Authenticator length

[BasileiosKal]

A Token has an authenticator of constant length (Nk). For BBS, the authenticator is a proof generated by ProofGen. The proof's size depends on the number of disclosed attributes.

How can this be defined??

• Define Nk to be N/A in the IANA registry and the authenticator to be something like uint8_t authenticator<0..2^32>??
• Remove the authenticator and add a proof field??
• Define a constant number of selectively disclosable items, like [sid, iat, nonce]?? Or not use attributes at all??

[wbl]

Where does this get defined? It's not the in the architecture draft which is the main thing I looked at when writing our text.

[BasileiosKal]

Yes sorry! I was going of the HTTP Authentication and Issuance Protocol documents (was trying out the http protocol).

[wbl]

https://www.ietf.org/archive/id/draft-ietf-privacypass-auth-scheme-11.html#section-2.1-5 says tokens may change the type of the message, so I think Nk being NA and changing the type is fine