pkcs11-helper is a library that simplifies the interaction with PKCS#11 providers for end-user applications. pkcs11-helper allows using multiple PKCS#11 providers at the same time, enumerating available token certificates, or selecting a certificate directly by serialized id, handling card removal and card insert events, handling card re-insert to a different slot, supporting session expiration and much more all using a simple API. pkcs11-helper is not designed to manage card content, since object attributes are usually vendor specific, and 99% of application need to access existing objects in order to perform signature and decryption. WWW: https://github.com/OpenSC/pkcs11-helper