Sigstore
What is Sigstore?
SigstoreAn open-source Linux Foundation project that makes signing, verifying, and protecting software artifacts easy by combining short-lived keys, OIDC identities, and a transparency log.
Sigstore is a set of cooperating services - Cosign for signing artifacts, Fulcio as a free OIDC-based certificate authority issuing short-lived signing certificates, and Rekor as a public, append-only transparency log of signatures. Developers authenticate with their existing identity provider (GitHub, Google, etc.) and Fulcio issues a brief signing certificate; Cosign signs containers, binaries, SBOMs, or in-toto attestations and records the signature in Rekor. Verification fetches the log entry and checks the identity and signature without long-lived private keys to manage. Sigstore is widely used in OCI container ecosystems, package registries, and SLSA-aligned pipelines to defend against supply-chain attacks.
● Examples
- 01
Signing container images in CI with Cosign and verifying them at Kubernetes admission.
- 02
Publishing signed SBOMs and in-toto attestations to Rekor for public verification.
● Frequently asked questions
What is Sigstore?
An open-source Linux Foundation project that makes signing, verifying, and protecting software artifacts easy by combining short-lived keys, OIDC identities, and a transparency log. It belongs to the Application Security category of cybersecurity.
What does Sigstore mean?
An open-source Linux Foundation project that makes signing, verifying, and protecting software artifacts easy by combining short-lived keys, OIDC identities, and a transparency log.
How does Sigstore work?
Sigstore is a set of cooperating services - Cosign for signing artifacts, Fulcio as a free OIDC-based certificate authority issuing short-lived signing certificates, and Rekor as a public, append-only transparency log of signatures. Developers authenticate with their existing identity provider (GitHub, Google, etc.) and Fulcio issues a brief signing certificate; Cosign signs containers, binaries, SBOMs, or in-toto attestations and records the signature in Rekor. Verification fetches the log entry and checks the identity and signature without long-lived private keys to manage. Sigstore is widely used in OCI container ecosystems, package registries, and SLSA-aligned pipelines to defend against supply-chain attacks.
How do you defend against Sigstore?
Defences for Sigstore typically combine technical controls and operational practices, as detailed in the full definition above.
What are other names for Sigstore?
Common alternative names include: sigstore.
● Related terms
- appsec№ 226
Cosign
An open-source CLI from the Sigstore project for signing, verifying, and attesting to OCI artifacts and other software using either keyed or keyless workflows.
- appsec№ 522
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.
- appsec№ 1053
SLSA Framework
Supply-chain Levels for Software Artifacts: a tiered set of requirements published by OpenSSF that progressively hardens how software is built, signed, and verified against supply-chain tampering.
- appsec№ 1069
Software Supply Chain Security
The discipline of protecting every link of the software production chain - source, dependencies, build, signing, distribution, and deployment - against tampering, malicious code, and integrity loss.
- appsec№ 784
Package Signing
Applying a cryptographic signature to a software package so that consumers can verify the publisher's identity and that the artifact has not been altered after release.
- appsec№ 870
Provenance Attestation
A signed, machine-verifiable statement that describes how a software artifact was produced - including source, build system, parameters, and dependencies - so consumers can trust its origin.