GnuPG - GnuPG is a complete and free implementation of the OpenPGP standard as defined by RFC4880 (also known as PGP).
The Security Checklist - The Practical Security Checklist for Web Developers
Kleopatra - Kleopatra is a certificate manager and GUI for GnuPG.
SafeBase - SafeBase is the interactive security portal to share your security posture, automate access to sensitive compliance information, and subscribe to vendor security program updates.
PGP Tool - PGPTool allows you to encrypt and decrypt files. It's free and easy to use.
WordPress Security Scanner - Check if your WordPress site has known vulnerabilities