As I’ve been developing an STS code library I’ve noticed a few inconsistencies around how people assume PPIDs work. If you’ve never read the interoperability specification now is a good time to start. If you’ve implemented Information Card support on your web site you’ll be aware of the Personal Private Identifier (PPID) claim. It’s generally described as a unique ID that identifies a combination of an information card and the relying party the claims are being sent to. Vittorio, as ever, has more details. On the surface the usual description indicates that each relying party gets an individual PPID, and...