How to check if mcrypt extension exists in php

Question

I would like to know the simplest and fastest PHP code line to check if mcrypt extension is available/installed.

There is a function that encrypts a string and first it requires to check if mcrypt is usable. If not, it will execute an alternative encrypt solution available on the system.

Thanks!

Have you searched to see if there is a generic PHP function that checks whether a function exists? — i alarmed alien, Aug 24 '14 at 22:28
Yes, you are right with that, but also I was looking for the fastest check code. — Heroselohim, Aug 24 '14 at 22:46
you can use some of the techniques from https://stackoverflow.com/questions/3131411/php-code-to-test-pdo-is-available — Elzo Valugi, Aug 08 '16 at 07:18

Charlotte Dunois · Accepted Answer · 2016-07-30T09:26:12.190

You can use function_exists to check if one of the mcrypt functions exists.

if(function_exists('mcrypt_encrypt')) {
    echo "mcrypt is loaded!";
} else {
    echo "mcrypt isn't loaded!";
}

Edit 30.07.2016:
Since my answer still gets a few upvotes from time to time, I benchmarked the performance of mine and Cristi Draghici's answers. The conclusion is, that function_exists is a bit faster than extension_loaded. https://3v4l.org/So4Ep

score 16 · Answer 2 · answered Apr 29 '15 at 07:26

16

You can also use extension_loaded():

if (extension_loaded('mcrypt')) {
    echo "mcrypt is loaded!";
} else {
    echo "mcrypt isn't loaded!";
}

answered Apr 29 '15 at 07:26

Cristi Draghici

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7
10

score 1 · Answer 3 · answered Jun 09 '17 at 01:10

If you are using a development environment like XXAMP, or WAMP, there should be a default "phpinfo" page. For example, in XXAMP it would be:

http://localhost/dashboard/phpinfo.php

You can also achieve this same screen by viewing a php file that has: phpinfo(); somewhere in the code.

In this screen, simply search for the string "mcrypt support". If installed, you will see a box that says "enabled".

How to check if mcrypt extension exists in php

3 Answers3

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