PROPOSED RDF Dataset Canonicalization and Hash Working Group Charter

The mission of the RDF Dataset Canonicalization and Hash Working Group is to maintain the specifications previously published by this group. That work included a standard to uniquely and deterministically calculate a hash of RDF Datasets for use cases such as Detecting changes in Datasets, and was based on an RDF Dataset Canonicalization algorithm.

Join the RDF Dataset Canonicalization and Hash Working Group

This proposed charter is available on GitHub. Feel free to raise issues.

Charter Status See the group status page and detailed change history.
Start date [dd monthname yyyy] (date of the "Call for Participation", when the charter is approved)
End date [dd monthname yyyy] (Start date + 2 years)
Chairs Phil Archer, GS1
Markus Sabadello, Danube Tech
Team Contacts Pierre-Antoine Champin (0.05 FTE)
Meeting Schedule Teleconferences: topic-specific calls will be held on a per need basis.
Face-to-face: face-to-face meetings may be scheduled by consent of the participants, usually no more than 3 per year.

Motivation and Background

Various use cases depend on the ability to calculate a unique and deterministic hash value of RDF Datasets, such as Verifiable Credentials, the publication of biological and pharmaceutical data, and the consumption of mission critical RDF vocabularies that depend on the ability to verify the authenticity and integrity of the data being consumed. See the use cases for more examples. These use cases require the existence of a standard way to process the underlying graphs contained in RDF Datasets that is independent of the serialization itself.

Scope

The scope of this Working Group is to maintain the specifications published under the previous charter. That work included a standard to canonicalize and cryptographically hash an RDF Dataset, and was based on the definition of a standard canonicalization algorithm. (See the separate explainer document for more detailed technical background and for the terminology used in this context.)

See also some publications for RDF Dataset Canonicalization that served as inputs for the specification work:

  1. RDF Dataset Canonicalization, Rachel Arnold, Dave Longley, Report submitted to the W3C Credentials Community Group mailing list, 2020.
  2. Canonical Forms for Isomorphic and Equivalent RDF Graphs: Algorithms for Leaning and Labelling Blank Nodes, Aidan Hogan, ACM Trans. Web, vol. 11, no. 4, p. 22:1-22:62, 2017.
  3. A Framework for Iterative Signing of Graph Data on the Web, Andreas Kasten, Ansgar Scherp, Peter Schauß, European Semantic Web Conference — ESWC 2014, Springer Verlag, pp. 146-160, 2014.
  4. Signing RDF Graphs, Jeremy J. Carroll, International Semantic Web Conference — ISWC 2003, Springer Verlag, pp. 369-384, 2003.

Out of Scope

The following items are out of scope, and will not be addressed by this Working group.

  • Definition of new cryptographic hashing algorithms. This Working Group will only define the usage of algorithms such as, for example, BLAKE3 or SHA-3.
  • Definition of higher level protocols, like signature schemes, which is left to other groups.

Deliverables

Updated document status is available on the group publication status page.

Draft state indicates the state of the deliverable at the time of the charter approval. Expected completion indicates when the deliverable is projected to become a Recommendation, or otherwise reach a stable state

Normative Specifications

The Working Group will maintain the following W3C normative specifications:

RDF Dataset Canonicalization (rdf-canon)
Latest publication: 21 May 2024
Draft State: W3C Recommendation
Reference Draft: https://www.w3.org/TR/2024/REC-rdf-canon-20240521/
Associated Call for Exclusion 31 October 2023, ended on 30 December 2023
Produced under Working Group Charter: https://www.w3.org/2022/07/rch-wg-charter/

The Working Group may make class 4 changes to this specification, as it explicitly allows new features.

Other Deliverables

The Working Group will maintain the following W3C non-normative documents:

Test suite and implementation report
for the RDF Dataset Canonicalization specification
RDF Dataset Canonicalization and Hash Working Group — Explainer and Use Cases
Latest publication: 19 October 2023
Draft State: W3C Group Note
Reference Draft: https://www.w3.org/TR/2023/NOTE-rch-explainer-20231019/
Produced under Working Group Charter: https://www.w3.org/2022/07/rch-wg-charter/

The Working Group may create additional non-normative documents.

Success Criteria

In order to advance to Proposed Recommendation, each normative specification is expected to have at least two independent interoperable implementations of every feature defined in the specification, where interoperability can be verified by passing open test suites.

There should be testing plans for each specification, starting from the earliest drafts.

To promote interoperability, all changes made to specifications in Candidate Recommendation or to features that have deployed implementations should have tests.

Each specification should contain sections detailing all known security and privacy implications for implementers, Web authors, and end users.

This Working Group expects to follow the TAG Web Platform Design Principles.

Coordination

For all specifications, this Working Group will seek horizontal review for accessibility, internationalization, privacy, and security with the relevant Working and Interest Groups, and with the TAG. Invitation for review must be issued during each major standards-track document transition, including FPWD. The Working Group is encouraged to engage collaboratively with the horizontal review groups throughout development of each specification. The Working Group is advised to seek a review at least 3 months before first entering CR and is encouraged to proactively notify the horizontal review groups when major changes occur in a specification following a review.

