This is an old authentication backend and works with dokuwiki up to Andora Belle 2012-10-13 For newer dokuwiki releases an auth plugin is required. You have to update this backend to an auth plugin: authsmartcard Plugin (as successor of smartcard)

This auth backend enables smartcard logins to dokuwiki.

• You can use multiple authentication backends eg. LDAP, AD and Plain (search and modify against them all)
• Allow username and password login and Smartcard login or only Smartcard login

• User don't have to remember passwords on different infosystem
• Safer (username-password combination can be logged etc, Smartcard keys are only on smartcard:))

• https://github.com/mxrguspxrt/dokuwiki-smartcard-authentication

(If something is unclear, create issue and I'll try to make it better.)