On Sunday I wrote about Drupal 6 authentication with a FINeID card. In it I also claimed I was planning on expanding the Certificate Login module to facilitate an option for OpenID style identification, in which the user name doesn't need to be taken directly from the certificate but the user can instead be attached to any number of certificates. This is possible by using Drupal 6's authmap-table, which also Drupal's own OpenID module uses.
Months ago I acquired the Finnish FINeID smart card produced by the Police and Population Register Centre, even though plans about discontinuing it altogether have already been made. In addition to being a traditional identification card, it has a certificate that can be used for both authentication and signing documents – although quite few services actually support it (pretty much the only ones are public sector and Itella NetPosti – one bank did allow it for quite a while, but they discontinued it stating lack of use).