45 replies to this topic

[tibrewalalok92]

Captcha is an antispam technique promoted by google...it requires the human user to input two words in the box which r den verified by the computer if they r same...!..it also promotes digitalisation of old papers & journals as the words r chosed from them & on solving automatically gets added

[Heximal]

I've seen a lot of people doubt the reliability of Captcha (Re-Captcha, NUCaptcha and all variations) and its ability to tackle and prevent spambots, without taking one detail into account.

As Captcha services progress, enhance in security and complexity, so do said spambots. The general idea of every man-made creation is evolution and betterment. Captcha is a highly reliable service, but you could say spambots are highly reliable to their creators as well. New and improving ways to battle Captcha are found with each day and that's what makes Captcha seem unreliable, even though it's still the best we currently have.

[mrdee]

I have used some captchas in my day, and, as you say, after a while, it seems like the Spambots find their way around them.

I have used the ones with the nasty, almost impossible to read coloured letters, I also used the ones where people had to enter the answer to something like a sum (eg. 2+3=), then I also used something similar, but where people had to answer a question, but the answer was case sensitive.

I also used a captcha where the letters were struck through, but in the end, spammers found their way through.

I have now signed up for Google's Recaptcha,a free service where words, scanned from old books or old newspapers have to be entered.
It does look reasonably secure.

However, I am not sure if it can be used anywhere, I use it on two PHPBB forums I run, and there it is simple to enter the two keys (a private and a public one) you get from Google.

I am going to do a bit of further reading, as it is interesting stuff, and I will see if I can use it on more than PHPBB forums.

However, I would heartily recommend it.

[mrdee]

I found out it can be easily implemented into PHP scripts as well.
You can go here for further details and the appropriate code needed to implement it in your own scripts.

Edited by mrdee, 02 March 2012 - 02:58 PM.

[ellendaniell]

captcha is basically to stop spam. its quite an efficient way and is now being used in numerous websites. its got different forms such as adding, subtracting (basic mathematical calculations) and normally presenting the letters that the captcha displays. but the most annoying thing is sometimes its hard to read the label and one can end up typing in different letters and different numbers thereby causing a misunderstanding. this happens usually when the words are clustered or when its hard to tell the difference of whether its a lowercase or an uppercase letter. on the whole its for protection process and is widely used only because of its efficient "protection regime".

[xChellesei]

Just like what the other users say, it is a program that generates a challenge to confirm that the one registering to your website isn't a bot but a human. CAPTCHAs prevent spam posts or comments on blogs or forums and spam mails. The common CAPTCHAs are those that asks the user to type the generated text but there are also some CAPTCHAs that uses image. Personally, I like those image-based CAPTCHAs than text CAPTCHAs. Some text CAPTCHAs are quite hard to read while I find those image-based CAPTCHA, which will ask you to complete the puzzle, interesting. For me, they're easier than the common ones.

When I don't know anything about building websites, spams and these bots, I really thought that CAPTCHAs are totally annoying. I wondered what's the point of entering random texts that are sometimes unreadable. They also say "Are you human?" and I was like "What? Of course I am !". Spam bots never came to my mind. But now that I know their purpose, I don't get annoyed with these CAPTCHAs anymore even if some text are slightly unreadable.

Edited by xChellesei, 25 May 2012 - 11:50 AM.