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Re: CBOR-LD for VC

From: Dmitri Zagidulin <dzagidulin@gmail.com>
Date: Mon, 14 Feb 2022 16:15:01 -0500
Message-ID: <CANnQ-L73hBdALNYohiuPq-5XHRGfy+My1nZ-nggtMSKLSkQz0g@mail.gmail.com>
To: Christopher Allen <ChristopherA@lifewithalacrity.com>
Cc: Joel Thorstensson <oed@3box.io>, Anders Rundgren <anders.rundgren.net@gmail.com>, W3C Credentials CG <public-credentials@w3.org>
I don't think the new version of CBOR-LD has any component of, or relation
to, IPLD.

We ended up using it in the MIT DCC credential wallet (open source),
because it provides the best compression mechanism for VCs that's out there
currently (significantly better than gzip etc, or hand-assembled CBOR).
(I think the New Zealand govt uses it for their Covid qr codes, too.)

On Mon, Feb 14, 2022 at 1:49 PM Christopher Allen <
ChristopherA@lifewithalacrity.com> wrote:

> On Mon, Feb 14, 2022 at 2:18 AM Joel Thorstensson <oed@3box.io> wrote:
>> Would be interesting to explore what the intersection of CBOR-LD, VCs,
>> and IPLD would be. IPLD is a dataformat for hash linked data. It specifies
>> a DAG-CBOR encoding which uses tag 42 to represent a hash link (which imo
>> is pretty much the only way you can responsibly do linked data).
> We decided not using the old version of CBOR-LD as it was a mishmash of
> JSON-LD & IPLD, plus a little CBOR. Could be a newer version is better, but
> we are very uncomfortable in supporting IPLD in the mashup.
> We don’t have a replacement but are investigating a number of more CBOR
> centric approaches, COSE, CSF (
> https://test.webpki.org/csf-lab/home), or maybe one of our own
> tentatively called crypto-envelope that supports both signatures &
> encryption, and allows for partial signatures, multisig, transcryption,
> smart signatures predicates, etc.
> We also have some cryptographic objects defined in CBOR that this group
> might find useful at
> https://github.com/BlockchainCommons/Research/blob/master/papers/bcr-2020-006-urtypes.md
> starting at 300.
> These are largely for airgap QR wallet oriented scenarios: request a seed,
> Shamir shard a seed, derive an hd-key, key, or address, join in a multisig
> account and sign your part of one (though the later two are Bitcoin-centric
> now they are designed to be adaptable in future), and animated QR for
> larger transfers.
> — Christopher Allen
Received on Monday, 14 February 2022 21:15:30 UTC

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