On the Zend blog there's a new tutorial posted by Enrico Zimuel covering the use of libsodium in PHP 7.2 to provide stronger encryption for your data.
Recently, at ZendCon & OpenEnterprise 2018, I presented a session about the usage of Sodium in PHP 7.2. Here you can find the slides of this session.
The tutorial begins with an outline of the Sodium encryption including the algorithms it can use and how it helps to prevent side-channel attacks. It then lists out some of the common use cases and provides a simple code sample showing how to use it to encrypt a simple message with a randomly generated key.