🔥 ~1000 BTC Bitcoin Challenge

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 #1–70 and #75, #80, #85, #90, #95, #100, #105, #110, #115, #120, #125, #130 private keys have already been cracked.

Original puzzle description from the creator:

"A few words about the puzzle. There is no pattern. It is just consecutive keys from a deterministic wallet (masked with leading 000...0001 to set difficulty). It is simply a crude measuring instrument, of the cracking strength of the community."

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 (tx) 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 transaction 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.

2023-04-16: somebody (maybe the owner) increased (tx) 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.

2024-09-12: puzzle #66 (6.6 BTC) was solved by 1Jvv4yWkE9MhbuwGUoqFYzDjRVQHaLWuJd (tx1) but the original spending transaction was replaced by bc1qpkp47q5cucrvnyepsdnjcv2kzyav5ze0ta7n67 (tx2) spending only 5.94 BTC. Another address 15XVN6hFkzGdUTY1XcsYKXxRezjARwyBQx took the rest of the prize: 0.66 BTC (tx3).

2025-02-21: puzzle #67 (6.7 BTC) was solved by bc1qfk357t8n045f8mwx672rx2re4pftm5gmjzdwq7 and the transaction was mined bypassing the public mempool to avoid interception as in the case of puzzle #66.

2025-04-06: puzzle #68 (6.8 BTC) was solved by bc1qfwpccz2udt3efk7y2wt9l44h34cs5yevjc80lk and the transaction was mined bypassing the public mempool to avoid interception as in the case of puzzle #66.

2025-04-30: puzzle #69 (6.9 BTC) was solved by bc1qlp0z45ctphhz0kywpmw3x2kjy7umhyfawxctah in less than one month, likely due to its position at the very beginning of the search range (0.72%). However, the original transaction (tx1) was publicly broadcast, leading to it being replaced multiple times (tx2, tx3, tx4). Ultimately, 15g7XHM6u921DvvPrgguxYkxDL8ruPGHXZ managed to steal the prize.

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 #67 (due to its narrower key space) or #135 (utilizing the Baby-step giant-step or Pollard's kangaroo algorithm because of the exposed public key).

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

• Use our GPU Cloud Search solution
• Generate random keys within the key space of puzzle #71 (not highly effective)
• Use Private Key Finder to scan the range of puzzle #71 in the browser (slow)
• Use KeyHunt for CPU search (example)

  71-bit puzzle search:

  ./keyhunt -m rmd160 -f tests/71.rmd -b 71 -l compress -R

  135-bit puzzle (BSGS) search:

  ./keyhunt -m bsgs -f tests/135.txt -b 135 -R

• Use Kangaroo for GPU search puzzles with exposed public key (limited to a 125bit interval search) (example)

  125-bit puzzle search:

  ./Kangaroo -gpu in125.txt

  Structure of the input file:

  Start range
  End range
  Key #1
  Key #2
  ...

• Use or BitCrack for GPU search (example)

  71-bit puzzle search:

  xxBitCrack.exe --keyspace 400000000000000000:7fffffffffffffffff -c 1PWo3JeB9jrGwfHDNpdGK54CRas7fsVzXU

• Join one of the collective solving pools

Links

• BitcoinTalk topic #1
• BitcoinTalk topic #2
• BitcoinTalk topic #3
• Overview of key cracking tools for 32BTC puzzle

Related puzzles

• Mini-puzzle for puzzle #120 SOLVED
• 80-bit private key puzzle SOLVED
• Mini-puzzle for puzzle #125 SOLVED
• Mini-puzzle for puzzle #130 SOLVED
• Mini-puzzle #4 SOLVED
• Mini-puzzle #5 SOLVED

Private Keys & Addresses

• Unsolved
• Solved
• All

Top Solvers

Bitcoin Challenge Odds Calculator

Entropy (bits)

Total Keys

Search Speed

Prefix Keys/s KKeys/s (10^3) MKeys/s (10^6) GKeys/s (10^9) TKeys/s (10^12) PKeys/s (10^15) EKeys/s (10^18) ZKeys/s (10^21) YKeys/s (10^24)

Calculate

The odds of finding a private key within:

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