🔥 ~1000 BTC Bitcoin Challenge Transaction

Description

In 2015, in order to show the hugeness of the private key space (or maybe just for fun), someone created a "puzzle" where he chose keys in a certain smaller space and sent increasing amounts to each of those keys like this:

2⁰ ≤ random key < 2¹ — 0.001 BTC
2¹ ≤ random key < 2² — 0.002 BTC
2³ ≤ random key < 2³ — 0.003 BTC
...
2²⁵⁵ ≤ random key < 2²⁵⁶ — 0.256 BTC
(total 32.896 BTC)

First 65 and #70, #75, #80, #85, #90, #95, #100, #105, #110, #115, #120 private keys have already been cracked.

History

2015-01-15: a transaction was created containing a transfer transaction for 256 different Bitcoin addresses.

2017-07-11: funds from addresses #161—256 were moved to the same number of addresses of the lower range – thus increasing the amount of funds on them.

2019-05-31: the creator of the "puzzles" creates outgoing transactions with the value of 1000 satoshi for addresses #65, #70, #75, #80, #85, #90, #95, #100, #105, #110, #115, #120, #125, #130, #135, #140, #145, #150, #155, #160 with the aim of probably comparing the difficulty of finding a private key for the address from which such a transaction was carried out, and one that there is no transaction.

2022-04-16: somebody (maybe the owner) increased the unsolved puzzles prizes again by x10. Now the puzzle #66 prize is 6.6 BTC, #67 is 6.7 BTC and so on... puzzle #160 prize is 16 BTC.

Solution

In order to solve the puzzle, you must iterate over the specific private key space and check each private key for balance. The narrower the key space, the greater the chance of finding the private key. Currently, it is better to focus on solving puzzle #66 (due to its narrower key space) or #125 (utilizing the BSGS algorithm because of the leaked public key).

To automate this process, you can utilize the following methods/tools:

• Generate random keys within the key space of puzzle #66 (not highly effective)
• Use Private Key Finder to scan the range of puzzle #66

• Use KeyHunt for CPU search:

  66-bit puzzle search:
  ./keyhunt -m rmd160 -f tests/66.rmd -b 66 -l compress -R

  125-bit puzzle (BSGS) search:
  ./keyhunt -m bsgs -f tests/125.txt -b 125 -R

• Use or BitCrack for GPU search:

  xxBitCrack.exe --keyspace 20000000000000000:3ffffffffffffffff -c 13zb1hQbWVsc2S7ZTZnP2G4undNNpdh5so

• Join TTD's 66-bit puzzle solving pool

Links

• Original transaction
• BitcoinTalk topic #1
• BitcoinTalk topic #2
• BitcoinTalk topic #3

Private Keys & Addresses