Environment - PHP extension sodium

From MoodleDocs

The php-sodium extension provides strong encryption capabilities in an easy and consistent way.

Note that, for sites not having the extension installed, a php-openssl based solution, considered sub-optimal, is used, and this fallback will stop working in Moodle 4.2. See MDL-71421 for more details.

Hence, it's highly recommended to start using php-sodium.

It might be useful to copy the \server\php\libsodium.dll library to \server\apache\bin\libsodium.dll - as mentioned in https://moodle.org/mod/forum/discuss.php?d=444514

See also https://www.php.net/manual/book.sodium.php and https://py-ipv8.readthedocs.io/en/latest/preliminaries/install_libsodium/