I have heard that Large Bitcoin Collider can only break into wallets that are created by broken software. My other question is that it seems the last private key that they found was on 2017-11-15 01:25:58 UTC. Am I right? Does it mean that their project is not successful any more?

  • Probably all broken keys are broken now, and it won't find anything anymore until someone ends up using broken software again to generate keys. Apr 8, 2019 at 19:03
  • @PieterWuille thank you for you answer Pieter. If someone hack the Electrum server can they manipulate our bitcoins?
    – Iman
    Apr 9, 2019 at 18:34

2 Answers 2


LBC exhaustively searches a relatively small area in the 256 bit private key space. It's not a general wallet cracker, broken or otherwise; rather, it will find a private key that is known to be in the vicinity of its searches. One example that sits in the blockchain is the so-called puzzle transaction, which was created to deliberately reward people who manage to crack successively more "difficult" keys. It may also discover some keys which were created in error - say, by a program (over)writing 32 random bits in the same memory location 8 times, instead of writing 32 random bits into 8 sequential locations - but it's not a general purpose wallet cracker.

I'm unsure if LBC is still in operation, but there have been subsequent keys in the puzzle transaction cracked, the most recent one (as I type this) in March 2019: https://www.blockchain.com/btc/tx/08389f34c98c606322740c0be6a7125d9860bb8d5cb182c02f98461e5fa6cd15

You can read more about the puzzle transaction here, including posts by the person that created it: https://bitcointalk.org/index.php?topic=1306983.0


See Why the Large Bitcoin Collider poses no threat to Bitcoin which explains some of the mathematics involved in an accessible way (perhaps overly so).

It gives an example of taking over the whole bitcoin network worldwide and spending $75 million on electricity every 3.5 days but taking 2,250,000,000,000,000 years to find one private key associated with unspent Bitcoin.

The LBC is no threat to any wallet which chooses private keys randomly - as they all should.

  • All this math is total desinformation. If you start bruteforcing private keys, you can find your first key at ANY time. But these 2,250,000,000,000,000 years (I didn't check probably with BITCRACK and modern hardware it is much faster now) is the time you are GUARANTEED to find at least one address. Feb 17, 2021 at 18:40

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