Additional technical coordination with the following Groups will be made, per the W3C Process Document:

W3C Groups

Credentials Community Group
To coordinate on other specifications incubated and maintained by the Credentials Community Group at W3C.
Dataset Exchange Working Group
To synchronize on the needs and requirements of dataset publications and exchange regarding canonicalization.
RDF-star Working Group
To synchronize on the further evolution of the RDF Standard, such as canonicalization and hash functions for Generalized or RDF-star Graphs and Datasets.
Web Application Security Working Group
To ensure that the canonicalization and hashing mechanisms defined in this group have similar security properties to the rest of the Web, and to take advantage of lessons learned while designing other canonicalization systems.
Verifiable Credentials Working Group
To synchronize the definition and usage of the RDF Dataset Canonicalization and Hash, both needed for the ability to provide proofs for Verifiable Credentials.
Web of Things Working Group
To synchronize on the needs and requirements of the WoT community, in particular on the subject of WoT Thing Descriptions, regarding canonicalization.

External Organizations

Internet Engineering Task Force Crypto Forum Research Group
To perform broad horizontal reviews on the output of the Working Group and to ensure that new pairing-based and post-quantum cryptographic algorithms and parameters can be integrated into the RDF Dataset Hash ecosystem.
Hyperledger Aries
To coordinate on broad horizontal reviews and implementations related to the specifications developed by the Working Group.
Decentralized Identity Foundation Interoperability Working Group
To coordinate on broad horizontal review and integration of the specifications developed by the Working Group into the Decentralized Identity Foundation's ecosystem.

Participation

To be successful, this Working Group is expected to have 6 or more active participants for its duration, including representatives from the key implementors of this specification, and active Editors and Test Leads for each specification. The Chairs, specification Editors, and Test Leads are expected to contribute half of a working day per week towards the Working Group. There is no minimum requirement for other Participants.

The group encourages questions, comments and issues on its public mailing lists and document repositories, as described in Communication.

The group also welcomes non-Members to contribute technical submissions for consideration upon their agreement to the terms of the W3C Patent Policy.

Participants in the group are required (by the W3C Process) to follow the W3C Code of Conduct.

Communication

Technical discussions for this Working Group are conducted in public: the meeting minutes from teleconference and face-to-face meetings will be archived for public review, and technical discussions and issue tracking will be conducted in a manner that can be both read and written to by the general public. Working Drafts and Editor's Drafts of specifications will be developed in public repositories and may permit direct public contribution requests. The meetings themselves are not open to public participation, however.

Information about the group (including details about deliverables, issues, actions, status, participants, and meetings) will be available from the RDF Dataset Canonicalization and Hash Working Group home page.

Most RDF Dataset Canonicalization and Hash Working Group teleconferences will focus on discussion of particular specifications, and will be conducted on an as-needed basis.

This group primarily conducts its technical work on GitHub issues. The public is invited to review, discuss and contribute to this work.

The group may use a Member-confidential mailing list for administrative purposes and, at the discretion of the Chairs and members of the group, for member-only discussions in special cases when a participant requests such a discussion.

Decision Policy

This group will seek to make decisions through consensus and due process, per the W3C Process Document (section 5.2.1, Consensus). Typically, an editor or other participant makes an initial proposal, which is then refined in discussion with members of the group and other reviewers, and consensus emerges with little formal voting being required.

However, if a decision is necessary for timely progress and consensus is not achieved after careful consideration of the range of views presented, the Chairs may call for a group vote and record a decision along with any objections.

To afford asynchronous decisions and organizational deliberation, any resolution (including publication decisions) taken in a face-to-face meeting or teleconference will be considered provisional. A call for consensus (CfC) will be issued for all resolutions (for example, via email, GitHub issue or web-based survey), with a response period from 10 working days, depending on the chair's evaluation of the group consensus on the issue. If no objections are raised by the end of the response period, the resolution will be considered to have consensus as a resolution of the Working Group.

All decisions made by the group should be considered resolved unless and until new information becomes available or unless reopened at the discretion of the Chairs.

This charter is written in accordance with the W3C Process Document (Section 5.2.3, Deciding by Vote) and includes no voting procedures beyond what the Process Document requires.

Patent Policy

This Working Group operates under the W3C Patent Policy (Version of 15 September 2020). To promote the widest adoption of Web standards, W3C seeks to issue Web specifications that can be implemented, according to this policy, on a Royalty-Free basis. For more information about disclosure obligations for this group, please see the licensing information.

Licensing

This Working Group will use the W3C Software and Document license for all its deliverables.

About this Charter

This charter has been created according to section 3.4 of the Process Document. In the event of a conflict between this document or the provisions of any charter and the W3C Process, the W3C Process shall take precedence.

Charter History

The following table lists details of all changes from the initial charter, per the W3C Process Document (section 4.3, Advisory Committee Review of a Charter):

Charter Period Start Date End Date Changes
Initial Charter 21 July 2022 20 July 2024 -
Charter Extension 21 July 2022 20 November 2024 -
Maintenance WG Charter TBD Start date + 2 years Turn to maintenance mode