Here is How I did it.
- Download the libsodium from here > For PHP 7.0, For PHP 5.6 And For PHP 5.5 (All x64). #One Important Note, Please download appropriate x86-32 bit or x64-64 bit of this extension matching of your environment from here
- Extract the Downloaded file and copy libsodium.dll to wamp->bin->php->php5(x).x.xx Folder
- Copy php_libsodium.dll From the extracted File to wamp->bin->php->php5(x).x.xx ->ext
- Now Click on the WAMP System tray icon.
![enter image description here](https://i.sstatic.net/M5QGl.png)
- Go to PHP-> PHP Settings and Click on the enable dl from the menu of the WampManager from the system tray
- Now Add bellow line to php.ini from PHP -> php.ini from the menu of Wampmanager, save and close it
extension=php_libsodium.dll
- Now Restart Apache or click Restart All Services from the menu of WampManager
You should now get your php_libsodium in the extensions of the php Up and Running.
:)
**I didn't notice that, this question is 4 months old. I hope You have solved this.