How to check if mcrypt extension exists in php

php function encryption exists mcrypt
Heroselohim picture Heroselohim · Aug 25, 2014 · Viewed 27.8k times · Source

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!

Answer

Charlotte Dunois picture Charlotte Dunois · Aug 25, 2014

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

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