Engine_pkcs11 is a PKCS#11 engine for OpenSSL. It can be loaded using code,
config file or command line and will pass any function call by openssl to a
PKCS#11 module.

Engine_pkcs11 is meant to be used with smart cards and software for using
smart cards in PKCS#11 format, such as OpenSC. Originaly this engine was a
part of OpenSC, until OpenSC was split into several small projects for
improved flexibility.