned here, so you keep them when we move on to the next puzzle. Nobody has reached 2^55 yet.

Founding volunteer. This one goes to the first 100 people with credit on the project, and it's yours to keep. 30 places are still open, so return your first valid result to claim one.

Discoverer of puzzle #71. Reserved for the volunteer whose computer finds the key. It's the only one of its kind. It doesn't change the prize split, which is still shared in proportion to credit, but it does give you the bragging rights.

Badges are included in our statistics export as well, so they may start showing up on stats sites too.

Thanks for all the work you're putting in, and good luck!
6 Nov 2026, 13:32:31 UTC · Discuss

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Prize rules clarified
Prize distribution rules have been clarified to address edge cases highlighted by the participants. They did not change materially; small prize amounts, claim window and taxes have been clarified.
31 Oct 2026, 21:04:57 UTC · Discuss

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The Puzzle is open to the public
The Puzzle is now open to everyone. Attach to https://thepuzzle.cloud/ in BOINC, or add it from your TheScienceCloud account, where it is now listed as a project.

What we are doing
In January 2015 someone sent bitcoin to 256 addresses whose private keys were chosen from deliberately small ranges. Everything up to #70 has been solved. Puzzle #71 (address 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU) still holds about 7.1 BTC. Its key is one of 2^70 numbers, about 1.2 sextillion. There is no shortcut, so the range has to be checked one key at a time. We split it into blocks of 2^34 keys (about 17 billion) and send them out as BOINC tasks.

What runs on your computer
The app runs on CPUs under 64-bit Windows and Linux. One task uses all the CPU cores BOINC allows; you can limit this with "Max # of CPUs for this project" in your project preferences. It needs a few MB of memory and almost no disk space. A GPU version for NVIDIA cards is in testing.

If the key is found
20% is set aside for taxes, 40% goes to the project operator and 40% is shared by everyone who returned valid work, in proportion to their credit. It does not matter whose computer finds the key. Details are on the About page. Please keep the email address on your account up to date.

Questions and problem reports go to the message boards or our Discord server.
30 Oct 2026, 9:03:35 UTC · Discuss

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