Draft:International Standard Content Code

• Comment: Sources do not support the text. E.g. source 13, https://iscc.codes/concept
  does not support base32. The CODE and UNIT composition is also not directly mentioned. ChrysGalley (talk) 19:44, 9 February 2026 (UTC)

• Comment: In accordance with the Wikimedia Foundation's Terms of Use, I disclose that I have been paid by my employer for my contributions to this article. Correction: this disclosure was added automatically by the Article Wizard in error. I am not paid to edit Wikipedia. I do have a conflict of interest as an unpaid board member of the ISCC Foundation, which is separately disclosed on my user page and on the talk page per WP:COI. Etma 1222 (talk) 11:12, 23 April 2026 (UTC)

• Comment: Notability basis: independent significant coverage in NISO/Carpenter (2024), the joint IEC-ISO-ITU AMAS technical report (2025), and the peer-reviewed Fraunhofer paper in Electronic Imaging (2025). The subject also meets WP:NSTANDARD as a published ISO standard (ISO 24138:2024) that has been adopted nationally as AS/NZS ISO 24138:2025. Etma 1222 (talk) 10:42, 4 June 2026 (UTC)

International Standard Content Code (ISCC)
Abbreviation	ISCC
Status	Published
Year started	2016
First published	15 May 2024
Latest version	ISO 24138:2024
Organization	ISO/TC 46/SC 9
Domain	Digital media content identification
Website	iscc.io

The International Standard Content Code (ISCC) is a similarity-preserving identifier for digital media assets such as text, images, audio, and video, standardized as ISO 24138:2024. An ISCC is computed from a file rather than assigned by a registration authority, so any party holding the same file can derive the same code. Because an ISCC is derived from the content, it differs from registry-assigned identifiers such as the ISBN or DOI, which are assigned by an authority; the fingerprint it produces also remains largely stable after a work is edited or re-encoded. An ISCC combines several code units. Each unit is derived from one aspect of a file: its metadata, its perceptual features, its raw byte sequence, or a cryptographic hash of its contents. Because similar files yield similar codes, an ISCC can be used to detect near-duplicates and match content across formats and encodings. The standard was published in 2024 after development within ISO/TC 46/SC 9. Since then the ISCC has been incorporated into the ONIX book-trade metadata standard and added to the C2PA list of soft-binding algorithms, and it has been used in rights-management and AI-governance settings. Its open-source reference implementation is maintained by the ISCC Foundation.

History

Development

The ISCC was created by Titusz Pan (ORCID 0000-0002-0521-4214), an open-source developer working on content identification and the inventor of the ISCC. According to the ISCC Foundation, Pan was the principal editor of ISO 24138:2024. Pan developed the first ideas for the ISCC in early 2016; later that year the work was taken up by the Content Blockchain Project, a consortium that studied blockchain technology for journalism and digital media and received funding from the Google Digital News Initiative. The project published an early specification and a prototype, and released an open-source ISCC 1.0 specification and reference code in 2018. In 2019 the project received one of Germany's inaugural Digital Publishing Awards at the Leipzig Book Fair.

Standardization

In 2019 the International Organization for Standardization took up the ISCC as a work item within Technical Committee 46, Subcommittee 9 (TC 46/SC 9, Identification and description). A dedicated working group, WG 18, was established to develop it and held its first meeting on 29 October 2019. The committee reviewed the draft through the usual ISO ballot stages, including a draft international standard (DIS) review in 2023. ISO 24138:2024 was published on 15 May 2024. It defines the syntax, structure, and algorithms for generating ISCC codes and describes their use alongside existing identifier schemes such as DOI, ISAN, ISBN, ISRC, ISSN, and ISWC. The standard includes a reference implementation, published as a freely available electronic insert under its normative Annex D, "Reference implementation". In 2025 the standard was adopted nationally in Australia and New Zealand as AS/NZS ISO 24138:2025.

Industry adoption

In July 2020 the ISCC was added to ONIX, the international book-trade metadata standard maintained by EDItEUR, allowing an ISCC to be carried alongside the ISBN in book-trade metadata. In May 2024 the Coalition for Content Provenance and Authenticity (C2PA) added the ISCC to its list of approved soft binding algorithms, registered as io.iscc.v0 with an entry date of 17 May 2024. Most other entries on the list are digital watermarking schemes. A soft binding algorithm re-associates a content-provenance manifest with a file after the file's embedded metadata has been removed. In 2025 a joint technical report by the IEC, ISO, and ITU, prepared through the AI and Multimedia Authenticity Standards (AMAS) collaboration, reviewed standards for AI-generated and altered media. The report listed the ISCC among asset-identifier standards.

Structure

An ISCC-CODE is a composite of several ISCC-UNITs, each computed from a different aspect of the content.

Units

The standard defines the following unit types:

• Meta-Code: a similarity hash (SimHash) of basic metadata, typically the name and an optional description, used to cluster assets with similar descriptive information.
• Semantic-Code: reserved as a code type in ISO 24138, with its algorithm not yet specified in the standard. Experimental implementations use deep learning embeddings of the semantic content of text and images.
• Content-Code: a modality-specific perceptual fingerprint:
  • Text: a MinHash over normalized character n-grams.
  • Image: a discrete cosine transform-based perceptual hash.
  • Audio: a Chromaprint-based fingerprint condensed with SimHash.
  • Video: MPEG-7 frame signatures summed across frames and condensed with a Winner-Take-All hash.
• Data-Code: a similarity-preserving hash of the raw file bytes, using content-defined chunking and MinHash.
• Instance-Code: a BLAKE3 cryptographic hash of the file, used for exact integrity verification.

