Add digital signatures to PDF documents - GUI and CLI, cross-platform
Implementation of the EDIINT AS2 protocol (RFC 4130)
UFONet - Denial of Service Toolkit
Java application for encryption
Tiny application which allows encrypting basic text.
Centralized signing and verification
GMR digital signature system
Open Source PKI solutions
CrococryptQuerl is a web-based file encryption & transfer tool
Encrypting, anonymous, unlimited size message transfer system