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> The idea that all of us could together could crack RSA keys wasn't just a thought exercise, people signed up and did it. Hasn’t changed that much. Here we ar

> The idea that all of us could together could crack RSA keys wasn't just a thought exercise, people signed up and did it. Hasn’t changed that much. Here we are in 2023 where most of this distributed power goes to cracking sha 256 hashes. Just for speculation and profit instead of leaderboards.

chungy 4y ago
Bitcoin has nothing to do with "cracking SHA256 hashes", for what it's worth. The only thing remotely related is how it brute-forces inputs until it generates hashes that begin with a certain number of bits set to 0.
- hot_gril 4y ago
  It's continually testing the strength of SHA256. If you can find a way to even partially crack it, you win money. Edit: Also, way more hashes are happening all the time now, increasing the chance that someone finds a collision if it were possible.
  - chungy 4y ago
    That's still not what the Bitcoin miners are doing. They're manipulating inputs, trillions of times a second, just to match a "magic" target for a SHA256 hash starting with a certain number of bits set to 0. Cracking hashes would imply that they're taking pre-existing hashes and reversing them to find the input.
    - hot_gril 4y ago
      Hashes have multiple requirements for security. You're talking about only one facet, which is that you cannot be given a hash and produce a matching input without consulting a rainbow table (I think there's a term for this, I forget it though).
      - IncRnd 4y ago
        Chungy is correct though. Bitcoin has absolutely nothing to do with "cracking sha256 hashes". Bitcoin hashes until the correct output is found. There are double hashes, but that is solely to avoid collisions and has nothing to do with determining the plaintext from a known digest.
        thfuran 4y ago
        >and has nothing to do with determining the plaintext from a known digest. So why'd you bring it up?
        deleted 4y ago
        [deleted]
        squeaky-clean 4y ago
        User bitcoinistrash is the one that brought it up, and they're spreading incorrect information about how it works. Cracking sha256 hashes implies trying to reverse a specific hash. There are literally thousands (millions?) of potential inputs that hash to a valid bitcoin mining block output. It's basically a race to find the first one matching the rules of the current block difficulty. The goal isn't to produce any one specific input/hash pair.
        glass3 4y ago
        In which context would somebody try to reverse a hash? That would be like arbitrarily enhancing a bad-resolution image to see something that cannot be seen. Hash collision should always be about finding matching content for a hash.
        deleted 4y ago
        [deleted]
        postalrat 4y ago
        And if you cracked the math of sha256 you wouldnt need to search you would just calculate one of the inputs to produce whatever you want. All zeros would be as easy as one.
- cypress66 4y ago
  > hashes that begin with a certain number of bits set to 0. This myth was always intriguing to me. Where does it come from? It's not a number of 0s (which would imply difficulty could only be doubled or halved), it's just finding a hash that is less than the target.
  - kevinwang 4y ago
    It's in the original Bitcoin whitepaper
    - chungy 4y ago
      Thanks, this is likely where I read it first. I hadn't realized the actual implementation got more complicated than that. :)
    - cypress66 4y ago
      Interesting. Even though I read the paper many times, I didn't catch that. I guess I always skipped that part because I assume I already knew it.
  - pmarreck 4y ago
    "Less than the target" in effect is "more leading zeroes" depending on how low the target is. But the lower, the more leading zeros, Right?
hot_gril 4y ago
Yeah, cryptocurrency stuff is the closest I've ever felt today to the spirit of the old internet.
- SECProto 4y ago
  > cryptocurrency stuff is the closest I've ever felt today to the spirit of the old internet Cryptocurrency feels like the exact opposite of the old internet to me - it feels like a bunch of anonymous bros looking for the next sucker to scam out of money and get rich quick.
  - wvoch235 4y ago
    The nature of the scam has evolved, and possibly the parties involved have changed, but the scams were always there.
  - Breza 4y ago
    I agree with you. The early web was full of amazing opportunities but had trouble monetizing things. Cryptocurrency is the opposite, it tries to monetize everything but doesn't have practical uses.
    - fho 4y ago
      Bitcoin was "old internet" tech at some point. Just for reference, I bought my first BTC at 0.20 €/BTC. Back then it looked like the future to a lot of us ... "hey! We/Hackers can make our own money. And it is superior to state issued money!" ... looking back, it honestly it is somewhat to see the state of cryptocurrencies today.
      - landoftheice 4y ago
        [dead]
      - RobotToaster 4y ago
        I thought it was a dumb idea at the time, that nobody would be stupid enough to invest in. I still think it's a dumb idea, but I've learnt not to underestimate human stupidity.

