pam_pkcs11 is a login module allowing a X.509 certificate
based user login. The certificate and its dedicated private
key are thereby accessed by means of an appropriate PKCS#11
module. For the verification of the users' certificates,
locally stored CA certificates as well as either online or
locally accessible CRLs are used.

PAM-PKCS#11 package provides:

A PAM module able to:
    Use certificates to get user credentials
    Deduce a login based on provided certificate
Several tools:
    Standalone cert-to-login finder tool
    Certificate contents viewer
    Card Event status monitor, to trigger actions on card insert/removal

These changes are made under the sponsorship from the FreeBSD Foundation.

WWW: https://github.com/OpenSC/pam_pkcs11