privatekeycipher.php

См. документацию.

<?php
namespace Bitrix\Main\Security;

class PrivateKeyCipher extends AsymmetricCipher
{
    protected function doEncrypt($data, $key)
    {
        $success = openssl_private_encrypt($data, $out, $key);
 
        return $success ? $out : false;
    }

    protected function doDecrypt($data, $key)
    {
        $success = openssl_private_decrypt($data, $out, $key);
 
        return $success ? $out : false;
    }

    protected function getKeyInfo($key)
    {
        return openssl_pkey_get_details(openssl_get_privatekey($key));
    }
}