It should probably have random words in all capitals in each question. The way it is, if a question has a word in all caps, that's the answer.
...and also has 1 in 1 chance of automated recognition.
TextCAPTCHA: 180 million simple logic questions
51–60 of 66 posts
Re: TextCAPTCHA: 180 million simple logic questions
#52I've thought about this issue before (and proof-of-concepted a similar system, see http://www.blahedo.org/botblock/ ), and came to similar conclusions, but there's an important difference: A crucial part of making this a successful anti-spam system is that it is a moving target. Every user of the system must be able to write their own questions. If that happens, the spammer's task is intractable. But if there is a ce…
I've often wanted my own text-based CAPTCHA for a video game website I run. I'd ask things like "What is the name of the purple weapon?" or "How many shields do you start with?" People who actually play the game could nail questions like that, while bots would be up a creek.
Re: TextCAPTCHA: 180 million simple logic questions
#53At one point I was getting spammed through a contact form ( http://hhgproject.org/contact.cgi ) so I added two forms of a text based captcha---the first one is a single question (that anyone visiting that particular page should know) and a hidden field (via CSS) that should not be changed. I haven't received a spam since.
Re: TextCAPTCHA: 180 million simple logic questions
#54I tried breaking this captcha. Here are some experimental results and mathematics: By applying the mathematics from the Birthday Attack ( http://en.wikipedia.org/wiki/Birthday_attack ), If an attacker is able to solve 15.8 million of the 180 million captchas, there will be a 50% probability that the attacker can beat the captcha. I tried refreshing the page 10 times, generating a total of 100 captchas. Out of those,…
Can you explain how the birthday paradox applies here? Just looking at it simply, if you can solve 15.8 of 180, that means that for any given test you should have an 8.77% chance of solving it (6 tests for > 50%). What am I doing wrong? Also, it looks like some of the other questions are easy to automate. Like "how many letters are in the word 'whatever'".
A Birthday Attack relies on the fact that even for some rare events (such as two random people having the same birthday), when there is a large opportunity to observe the rare event (such as 30 random people in the same room) it's actually quite likely to observe the event.
Re: TextCAPTCHA: 180 million simple logic questions
#55[deleted]
Re: TextCAPTCHA: 180 million simple logic questions
#56I've thought about this issue before (and proof-of-concepted a similar system, see http://www.blahedo.org/botblock/ ), and came to similar conclusions, but there's an important difference: A crucial part of making this a successful anti-spam system is that it is a moving target. Every user of the system must be able to write their own questions. If that happens, the spammer's task is intractable. But if there is a ce…
I've often wanted my own text-based CAPTCHA for a video game website I run. I'd ask things like "What is the name of the purple weapon?" or "How many shields do you start with?" People who actually play the game could nail questions like that, while bots would be up a creek.
What if one of your fans created a simple bot specifically designed to answer your admittedly easy questions?
Re: TextCAPTCHA: 180 million simple logic questions
#57Some of the questions don't have one globally unique answer, for example: which day is a part of the weekend, Sunday, Friday or Monday. Where I live (Israel), Friday is part of the weekend, were as I bet the creator of the list lives in the USA and as many times happens, believes the USA==World and the "correct" answer is probably Sunday.
Stop bombing palestinian children and we'll start giving a fuck about what you call the weekend.
Friday is part of the weekend for Palestinian children too.
Another problem with this system is that it only works for people who can read and understand English.
Re: TextCAPTCHA: 180 million simple logic questions
#58Earlier quoted context omitted.
I don't get how the answer could be 6, though I do agree with you on the paradox of CAPTCHAs
Interpretation 1: It's a string list and pick the first element = 25. Interpretation 2: It's a numerical list of numbers, numbers being ordered by value have an implicit sort applied to them, pick the first element in that sequence = 6. #2 is a very programmer thing to do ;)
you get a cookie :)
Re: TextCAPTCHA: 180 million simple logic questions
#59Very cool, this is one of my favorite types of captchas, because I don't have to sit and squint at the screen trying to figure out what the heck I'm supposed to type. Is it an I, or a 1? Is it an S or a 5?
The problem is, it turns out computer programs feel exactly the same way.
Re: TextCAPTCHA: 180 million simple logic questions
#60I would be interested to see what the completion rate for this is versus, e.g., the Yahoo captcha. My intuition is "not that great." (You require reading on the Internet... uh oh.) By the way, picking one token from the captcha and returning it beats the captcha 7% of the time, if the examples are representative. Spammer wins, since he can generate requests by the hundreds of thousands.
Maybe the solution is to obscure the text somehow, so that a spammer can't read the text to grab a token . . . .
Do remember you really need to consider the blind in any solution.