Selective Disclosure in `kotlinx.serialization`

[iaik-jheher]

For any actual real-life wallet use case, we will need some kind of selective disclosure of credentials.

It would be very nice to extend kotlinx.serialization with redactable fields; essentially serialization for a Redactable<T> object (essentially a fancy optional) with serialization to JWP or some other (non-binary) merkle tree-like structure.

Not a very well-formed idea yet, but it'd be very convenient to be able to do

@Serializable
data class Credential(
  val firstname: Redactable<String>,
  val lastname: Redactable<String>,
  val dob: Redactable<String>)

and then have this serialize to a (partially-redacted) Merkle tree. I am also not sure how to best handle revealing of individual nodes after the fact; this sounds like it might need code generation (akin to what kotlinx.serialization already does?) to be done efficiently.

It's... an idea, not very well-structured yet. @JesusMcCloud told me to post it here either way.