An accessor function interfaces among a client, a relying party, and an identity provider. The identity provider can “manage” personal (i.e., self-asserted) information cards on behalf of a user, making the personal information cards available on clients on which the personal information cards are not installed. The client can be an untrusted client, vulnerable to attacks such as key logging, screen capture, and memory interrogation. The accessor function can also asked as a proxy for the relying party in terms of invoking and using the information cards system, for use with legacy relying parties.