Re: VC formats

Right, in the base media type. But SD-JWT describes a mechanism for
performing SD on JSON. It would be good to have a more transparent
mechanism to allow anchoring statements in something reference-able. It
seems a bit muddy now. Perhaps DIF, CCG, OIDF, and more can collaborate on
some rubric here.

On Tue, Mar 19, 2024 at 5:35 PM Orie Steele <orie@transmute.industries>
wrote:

> The VCDM is JSON-LD, and both JSON and RDF do not support selective
> disclosure in their base media types.
>
> SD-JWT only supports selective disclosure on JSON.
>
> ECDSA-SD only supports selective disclosure in JSON-LD (I think).
>
> MDoc only supports selective disclosure of in CBOR.
>
> There are basically 2 ways to secure media types... You can secure them in
> a media type agnostic manner, like JWS or COSE Sign1. Or you can secure
> them in a media type aware manner, like JWT, SD-JWT, mDoc, SD-CWT etc.
>
> The W3C VCDM is a media type that is built on +ld+json meaning it's always
> JSON-LD that you are securing... Regardless of how you secure it.
>
> OS
>
> On Wed, Mar 20, 2024, 10:27 AM Kim Hamilton <kimdhamilton@gmail.com>
> wrote:
>
>> Thanks for stating it clearly. This is why the statement "VCDM lacks
>> selective disclosure" trips the brain wires. It belongs at the
>> signature/proof level. And of course, selective disclosure can be performed
>> in different ways. Just wondering if I missed the boat on any
>> considerations that make the credential data model itself more or less
>> conducive to selective disclosure, which that statement appears to say.
>>
>> Or maybe it refers to a specific brand of selective disclosure, and not
>> selective disclosure in the general sense.
>>
>> Does SD-JWT-VC imply a landscape in which there will be a different VC
>> format for each signature suite? This is very different from my mental
>> model of VC data model, with the possibility of using different signature
>> suites. I'd be eager to learn more about the advantages of that.
>>
>> On Tue, Mar 19, 2024 at 5:10 PM Orie Steele <orie@transmute.industries>
>> wrote:
>>
>>> Selective disclosure is a property of the securing format, not the data
>>> model.
>>>
>>> Sd-jwt and ecdsa-sd both support selective disclosure, but with very
>>> different performance and security trade offs.
>>>
>>> It's not correct to say that CBOR, YAML, JSON, XML or JSON-LD support
>>> selective disclosure.
>>>
>>> It is correct to say SD-JWT, SD-CWT, mDoc, goridan envelopes or ecdsa-sd
>>> support selective disclosure.
>>>
>>> It seems jades as a requirement precludes the use of CBOR or Data
>>> Integrity Proofs, or even JWT, given JWTs are always compact (no JSON
>>> Serialization).
>>>
>>> OS
>>>
>>> On Wed, Mar 20, 2024, 9:53 AM Kim Hamilton <kimdhamilton@gmail.com>
>>> wrote:
>>>
>>>> Hi all,
>>>> I'm trying to get my head around the variety of VC formats. I ran
>>>> across this deck and I'm curious why it would say VCDM lacks selective
>>>> disclosure (included screenshot and deck). It does via signature suites, so
>>>> in a sense the statement "does not compute".
>>>>
>>>> Eager to learn about the new VC formats, similarities and differences.
>>>>
>>>> Thanks,
>>>> Kim
>>>> [image: Screenshot 2024-03-19 at 4.36.16 PM.png]
>>>>
>>>