Sigstore is an open source project that helps software creators and consumers sign and verify artifacts such as release files, container images, binaries and SBOMs. Its signing keys are ephemeral, so nobody has to protect a long-lived key, and every signing event goes into a public log anyone can audit.
The three parts
Sigstore is a small set of cooperating tools:
- Cosign is the client. It creates a key pair, requests a certificate, and signs the artifact.
- Fulcio is the certificate authority. It checks the signer's OpenID Connect identity token and issues a short-lived certificate tied to that identity and public key.
- Rekor is a transparency log, an append-only ledger that records the artifact's digest, signature and certificate.
Why short-lived keys help
Traditional signing relies on a private key that must live somewhere safe for years. If it leaks, the attacker can sign as you. With Sigstore the certificate is tied to an identity and expires quickly, so there is no long-lived secret to steal from a build server.
The trade is that verification becomes about identity: "was this signed by the account or workflow I expect?" You need to decide which identities you trust.
What verification checks
Per the project, a verifier confirms four things: the signature on the artifact, that the certificate's identity matches the expected signer, that the certificate chains to Sigstore's root of trust, and that an entry exists in Rekor. The log lets identity owners watch how their identity is used and lets downloaders confirm the certificate was valid at signing time.
A signature is not a safety certificate
Signing proves who produced an artifact and that it was not changed afterward. It does not prove the artifact is free of malicious code. A compromised but legitimate publisher can sign something harmful. Treat signing as one layer, next to build provenance and dependency scanning.
Getting started
- Sign your container images and release binaries in CI.
- Publish the expected signer identity so consumers know what to verify against.
- Add a verification step to deployment, and fail closed when it does not pass.
- Sign your SBOMs too, so the inventory cannot be swapped.
Safeguard enforces policies and gates on pipelines and scans dependencies. A free scan is at gold.safeguard.sh/scan.
Quick check
Do I have to manage signing keys with Sigstore?
The project describes the keys as ephemeral, so you do not maintain long-lived signing keys.
Does a valid signature mean the software is safe?
No. It shows who signed and that the artifact is unchanged. It does not judge what the code does.
Sources
Last reviewed: 19 October 2026.
