Captcha and Security Queries

Captcha-prompt

Everyone knows the famous security checks, also known as Captcha, which are found on almost every page with a form. There are almost puzzles that are designed to prevent spamming.

There are different types of Captcha:

1st Captcha word. Here you must enter two words most, which are relatively difficult to read.

2nd Numbers and letters Captcha. Here, numbers and letters must be enziffert with patterned background.

3rd Questions captcha. For this you have to answer Captcha decipher anything but extremely simple questions / computing tasks.

Let me tell you something now about the different types of Captcha.
Everyone knows the classic version of Captcha, also called ReCaptcha:

This Captcha word is found on almost every page that contains a form.
However, it is difficult to decipher exactly what numbers and letters are displayed on the screen.

The advantage of this captcha is that it is virtually impossible for spammers to bypass this captcha.

The disadvantage is that it is barely readable for the human eye.

This captcha is easy to secure.

It is free to download the Captcha and easily integrate into your own website.

An alternative would be to this Captcha, called Securimage:

It's a numbers and letters Captcha.
Captcha This has the advantage that it is legible.

The downside is that it is therefore easier for spammers, making it unsafe.

Click here for the official page (http://www.phpcaptcha.org/) and download directly here (http://www.phpcaptcha.org/download/)

A letter Captcha would be this:

It is, in my opinion, hard to read. Therefore safe, but in the long run just annoying.

Last but not least, I would like to present you the questions-Captcha:

This captcha is in my opinion the most sensible and most effective Captcha, as each person can answer these questions.

The disadvantage is that this captcha only includes computing tasks.

It would be good to involve other issues that are accessed randomly.

So this is, in my opinion, the safest, simplest and yet captcha.
Also a very good alternative to ReCaptcha.

The last two Captcha can be found here (http://www.stoppt-den-spam.info/webmaster/captcha-tutorial/index.html)