CBOR-LD stabilization (was: Re: Regarding CBOR-LD Web Transports)

On 4/10/21 4:42 PM, Orie Steele wrote:
> I'm really enjoying working with CBOR-LD, even though it's still
> pretty young I think it holds tremendous promise, particularly
> because of its support for losses bi-directional transformations with
> JSON (LD).

Hey Orie, thanks for the shout out and for contributing Transmute's demo
to the growing body of work around CBOR-LD.

Digital Bazaar has a few updates to share with the community.

1. With a huge thank you to Dave Longley, a new version of the CBOR-LD
    library, with generalized and stable algorithms, and that works
    in the browser and node.js, has been released:
    https://github.com/digitalbazaar/cborld

2. We have split out the CBOR-LD command line interface into a
    separate project:
    https://github.com/digitalbazaar/cborld-cli/tree/initial

3. DB has released a CBOR-LD to QR Code image library for encoding
    and decoding Verifiable Presentations:
    https://github.com/digitalbazaar/vpqr

4. After some consultation with Mattr and Transmute, we've settled
    on a base32 alphanumeric QR Code encoding that is 10% more
    space efficient than base64url byte mode. This is important because
    this format is compatible with hundreds of QR Code readers on the
    market. Every QR Code reader that we've tested has worked with
    this new format.

At present, we can do a 1,107 byte digitally signed Age Verification
Token Verifiable Credential and compress it down to 357 bytes of
CBOR-LD, which translates to the following QR Code sizes (note: "matrix
size" can be thought of as "pixels wide x pixels high"):

base32 (error correction: high) -- Version: 21, matrix size: 101x101
base32 (error correction: medium) -- Version: 15, matrix size: 77x77
base32 (error correction: low) -- Version: 13, matrix size: 69x69

A sample QR Code encoded in this format is attached to this email. You
should be able to scan it with any Android or iOS QR Code scanner (the
camera app should work... the data should start with "VP1-", which means
"Verifiable Presentation Version 1").

At this point, adventurous implementers could take a look at the cborld
library code and implement their own version. We are fairly certain that
the code isn't going to change much at this point; we've hit a point of
stability and are interested to see if other implementers have feedback
on where we've landed with CBOR-LD.

We'll be providing more information in a few days on how this new
technology and these libraries are being deployed to address real use
cases in retail and healthcare.

-- manu

-- 
Manu Sporny (skype: msporny, twitter: manusporny)
Founder/CEO - Digital Bazaar, Inc.
blog: Veres One Decentralized Identifier Blockchain Launches
https://tinyurl.com/veres-one-launches