A unit can stand alone or be combined into an ISCC-CODE. Unit bodies are sized in 32-bit steps, from 32 up to 256 bits, with a default of 64 bits. When units are combined into an ISCC-CODE, each body is truncated to 64 bits before they are concatenated. A minimum ISCC-CODE contains the Data-Code and the Instance-Code; the other units are optional and precede them in canonical order.

Format

Each ISCC-UNIT begins with a variable-length header, commonly two bytes, that encodes the unit's main type, subtype, version, and length, followed by a variable-length body holding the fingerprint data. The units are concatenated and encoded in Base32 (RFC 4648, without padding) for the canonical string form, prefixed with ISCC:. A representative ISCC-CODE that combines Meta-Code, text Content-Code, Data-Code, and Instance-Code units is:

ISCC:KACT4EBWK27737D2AYCJRAL5Z36G76RFRMO4554RU26HZ4ORJGIVHDI

Similarity preservation

Unlike a cryptographic hash, which changes completely after any edit, an ISCC-UNIT changes only partially: similar inputs produce similar codes, and the Hamming distance between two units approximates the similarity of the underlying content. Applications use this to detect near-duplicates and to cluster related content by comparing codes.

Comparison with other identifiers

Comparison of the ISCC with registry-assigned identifiers

Identifier	Scope	Assignment	Similarity detection
ISBN	Book editions	Assigned by national agencies	No
DOI	Scholarly works	Assigned by registration agencies	No
ISRC	Sound recordings	Assigned by national agencies	No
ISWC	Musical compositions	Assigned via collecting societies	No
ISCC	Digital media files	Computed from content	Yes

Traditional identifiers are assigned by registration authorities and identify abstract works or specific editions. The ISCC identifies the digital file, so a single book edition with one ISBN can correspond to many ISCCs, one per format, compression level, or excerpt. ISO 24138 specifies the ISCC for use alongside DOI, ISAN, ISBN, ISRC, ISSN, and ISWC rather than as a replacement. A 2026 European Union Intellectual Property Office (EUIPO) study mapping EU copyright databases and metadata standards discussed the ISCC among the content-identification schemes it surveyed.

Applications

Documented and proposed uses of the ISCC include:

• Detecting exact and near-duplicate content for deduplication and database synchronization.
• Verifying file integrity through the Instance-Code.
• Tracking versions of the same underlying content.
• Identifying AI-generated content and recording text and data mining (TDM) opt-out declarations under the EU AI Act. In a 2025 Electronic Imaging paper, researchers at the Fraunhofer Institute for Secure Information Technology proposed using the ISCC as a robust hashing method within an infrastructure for tagging AI-generated content. In a January 2026 submission to a European Commission consultation, the International Federation of Reproduction Rights Organisations suggested the ISCC as a possible basis for machine-readable TDM rights reservations.
• Research data management. The ELIXIR Galaxy platform integrated the ISCC for content-based reproducibility validation and dataset deduplication in bioimage analysis workflows.

Use in cultural heritage

In a 2024 blog post, staff at the TIB and the Berlin State Library argued that libraries, archives, and museums should adopt the ISCC, citing content authentication, comparison of similar works, and registration of machine-learning training data.

CommonsDB

CommonsDB is a European Commission-funded pilot registry of rights information for public domain and openly licensed works that uses the ISCC as its content-derived identifier. A user can check the rights status of a file by generating its ISCC and looking up matching declarations. By March 2026 the registry contained over one million rights declarations.

Reception

In the scholarly-publishing and standards communities, the ISCC has been described as an example of "intrinsic" identifiers. A 2024 report on the PIDfest 2024 conference, co-authored by the chair of ISO/TC 46/SC 9, named the ISCC as one example of such intrinsic identifier systems. Writing a guest column in Music Ally, Virginie Berger pointed to the ISCC as an existing ISO-standard fingerprinting method that the music industry could use for content traceability.

Implementation

The open-source reference implementation of ISO 24138 is maintained by the ISCC Foundation on GitHub. The core repositories are:

Core ISCC reference repositories

Repository	Description
iscc-core	Reference implementation of the ISO 24138 algorithms
iscc-sdk	High-level Python SDK for ISCC generation
iscc-schema	JSON Schema definitions and metadata models
iscc-web	REST API service powering the public demonstration

The Foundation also publishes experimental generators for semantic codes (iscc-sct for text and iscc-sci for images) and iscc-lib, a Rust implementation of the core algorithms with bindings for several languages. Independent implementations include iscc-core-ts, a TypeScript port, and iscc-sum, a Rust tool that generates the Data-Code and Instance-Code.

ISCC Foundation

The ISCC Foundation (Stichting ISCC) is a nonprofit foundation (stichting) under Dutch law, founded in Leiden in May 2019 and based in Hengelo, Netherlands. According to the Foundation, its activities include research on content identification, participation in open-standards work, maintenance of the open-source reference implementation, and support for community adoption.

See also

• Content ID
• Perceptual hashing
• Content Authenticity Initiative
• International Standard Audiovisual Number
• Cryptographic hash function

External links

• Official website
• ISCC open specifications (IEPs)

This page will be placed in the following categories if it is moved to the article namespace.

Categories:

• Identifiers
• ISO standards
• Open standards
• Metadata
• Digital media