Post
Topic
Board Bitcoin Discussion
Re: == Bitcoin challenge transaction: ~1000 BTC total bounty to solvers! ==UPDATED==
by
cctv5go
on 30/10/2024, 06:35:08 UTC
Well by the same reasoning, puzzles from 81 to 159 don't make sense at all.
Frankly, I can't follow your logic why #81...#159 don't make sense for you.

..., because for example puzzle 254 would have somewhat similar difficulty as puzzle 127. But once #160 gets solved, then no one would be interested in solving 81 for a half-reward but double difficulty.
Why would puzzle #127 be of somewhat similar difficulty as puzzle #254? Can't wrap my head around this statement and it puzzles me. As I'm following the puzzle's progress only out of a crypto security inspired context and don't have much knowledge about BSGS and Kangaroo, maybe you're so kind to give a brief ELI12 type answer.


Because if you want to crack a private key by the BTC address, the only option is brute-force (e.g. 160-bit security at most).

But if you have to crack a private key by its public key, Kangaroo, BSGS, or even random sampling (b-day paradox) reduces the search to square-root, so e.g. 160-bit public key is somehow 80-bit secure. But since puzzles 81 to 159 (except multiples of 5) only have the address today, then there is no public-key secure equivalent puzzle to the 81, 82, 83, or 84 bits puzzle, and so on. So, brute-force grows exponentially, but the cost to break them is way higher than the prize. If we had equivalent higher public-key puzzles (165 bits, 170 bits) etc. with public key known, than they weren't actually 160-bits secure, but 82-bits, 85 bits, etc.) - the creator moved those funds way before we had Kangaroo publicly available, so the "160+ puzzles are all actually 160-bits secure" did not make sense at the time.

Puzzle 159 with no pub key is way overkill, it's simply measuring SHA256 cracking performance, not EC security. The highest puzzle that would actually measure EC security would have been #256 (128-bits secure).
你是谜题的参与者还是制作的?哈哈