IETF Multiformats Working Group

Multiformats are a collection of self-describing data formats that consist of an inline data header and a data value. They are composable in that some of the more complex forms take another multiformat header/value tuple as value, recursively. Multiformats are designed to compose data into binary streams with both inline header values (called multicodecs) and corresponding data values, with the exception of multibase, which base-encodes any binary and prepends its inline header to the target encoding rather than to the binary data value being encoded.

The scope of this Working Group is to discuss these formats as they relate to standardization at the IETF for wider and safer usage. Specifically, the group is currently focused on the standardization of the two most generally-useful multiformats: multibase and multihash. The input documents for these two multiformats are:

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

Outputs for the group will be:

1. An RFC specifying multibase usage
2. An RFC defining an independent multibase registry and populating it with today's already-implemented stable and final values
3. An RFC defining a registry-group for all the multicodecs, empty at inception, with registration process and group-wide constraints on registration values
4. An RFC specifying multihash usage
5. An RFC defining a multihash registry within the multicodecs registry group and populating it with today's already-implemented stable and final values

The outputs from this Working Group are currently being used by various groups, including the W3C Verifiable Credentials Working Group, W3C Decentralized Identifiers Working Group, Conexxus Age Verification Working Group, W3C Dataset Canonicalization and Hashing Working Group, GS1 Verifiable Credentials, and online communities such as the W3C Credentials Community Group and Interplanetary File System developer community. The Multiformats Working Group will communicate progress and seek input and review from the Working Groups listed in this section as well as other relevant groups as the work progresses.

Items that are out of scope for the group include:

• Standardizing other multiformats that are not explicitly listed in the charter.
• Creating or standardizing new data formats identified by a multicodec byte header.
• Determining whether one data format is better than another data format.
• Changing current multiformat header assignments in a way that breaks backward compatibility with production deployments.