How to fix «Undefined offset: 2 in vendor/magento/framework/Encryption/Encryptor.php on line 588» in Magento 2.3.2?

[dmitry_fedyuk (Dmitrii Fediuk)]

You need to install the PHP sodium extension.

2.3.2 installed and bin/magento setup:upgrade not working

Magento 2.3.2 Undefined offset Encryptor.php

[dmitry_fedyuk (Dmitrii Fediuk)]

For PHP FPM 7.1 in Debian/Ubuntu:

apt-get install php7.1-sodium
service php7.1-fpm restart