what is 'multi-hash'?

[gobengo]

added here by @TelegramSam merged @tplooker

• data: A JSON object that gives access to the actual content of the attachment. Contains the following subfields:
  ...
  • hash: The hash of the content encoded in multi-hash format. Optional. Used as an integrity check for the attachment, and > MUST be used if the data is referenced via the links data attribute.

What is 'multi-hash format' here? What should it hyperlink to as a specification and/or normative reference? 🙏

[gobengo]

Regardless of what to hyperlink to, does the reference generally refer to the same thing as what other DIF repos name 'multihash'?

i.e. https://multiformats.io/multihash/ - if so, you may want to keep an eye on this ietf multiformats list

[FabioPinheiro]

I also think this multihash reference to the multiformats https://multiformats.io/multihash/
Basically describes itself:

• the hash algorithm used
• the length of the hash that follows
• the real hash data

[rmlearney-digicatapult]

Any link to the CESR work? WebOfTrust/cesride#150 (comment)

[TelegramSam]

This spec predates a usable form of CESR. It has been posited that some future version may leverage CESR for encoding.

[TelegramSam]

We should add a link to the multi-hash spec. This is a clarification, and would not require a version change.

[gobengo]

A good link may be https://www.ietf.org/archive/id/draft-multiformats-multihash-07.html

See also this fledgling ietf wg https://datatracker.ietf.org/wg/multi/about/

[FabioPinheiro]

multi-hash is another draft spec that seems that is expired.

https://datatracker.ietf.org/doc/draft-multiformats-multihash/07/