What is the purpose of StructuredDocuments?

[DRK3]

Why not just encode your data as an JWE and directly put it in an EncryptedDocument instead of wrapping it in a StructuredDocument first, seeing as how the server never sees the StructuredDocument. A StructuredDocument are already a very general object.

Now... assuming that Structured Documents are here to stay... I find the ID constraint strange. In the description for the StructuredDocument id property, it says:

An identifier for the structured document. The value is required and MUST be a Base58-encoded 128-bit random value.

Seeing as a StructuredDocument is encrypted before being put in an EncryptedDocument what is the need for the format constraint on the id property? Why does a StructuredDocument have an ID anyway?

[DRK3]

Discussed on July 8, 2021 WG call:

Do we need the ID in a structured document?

• Clients may want to use ID for indexing/caching
• Could meta be used for these purposes?
• Is the ID being in a structured document an artifact of a specific implementation?
• Use case: relating structured doc to encrypted doc
• Mandate that Structured Doc ID is identical to the encrypted doc ID.
• Maybe structured document should also have the sequence number from encrypted document?
• Document migration: Do IDs change?
• Update spec to say that you only encrypt the meta, content and stream (if applicable) fields. An implementation may provide fields like id in the structured document that match what's in the encrypted document
• Implementations may augment the structured document on their end.
• First few examples could include only required fields, and then an example with those augmented fields.

[dmitrizagidulin]

Discussed on Sep 2, 2021.

There are two issues here:

1. Does the EDV spec want to be able to reserve keys, in structured documents?
2. Clarifying the algorithm for generating encrypted indexes.

[dlongley]

The algorithm for generating encrypted indexes can be found here: #56 (comment)

It should be checked against the edv-client implementation for any updates.