Audio CAPTCHA with a Few Cocktails: It’s So Noisy I Can’t Hear You (Transcript of Discussion)

Abstract

Everyone, my name is Benjamin, and from being a Postmaster, which, probably, most of you aren't, at the moment, to a topic that, I guess, most of you dealed in the past, CAPTCHAs, and our topic is, audio CAPTCHAs, with a few cocktails, it's so noisy I can't hear you. First of all, you see a visual CAPTCHA and you think like adding some cocktails is pretty nice. So what's the general idea behind the system? Give me a second. Something is not working. So that's an audio CAPTCHA which is currently used and I guess most of you could solve, it? Frank Stajano: No. Reply: Yeah. So first of all, what's a CAPTCHA? CAPTCHA is Completely Automated Public Turing Test to Tell Computers and Humans Apart, and as you realise this one might be solved by a computer but probably not by anyone in this room, so it's not by definition a problem that humans are good at and computers aren't. So there's this Google reCAPTCHA problem, so the one you heard is an artefact from speech to text solvable CAPTCHAs of audio files in the past. In the past, audio CAPTCHAs were pretty easy to be solved by the reCAPTCHA. You just put in their audio transformation system and it could like solve every audio CAPTCHA, so they had to improve the audio CAPTCHA and you heard the improved version. Now the computer can't solve the problem but the human can't solve it either, because once they used concept noises like simple noises like white noise, in the background, first of all, or they used other regular noises like some sound just had changed but are on the same level. In the past, it was pretty easy, then they improved it and put more and more of this in the audio CAPTCHA and now it's not as easy as this question to answer like, Littlefoot's mother in the original Land Before Time, "Did you feel sad? Yes or no?" That would be a question we would expect for a CAPTCHA because it's easy for us to solve.