Extending the Scope of CardSpace

Abstract

The recently-proposed PassCard scheme enables CardSpace to be used as a password manager, thereby both improving the usability and security of passwords as well as encouraging CardSpace adoption. However, this scheme does not work with sites using HTTPS, seriously limiting its practicality. In this paper we extend PassCard to support sites using both HTTP and HTTPS. Usernames and passwords are stored in CardSpace personal cards, and these cards can be used to sign on transparently to corresponding websites. PassCard does not require any changes to login servers, default browser security settings or to the CardSpace identity selector; in particular, it does not require websites to support CardSpace. PassCard operates with both the CardSpace and the Higgins identity selectors without any modification. We describe how this new version of PassCard operates, and give security and usability analyses.