CAC Ontology

Watch the overview

A short video introduction to what CAC Ontology is and how it helps people model and exchange investigation knowledge.

Latest release: v3.1.0

CAC Ontology v3.1.0 expands investigation modeling while pinning interoperability to CASE/UCO 1.5.0 and gUFO 1.0.0. Highlights include the spine-level Conditioning macro-phase, CaseLinker exploitation-lifecycle extensions, richer legal-outcomes modeling, structured NCMEC aggregate-report statistics, and attribution / victim-vulnerability concepts.

Project VIC International is building its Technology Ecosystem on this open semantic foundation — including VICTrace and AI-assisted modeling through the CASE/UCO SDK and its MCP server.

Express & Exchange

The Crimes Against Children (CAC) Ontology Family is a community-developed evolving standard that provides a structured (ontology-based) specification for representing information commonly analyzed and exchanged by people and systems during investigations involving digital evidence related to crimes against children.

The power of CAC Ontology is that it provides a common language to support automated normalization, combination and validation of varied information sources to facilitate analysis and exploration of investigative questions (who, when, how long, where). In addition to representing tool results, CAC Ontology ensures that analysis results can be traced back to their source(s), keeping track of when, where and who used which tools to perform investigative actions on data sources.

CAC Ontology extends the Unified Cyber Ontology (UCO), the Cyber-investigation Analysis Standard Expression (CASE) Ontology (currently pinned to CASE/UCO 1.5.0), and the Unified Foundational Ontology (gUFO). This powerful combination provides specialized modules for modeling child exploitation investigations, operations, legal processes, reporting, offender tradecraft, and digital forensics activities with high semantic precision.

CAC Ontology is part of the Linux Foundation Cyber Domain Ontology ecosystem, which provides a shared foundation for interoperable cyber-investigation information exchange.

CAC Ontology is language encoded

Think of CAC Ontology as a way to write the language we already use as a connected graph.

• Namespaces: topic-specific vocabularies (a “subdomain of language”)
• Classes: the concepts you want to talk about
• Properties: how concepts are described and connected
• SHACL: business rules that validate the “grammar” of your data

About the Initiative

The CAC Ontology is shepherded by Project VIC International, but further development of this initiative is open to any participant. The CAC Ontology represents many of the concepts used in spoken and written language globally by government and law enforcement agencies, NGOs, academic organizations, and commercial industry.

Our plan is to continue to evolve this family of ontologies to represent new victim-centric language as it is developed and used across the world. We view the CAC Ontology as a semantic foundation that AI technologies can build upon.

We understand that not all language is represented, so we ask persons and organizations to provide concepts, documents, and data that we can reference to improve the CAC Ontology.