Replacing "captcha"?

Question

CAPTCHA

Is it worth removing the "captcha" and using, for example, a check for the time of sending - say, less than 5 seconds - just a bot.
What other options are there?

Answer 1

Give a link to the IQ test, there are a lot of questions, if you answer in less than 20 minutes - send nafig. If you score less than 90 points - send nafig (either a bot or an idiot), if you score more than 130 - also send nafig (either a bot with answers to an IQ test, or a genius who will still be bored on your site).

Answer 2

Unfortunately, the bot can wait between 5 seconds and 10. You should be doing a Turing test that only a human can pass. By "captcha" you apparently meant only a test in the form of character recognition. Then there are alternatives:
1. Speech recognition.
2. Recognition of a graphic image, counting the number of objects of the same type.
3. The answer to the riddle, mathematics, continue the stable expression.

Answer 3

On my sites I use a question during registration, which is selected randomly from the list of questions, and in addition the captcha itself. Bots have not been seen for 3 months.

Answer 4

notcaptcha.webjema.com/

Answer 5

counting the number of similar items.

In :) Exactly... Three numbered pictures are given, the task is to find an extra one... Only the numbers are not one, two, three, but something more serious and different on each captcha... So that it does not break through randomly.

Answer 6

You can search the database of proverbs and sayings, place asterisks in one of the words and ask what the word is. Maybe even from the list.

Answer 7

Generate a javascript expression that will be evaluated by the user agent (browser) and the response will be added to a hidden form field.
From a custom-written bot, this will not help, from mass ones it’s easy.
If you correctly approach the solution of this issue, you can get a high-quality solution.

Answer 8

Ask "what time is it".

Answer 9

1. Manual pre-moderation (manually check the first N comments of the user)
2. Service like Akismet
3. I also read about testing comments with special sets of rules. For the presence of more than N links in the text - a penalty of 5 points. For the presence of words from the prohibited list (porn, viagra, etc.) there is still a fine. For short comments like "thank you" or "hello! cool blog" is also fine. Etc. As a result, the total amount is viewed and the comment is discarded or published. Unfortunately, I can't remember the link to the original article.