in-toto.

An open framework that cryptographically attests to every step of a software supply chain so that consumers can verify the artifact was built and handled exactly as the project owner intended. It belongs to the Application Security category of cybersecurity.

An open framework that cryptographically attests to every step of a software supply chain so that consumers can verify the artifact was built and handled exactly as the project owner intended.

in-toto, hosted by CNCF, models a software supply chain as a sequence of steps (e.g. clone, test, build, sign, publish) with declared inputs, outputs, and authorized actors. Each step produces a signed link metadata file recording materials and products; an overall layout authored by the project owner defines who must perform each step and how the artifacts flow between them. A verifier can take a final artifact and the corresponding attestations and check that the chain matches the policy. in-toto attestations are used to express SLSA provenance, vulnerability scan results, test pass evidence, and other signed predicates, often distributed via OCI registries and signed with Sigstore. It is a foundational technology for SLSA-aligned, verifiable supply chains.

Defences for in-toto typically combine technical controls and operational practices, as detailed in the full definition above.

Common alternative names include: in-toto, in-toto attestation.