About The Puzzle
The puzzle
On 15 January 2015 someone made a single bitcoin transaction to 256 addresses. The private key of address number n was chosen from the range 2n-1 to 2n, so #1 has a 1-bit key, #2 a 2-bit key, and so on. The amounts grow with the size of the key. It works as a public measure of how far brute force can reach: each puzzle needs about twice the work of the one before.
Everything up to #70 has been solved. Puzzle #71 (address 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU) still holds about 7.1 BTC. Its key is one of 270 numbers, about 1.2 sextillion, between 0x400000000000000000 and 0x7fffffffffffffffff.
How the search works
For each candidate key the app computes the public key and the address and compares it with the target. There is no shortcut: the address does not give away anything about where the key is, so the range has to be checked one key after another. A modern CPU core checks several million keys per second.
The range is cut into blocks of 234 keys (about 17 billion). A task is one to four blocks. Your computer checks them and sends back its result.
Credit and prize sharing
Credit is given in proportion to the number of keys checked.
If the key is found, the coins are split: 20% is set aside for taxes, 40% goes to the project operator and 40% is shared by the volunteers who returned valid work, in proportion to their credit. It does not matter whose computer finds the key. Your current share is on your account page. If the coins are moved before we find the key, the search ends and there is nothing to share.
How the payout will work will be posted in the forums before anything is paid. Keep the email address on your account up to date.
What runs on your computer
The app runs on 64-bit Windows and Linux and uses the CPU only. It picks the fastest code your processor supports (SSE, AVX2 or the SHA extensions). One task uses all the CPU cores BOINC is allowed to use; to limit it, set "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 is planned.
Contact
Questions and problem reports go to the message boards or our Discord server.
