phpMyAdmin error “Error: Undefined constant “SODIUM_CRYPTO_SECRETBOX_KEYBYTES”” (SOLVED)

On Arch Linux, when trying to use the phpMyAdmin 5.3 pre-release, I encountered an error:

Error: Undefined constant "SODIUM_CRYPTO_SECRETBOX_KEYBYTES"

Checking in Debian showed that there is no such problem with phpMyAdmin 5.3.

The reason for the error is that sodium support is not enabled.

How to enable sodium on Arch Linux (Manjaro, BlackArch)

To enable sodium support in Arch Linux and derivative distributions (Manjaro, BlackArch) follow these steps.

Install the php-sodium package:

sudo pacman -S php-sodium

Open the /etc/php/php.ini file:

sudo gedit /etc/php/php.ini

Find the line in it

;extension=sodium

and uncomment it to get:

extension=sodium

Restart the web server for the changes to take effect:

sudo systemctl restart httpd.service

This will enable sodium support and the error in phpMyAdmin 5.3 will disappear.