ISO/IEC 18670:2025

Information technology - SoftWare Hash IDentifier (SWHID) Specification V1.2

This specification defines a standard data format for referencing software artifacts that match the data model of modern distributed version control systems.

This format includes the typical tree-like structure of a filesystem hierarchy, but also, special nodes to track revisions and releases, as well as the full status of a version control system, with all its development branches.

A key property of SWHIDs is that they can be computed using cryptographically strong functions directly from the digital objects they refer to, by anyone that has access to a copy of those objects. This enables decentralised and independent verification of integrity, without relying on a registry or a central authority.

The computation of the SWHID identifiers is based on Merkle Acyclic Directed Graphs, a natural generalization of Merkle trees.

The resolution of SWHIDs, that is, the process of obtaining a copy of a digital artifact corresponding to a given SWHID, is outside the scope of this specification.