4 ms·

So the audio captcha was just two one-of-three challenges? How does this slow an automated bot down, it could just guess repeatedly and get it right 1/9th of th

by paulgb 3y ago

So the audio captcha was just two one-of-three challenges? How does this slow an automated bot down, it could just guess repeatedly and get it right 1/9th of the time.

valine 3y ago
I’m also fairly certain an FFT of the audio would instantly uncover the repeating patterns. The repeating tones would show up as taller spikes.
- plorkyeran 3y ago
  Yeah, that seems like something which is easier for a bot than a human.
- rnhmjoj 3y ago
  Even easier would be computing the autocorrelation: essentially you just slide two copies of the signal until they match.
  - lldb 3y ago
    That sounds an awful lot like convolution…
    - tgv 3y ago
      Which is easy with FFT.
flangola7 3y ago
Mine never lets me use the audio option. It says I have to complete the captcha.