Version 1.78.1 is available upstream. Please consider updating! It seems that version 1.78.1 is available upstream, while the latest version in the Gentoo tree is 1.77-r1. You think this warning is false? Read more about it here.
The Bouncy Castle Java S/MIME APIs for handling S/MIME protocols. This jar contains S/MIME APIs for JDK 1.8 and up. The APIs can be used in conjunction with a JCE/JCA provider such as the one provided with the Bouncy Castle Cryptography APIs. The JavaMail API and the Java activation framework will also be needed.