chungy 4y ago

Bitcoin has nothing to do with "cracking SHA256 hashes", for what it's worth. The only thing remotely related is how it brute-forces inputs until it generates hashes that begin with a certain number of bits set to 0.

hot_gril 4y ago
It's continually testing the strength of SHA256. If you can find a way to even partially crack it, you win money. Edit: Also, way more hashes are happening all the time now, increasing the chance that someone finds a collision if it were possible.
- chungy 4y ago
  That's still not what the Bitcoin miners are doing. They're manipulating inputs, trillions of times a second, just to match a "magic" target for a SHA256 hash starting with a certain number of bits set to 0. Cracking hashes would imply that they're taking pre-existing hashes and reversing them to find the input.
  - hot_gril 4y ago
    Hashes have multiple requirements for security. You're talking about only one facet, which is that you cannot be given a hash and produce a matching input without consulting a rainbow table (I think there's a term for this, I forget it though).
    - IncRnd 4y ago
      Chungy is correct though. Bitcoin has absolutely nothing to do with "cracking sha256 hashes". Bitcoin hashes until the correct output is found. There are double hashes, but that is solely to avoid collisions and has nothing to do with determining the plaintext from a known digest.
      - thfuran 4y ago
        >and has nothing to do with determining the plaintext from a known digest. So why'd you bring it up?
        deleted 4y ago
        [deleted]
        squeaky-clean 4y ago
        User bitcoinistrash is the one that brought it up, and they're spreading incorrect information about how it works. Cracking sha256 hashes implies trying to reverse a specific hash. There are literally thousands (millions?) of potential inputs that hash to a valid bitcoin mining block output. It's basically a race to find the first one matching the rules of the current block difficulty. The goal isn't to produce any one specific input/hash pair.
        glass3 4y ago
        In which context would somebody try to reverse a hash? That would be like arbitrarily enhancing a bad-resolution image to see something that cannot be seen. Hash collision should always be about finding matching content for a hash.
        deleted 4y ago
        [deleted]
        postalrat 4y ago
        And if you cracked the math of sha256 you wouldnt need to search you would just calculate one of the inputs to produce whatever you want. All zeros would be as easy as one.
cypress66 4y ago
> hashes that begin with a certain number of bits set to 0. This myth was always intriguing to me. Where does it come from? It's not a number of 0s (which would imply difficulty could only be doubled or halved), it's just finding a hash that is less than the target.
- kevinwang 4y ago
  It's in the original Bitcoin whitepaper
  - chungy 4y ago
    Thanks, this is likely where I read it first. I hadn't realized the actual implementation got more complicated than that. :)
  - cypress66 4y ago
    Interesting. Even though I read the paper many times, I didn't catch that. I guess I always skipped that part because I assume I already knew it.
- pmarreck 4y ago
  "Less than the target" in effect is "more leading zeroes" depending on how low the target is. But the lower, the more leading zeros, Right?

hot_gril 4y ago

Yeah, cryptocurrency stuff is the closest I've ever felt today to the spirit of the old internet.

SECProto 4y ago
> cryptocurrency stuff is the closest I've ever felt today to the spirit of the old internet Cryptocurrency feels like the exact opposite of the old internet to me - it feels like a bunch of anonymous bros looking for the next sucker to scam out of money and get rich quick.
- wvoch235 4y ago
  The nature of the scam has evolved, and possibly the parties involved have changed, but the scams were always there.
- Breza 4y ago
  I agree with you. The early web was full of amazing opportunities but had trouble monetizing things. Cryptocurrency is the opposite, it tries to monetize everything but doesn't have practical uses.
  - fho 4y ago
    Bitcoin was "old internet" tech at some point. Just for reference, I bought my first BTC at 0.20 €/BTC. Back then it looked like the future to a lot of us ... "hey! We/Hackers can make our own money. And it is superior to state issued money!" ... looking back, it honestly it is somewhat to see the state of cryptocurrencies today.
    - landoftheice 4y ago
      [dead]
    - RobotToaster 4y ago
      I thought it was a dumb idea at the time, that nobody would be stupid enough to invest in. I still think it's a dumb idea, but I've learnt not to underestimate human stupidity.