SOP/Crypto-encoding

A PHP implementation of RFC 7468 textual encodings of cryptographic structures (PEM).

Including SOP/Crypto-encoding php library in Joomla

There is code example for Joomla 3 and Joomla 4.

<?php 
defined('_JEXEC') or die('Restricted access');

// For Joomla 3

JLoader::registerNamespace('Sop', JPATH_LIBRARIES);

// OR 
// for Joomla 4
JLoader::registerNamespace('Sop', JPATH_LIBRARIES. '/Sop');