[Feature]: Support deterministic encoding (or DAG-CBOR)

[TheButlah]

Is there an existing issue for this?

• I have searched the existing issues

Description

one of the goals of DAG-CBOR (a more strict version of CBOR) is that data should be deterministic in its encoding and decoding, such that data round trips identically. It would be good for ciborium to implement this guarantee of determinism/round tripping via some attribute on structs or maybe in the encode/decode functions. I think its broadly useful, even outside of DAG-CBOR

See also here and here

Acceptance Criteria

Passing tests with conformance against at least section 4.2 of RFC8949 and, if willing, additional tests to cover any additional strictness imposed by DAG-CBOR.

Suggestions for a technical implementation

See also https://github.com/ipld/serde_ipld_dagcbor

[cyberphone]

Here is another take on deterministically encoded CBOR:
Live: https://cyberphone.github.io/CBOR.js/doc/playground.html
Specification: https://datatracker.ietf.org/doc/draft-rundgren-cbor-core/

I would love to have a Rust implementation but my Rust-skills are zero and I don't know if Ciborium would be a good starting point.

One of the major drivers include the introduction of Embedded Signatures.