4 ms·

Captchas are not just ddos protection, and even if it were, the botnets don't send tons of spam from any single device. Otherwise it's too easy to identify and

• Kiro 3y ago
  That's why you use something like this, where each request incurs a cost for the attacker so it doesn't matter if the origins are distributed.
  • hot_gril 3y ago
    The attacker doesn't have to calculate the puzzles in one central place. It can do that on the hacked devices.