A further note for everyone, unless something drastically improves with being able to use a public key, such as BSGS, Kangaroo, etc., the 67, 68, and 69 wallets, are all easier reached (time wise) now versus 135.
The lower puzzles are now very risky ... Even if someone manages to crack one of them still they could be easily stolen.
It's better not to find a solution than get it and then being robbed right away.
Hello. I just found out about this puzzle.
If the funds are to be transferred to a different wallet, can you or anyone else explain in layman's how can they be stolen?
Very easy... Confirming a tx on btc blockchain takes some time to process (sometimes quite long time).
Sending btc from address exposes their public key. Normally it's not a problem - but with artifically reduced private keys to lower bit range (like 67 bit) it's a matter of seconds to crack the private key from the exposed public key (with kangaroo or BSGS method)
Cracking the private key gives the attacker the opportunity to use RBF (replace by fee) to redirect the transaction to another address.
Nobody know how many bots constantly monitoring mempool and waiting to one of those public keys show up - then they will start to crack the private keys and use RBF to steal btc (some of them probably can constantly monitoring even the replaced transaction to replace it again with higher fee in case other bot is trying to steal it to --- that all leads to some sort of bot wars).
So if you somehow manage to crack the puzzle with low bit range think twice before moving it cause for sure someone will try to steal it from you. If you simply transfer it they will be stolen for 100% and all your effort will bring you nothing but frustration... Puzzle 66 was already stole (at least it looks so).