What is LBC?

The "Large Bitcoin Collider" (LBC — a nod to the Large Hadron Collider) is a distributed computing project that searches for private key collisions in the Bitcoin address space. The project systematically generates private keys within a continuous 2160 range and computes their corresponding addresses, checking each against a database of known funded Bitcoin addresses. Should a collision occur, the finder gains cryptographic access to those funds.

For the story of how LBC evolved from a humble Perl script checking addresses against a hash table to a GPU-accelerated distributed system processing billions of keys per second, see our History.

Is This Legal? Is This Even Possible?

Both valid questions. Searching for colliding private keys is not illegal anywhere we are aware of. However, claiming possession of funds discovered this way may be considered theft in some jurisdictions — consult local laws before making any decisions. As for possibility: the pool has already found several private keys. The evidence is on the Trophies page.

Why Do This?

Because "impossible" is a hypothesis worth testing. Throughout history, many things deemed impossible turned out to be merely difficult. This project is the empirical counterpart to the theoretical security assumptions underlying Bitcoin. For the mathematics behind collision probability and our search strategy, see Theory.

Why Use a Pool Instead of Going Solo?

Efficiency. In auto mode, the client receives only work intervals that have not been searched by any other participant. Solo searching risks duplicating effort on already-inspected ranges — reducing your effective probability to zero for those blocks. The pool ensures every cycle of your hardware explores uncharted territory. Additionally, the LBC client is currently the fastest collision-finding software publicly available.

How Do I Know the Pool Is Not Scamming Me?

All cryptographic operations happen locally on your machine. The server coordinates work distribution but never sees the actual key generation or matching. When your client finds something, it writes immediately to your local FOUND.txt file and displays on screen — no server communication required. You can verify this yourself: run LBC against a known range, disconnect from the network, and observe.

If I Find a Private Key, Can I Keep the Funds?

Legally, this depends on your jurisdiction. In many places, taking 100% would constitute theft. Some jurisdictions may permit claiming a finder's fee (typically 5-10%). Consider whether a smaller legal share is preferable to a larger illegal one. IANAL — seek proper legal counsel.

Ethically, note that some addresses belong to non-profit organizations (like 1Archive1n2C579dMsAu3iC6tWzuQJz8dN of the Internet Archive). Seizing funds from charitable organizations would be poor form regardless of legality. Bitcoin "ownership" is defined by possession of the private key, but social norms still apply.

What Should I Do If I Find Something?

First, transfer the funds to a custodial address you control. This step is critical because the pool's search wavefront is public information. If you announce before transferring, any bad actor could re-derive the key from the known interval and transfer the funds before you do.

Then, announce the find publicly. This gives the rightful owner an opportunity to prove their claim to the funds. If you transfer and do not announce — intending to keep the funds — your actions may be considered theft. The announcement opens a legitimate path for resolution.

Note: The pool logs which client searched which interval and from which IP address. Should a rightful owner later prove their claim, this information may be provided to assist in resolution.

Gkeys Forfeiture and LBC Pot Payout

Historical policy on work forfeiture and pot distribution. This system was retired in late 2017. See the History page for archived details.

Notable Dates

For specific finds and discoveries, see the Trophies page.

  • 2017-10-30: 8000+ tn keys searched, Gkeys forfeiture, Pot payout
  • 2017-10-16: GPU performance improvement: ~28% speedup
  • 2017-09-01: End of GPUAuth4All initiative
  • 2017-08-01: LBC first anniversary. GPUAuth4All launched
  • 2017-04-23: 52 bits covered, 4280 tn keys searched
  • 2017-04-09: 51 bits covered, 2140 tn keys searched
  • 2017-03-25: 50 bits covered, 1120 tn keys searched, >500 Mkeys/s
  • 2017-03-23: 1000 tn keys milestone
  • 2017-03-09: 49 bits covered, 560 tn keys searched
  • 2017-01-27: 48 bits covered, 280 tn keys searched
  • 2016-11-11: 47 bits covered, 140 tn keys searched
  • 2016-10-21: 46 bits covered, 70 tn keys searched, ~70 Mkeys/s
  • 2016-10-09: 45 bits covered, 35 tn keys searched
  • 2016-10-01: 44 bits covered, 17.65 tn keys searched
  • 2016-09-27: 43 bits covered, 8.75 tn keys searched, 23.5 Mkeys/s
  • 2016-09-25: 42 bits covered, 5 tn keys searched, 18.8 Mkeys/s
  • 2016-09-23: 41 bits covered, 3 tn keys searched
  • 2016-09-21: 40 bits searched
  • 2016-09-20: New client prototype: 13x speedup
  • 2016-09-19: Second bounty found (claimed ~20h later)
  • 2016-09-18: Windows bug discovered and fixed. Pool rollback
  • 2016-09-17: Stats page with 24h find probability
  • 2016-09-14: 500 bn keys (1 tn addresses) searched
  • 2016-09-10: New client: 3x speedup
  • 2016-09-07: Windows client released
  • 2016-08-29: First pool bounty found
  • 2016-08-10: Pool inception, ~0.15 Mkeys/s
  • 2016-07-28: Standalone client: 36 bits searched