Completely Automated Public Turing test to tell Computers and Humans Apart used in form validation to restrict access to humans only
17
votes
3answers
1k views
If we know CAPTCHA can be beat, why are we still using them?
If we know CAPTCHA can be beat, why are we still using them?
A 35% to 90% success rate like wikipedia is stating means software is better at solving CAPTCHAs then I am.
7
votes
7answers
192 views
What type of captcha will you recommend?
What type of captcha will you recommend? I am looking mainly at usability, ease of use (development too), relatively secure
Usability
I find that those captcha with very curly words/numbers are ...
5
votes
12answers
1k views
Is there a true alternative to using CAPTCHA images?
Security is about balancing costs and risks, nothing is impossible to beat, specially not typical CAPTCHA implementations, but they do add something no other system seems to offer.
I've been reading ...
4
votes
5answers
358 views
Why re-verify with CAPTCHA on failed form entry?
Is there a reason for sites to ask for another CAPTCHA verification when some other part of the registration form, e.g. the username, was invalid?
4
votes
4answers
485 views
How does CAPTCHA mitigate DDoS attacks?
This seems like an easy question, but I've failed to find an answer.
One of the uses of CAPTCHA is to cope mitigate Denial of Service attacks. Suppose an adversary performs excessive login attempts, ...
4
votes
4answers
411 views
Why Do we Need CAPTCHA? In what case we should use it?
In what case we should implement Captcha based security?. How accurate it is and if there exists any alternatives for Captcha based Security.
3
votes
4answers
473 views
Can a CSRF CAPTCHA be defeated?
One defense that developers use to protect against a CSRF attack is to implement a CAPTCHA in critical steps. A CAPTCHA ensures that a human is at the keyboard approving the activity. But I've ...
2
votes
4answers
631 views
CAPTCHA or email confirmation?
I have read that captcha isn't a perfect solution to protect a website where for example the user can create an account, since there are many people in different countries that practicallty read ...
2
votes
2answers
117 views
Are these email captchas legitimate?
The last week, I've been getting this kind of emails to addresses that I don't use:
Dear Sir, Madam,
For security reasons and as part of our ongoing fight against spam, it is our policy not ...
1
vote
5answers
563 views
Anyone using Asirra in production? Are there similar alternatives?
The Asirra project is a Captcha alternative that shows you pictures of kittens and puppies to fend off bots and prove that the end user is a human.
Is anyone using Asirra (or something similar) in ...
1
vote
1answer
143 views
How reliable/secure is QCaptcha?
QCaptcha is an alternative way to protect a website from bots. It required a drag and drop action like this:
Question
How reliable is this implementation when compared to others mentioned on ...
1
vote
1answer
63 views
CAPTCHA Weakness to Automated Attack
EDIT: This question was dumb, I misread the quote that made me ask it. Sorry.
This is more of a follow up question from schroeder's answer to another question.
schroeder said that CAPTCHAs are ...
0
votes
5answers
96 views
Should I enforce a password policy on a web site?
For a commercial web site, is it important to impose some restriction on passwords to access the system?
Eg. special $char, Upper and lower case, numbers, at least a minimum length...
Can a CAPTCHA ...
0
votes
5answers
111 views
Good ways to prevent spammers from registering [duplicate]
Possible Duplicate:
Is there a true alternative to using CAPTCHA images?
Since everyone hates captchas what are good alternatives? I'm looking to prevent the automated creation of accounts ...
0
votes
1answer
165 views
Protect database resources from fake data inputs via web forms
Scenario:
I'm working on a project that needs to accept large amounts of data (customer data) from its users. So it can be normal to have a user trying to add 10,000 or 100,000 records at a time. In ...
0
votes
1answer
97 views
Can a Javascript - WebGL proof of work system prevent website spam?
Is it a good idea to come up with a Javascript-based Proof of Work system to reduce spam on forums, and other websites?
This idea would be similar to HashCash, but the computation would be based on ...
-4
votes
2answers
426 views
Is it possible to break captcha? [duplicate]
Possible Duplicate:
Can a CSRF CAPTCHA be defeated?
Is it to possible break captcha? If yes, how? If no, why websites use difficult captcha systems?
