Re: == Bitcoin challenge transaction: ~1000 BTC total bounty to solvers! ==UPDATED==

I see puzzles 65, 70, 75, 80 ... 125 are solved. How come?

It's easier to solve a key if you know the public key, when someone spends from his address, public key associated with that address is revealed, this is what Satoshi did with puzzles every 5 key apart, methods such as kangaroo and BSGS can be used to speed up the search thousands of times faster than brute forcing for unexposed puzzles.

That's why you should never keep your coins on addresses with known public keys.😉 ( not that any time soon they can crack 256 bit keys, so every one is safe for a few decades )

But maybe someday you have to make an outgoing transaction. So after this transaction you need to transfer a rest of your bitcoins to another address without any outgoing transactions to be sure that your public key is not revealed?

That's the best security precaution, think of public keys as actual keys of safe vaults, and think of hackers/ attackers as keysmith, given enough time and resources they can make a duplicate and open the vault, but if they never see the key, they can't duplicate it.