3 ms·

Mining is solving some kind of puzzle. If not a lot of blocks get mined, the difficulty the puzzle is reduced. This way the system automatically balances so min

Mining is solving some kind of puzzle. If not a lot of blocks get mined, the difficulty the puzzle is reduced. This way the system automatically balances so mining a block costs about as much as you gain when you solve the puzzle first.

gjvc 4y ago
I do wish people would not use the term "puzzle" when talking about bitcoin and proof-of-work. The word "puzzle" conveys some sort of strategy and approach beyond trial-and-error. Instead of a puzzle, it is a brute-force search.
- deleted 4y ago
  [deleted]
- nullc 4y ago
  > it is a brute-force search That usually causes people to assume its a finite haystack with a single needle, e.g. something that has progress, and bitcoin mining doesn't. A lottery is a better analogy but carries its own misunderstandings. All analogies are imperfect. :)
  - tinus_hn 4y ago
    It’s a huge but finite haystack with a lot of needles, the number of needles depends on the difficulty.
    - nullc 4y ago
      Internal state of sha256 is 512 bits, though the inputs the user can control are limited to about 300 bits. In any case, it's larger than the believed number of atoms in the observable universe. The important point is that there is no progress, each attempt has an independent probability of success. Imagining it as an infinite haystack with a difficulty controlled density of needles still yields the right understanding.
- acjohnson55 4y ago
  I think of it more like a raffle. But yeah, I share your frustration. Writers fixate on finding the right analogy instead of focusing on the actual problem being solved: randomly choosing a block decider out of an open set of candidates, with no central selection infrastructure.
- tromp 4y ago
  Would you say that other proof of work puzzles such as Cuckoo Cycle [1], which asks for a fixed length cycle in a large random bipartite graph, is a brute force search as well? Because that one is certainly not solved by trying all possible cycles. [1] https://github.com/tromp/cuckoo https://github.com/tromp/cuckoo

gjvc 4y ago

I do wish people would not use the term "puzzle" when talking about bitcoin and proof-of-work. The word "puzzle" conveys some sort of strategy and approach beyond trial-and-error. Instead of a puzzle, it is a brute-force search.

deleted 4y ago
[deleted]
nullc 4y ago
> it is a brute-force search That usually causes people to assume its a finite haystack with a single needle, e.g. something that has progress, and bitcoin mining doesn't. A lottery is a better analogy but carries its own misunderstandings. All analogies are imperfect. :)
- tinus_hn 4y ago
  It’s a huge but finite haystack with a lot of needles, the number of needles depends on the difficulty.
  - nullc 4y ago
    Internal state of sha256 is 512 bits, though the inputs the user can control are limited to about 300 bits. In any case, it's larger than the believed number of atoms in the observable universe. The important point is that there is no progress, each attempt has an independent probability of success. Imagining it as an infinite haystack with a difficulty controlled density of needles still yields the right understanding.
acjohnson55 4y ago
I think of it more like a raffle. But yeah, I share your frustration. Writers fixate on finding the right analogy instead of focusing on the actual problem being solved: randomly choosing a block decider out of an open set of candidates, with no central selection infrastructure.
tromp 4y ago
Would you say that other proof of work puzzles such as Cuckoo Cycle [1], which asks for a fixed length cycle in a large random bipartite graph, is a brute force search as well? Because that one is certainly not solved by trying all possible cycles. [1] https://github.com/tromp/cuckoo https://github.com/tromp/cuckoo