There has been several attempts to solve this bit range Puzzle
https://bitcointalk.org/index.php?topic=5218972.0 through bruteforce of PrivateKey either the Address itself or the PubKeys through Kangaroo and BSGS algos.
This thread is another approach (a very slow one) which goes through the exact same procedure by which these puzzles were generated at the first hand. Creating the Wallet -> Mnemonics -> Seed -> List of Privatekeys -> Masked Privatekeys -> Check for known privatekeys collision.
Code :
https://github.com/iceland2k14/btc_words/blob/main/seed_puzzle.pyThis is more of an alternative exercise where if successful then all the remaining puzzles of ~ 1000 BTC will be solved all together. I know the probability of success is nearly zero. But still wanted to try to see how fast we can do it and what are the hurdles in this way. Any existing tool with what speed?
There are some assumptions which i think maybe correct/incorrect. Every opinion with logic could help in understanding more.
1. Wallet was new and puzzles 1-256 should corresponds to the Address index 0 to 255 from the wallet. Creator is very careful in making it. So this assumption maybe correct.
2. These Keys are sequentially generated by masking deterministic wallet privatekeys. So if any collision can be found with 10 masked Keys that is most likely the Correct seed.
3. The Puzzles are from year 2015 so the entropy bits could be either 128 or at max 192. Very little chance for 256.
4. Mnemonics used might have been English words, most probabilistic scenario.
5. Keys are generated using the standard BIP44 path with No Hardened Address route.
Assumption 2, 3, 4, 5 are dynamic and can be changed in the code easily. But if assumption 1 is incorrect then it is more difficult.
BTW, Just in case if the collision happens then you would see a result something like this image.