As of PHP 7.2.0 this extension is bundled with PHP. For older PHP versions this extension is available via PECL.
In order to use this extension you must compile PHP with sodium support by using the --with-sodium[=DIR] configure option.
In order to use this extension you have to add extension=php_sodium.dll to php.ini.
Information zur Installation dieser PECL-Extension finden sie im Kapitel Installation von PECL-Extensions. Zusätzliche Informationen wie neue Releases, Downloads, Quelldateien, Maintainerinformation und ein CHANGELOG finden Sie hier: » https://pecl.php.net/package/libsodium