Broken link in Glossary under Encryption definition

## Problem

On the Glossary page for the Encryption definition, the text "For more on different kinds of encryption, you can look here" links to https://ssd.eff.org/en/node/36 which is has a 404.

I'm not sure which page it was originally linking to but it could be: 
- https://ssd.eff.org/module/key-concepts-encryption
- https://ssd.eff.org/module/what-should-i-know-about-encryption