[Multiformats] IETF 116 Dispatch Multiformats: Responses to Martin Dürst and Murray Kucherawy

[Manu Sporny <[e-mail]>]

Murray Kucherawy said:
> Does that example string decode into anything?

The example string in the slide deck that I believe you're referring
to is: uaGVsbG8gd29ybGQ

IETF 116: DISPATCH Multiformats Slide Deck:
https://docs.google.com/presentation/d/1WjKoxB-fxkPpaXB4kUu8IsTwQ4qXFmka1ocwEVEeBpk/edit#slide=id.g21fdb344882_0_206

Where the Multibase prefix 'u' indicates a base64url-no-pad encoding.
Stripping the 'u' value, and then feeding the rest (aGVsbG8gd29ybGQ)
into a base64url decoder, such as https://www.base64url.com/, gives
you the string: "hello world".

Martin Dürst said:
> For the "Hello World" example, can you express the charset?

The "hello world" example used during dispatch was expressed in
Multibase, which is an ASCII format. All other Multiformats are binary
formats, where some of the text-based formats express what charset to
use. For example, the Multicodec entry for "JSON" says that the data
is UTF-8 encoded).

There are no UTF-16 entries that I'm aware of, most likely because
Multiformats are rarely used to express string values. The
"plaintextv2" entry is missing a charset designation (which is likely
a registration error). One presumption we could make is that the
formats that carry the Multiformat value (such as CBOR, YAML, and
JSON) already have clear rules around charset  encoding OR, if
Multiformats are used as a byte header for a JSON or CBOR object, then
the corresponding format has clear charset rules that should be used.

That said, your concern is not entirely addressed. There is nothing in
the documentation around Multiformats that I have read to date that
gives a clear and definitive answer to your question.

> These questions need to be answered, not sure what alternative might be used for that.

Your charset question could be a signal that a mini-WG might be a
better option. When you asked your question, my internal dialogue was:
"Oh, that's interesting... why has that not come up in the
Multiformats community at all during the last 5+ years? And why is the
ecosystem able to operate w/o answering that question?". It might be
that I'm unaware of where that discussion happened, but I agree with
you, we should have a definitive answer.

-- manu

-- 
Manu Sporny - https://www.linkedin.com/in/manusporny/
Founder/CEO - Digital Bazaar, Inc.
https://www.digitalbazaar.com/