AWS Encryption SDK
Open source alternative to Auth0 / Firebase Auth, etc.
The OWASP ZAP core project
OWASP Coraza WAF is a golang modsecurity compatible firewall library
AWS Encryption SDK
Sign PDF with Digital Signature Certificate
Mkpass - Command line Secure Password Generator
A Collection of Useful Java/Swing Code
Open source version of Google Authenticator (except the Android app)
Role Based Access Control System
pythonic kerberosish ticket system: easy to use, easy to subclass