在windows中找不到libmcrypt.dll和php_mcrypt.dll

I installed php using xampp. But php_mcrypt.dll not found in the php/ext folder. libmcrypt.dll also not found in php folder. How can I install libmcrypt.dll and php_mcrypt.dll?

Below is the screen capture of the two files that are not found: php_mcrypt.dll not foundlibmcrypt.dll not found