...

1. Download the S/Notify mailer library component from https://download.savignano.net/snotify/jira/releases/
   (previous versions can be found in the subfolder archive)
   
   • net.savignano.s-notify.jira.mailer-x.x.x.jar
2. Copy the jar file to <YourJiraInstallationDirectory>/atlassian-jira/WEB-INF/lib 

Make sure that the the library component is readable by the Jira user. 

...

• User Settings – for users to view and optionally upload their own PGP key or S/MIME certificate
• Project Settings – for project administrators to view and optionally control encryption for emails referring to their projects

A Note On Encryption Strength

...

Quick Test 

The easiest and quickest way to verify the installation is 

...