Add digital signatures to PDF documents - GUI and CLI, cross-platform
Free and open-source PDF signing and verification application.
Managed .NET wrapper for unmanaged PKCS#11 libraries
OpenSC - tools and libraries for smart cards
GUI tool for administration of PKCS#11 enabled devices
AVR based smartcard/token with ECC and RSA cryptography
Certificate Authority administration application
PKCS#11 logging proxy module
OpenPGP is a smart card/java card standard for signing and encrypting.