Jun 23, 2025

Written by Nina Bongartz, Red Hat Trusted Artificat Signer Team

Trusting AI Models in Kubernetes: Introducing the Sigstore Model Validation Operator

As machine learning becomes deeply embedded in critical infrastructure, the question of trust in deployed models is increasingly critical. How can we be sure that an AI model running in a Kubernetes cluster is exactly what it claims to be? The OpenSSF AI/ML working group believes the answer can be found in signing AI models. A long-standing practice in traditional software distribution is to leverage cryptographic signatures to help end-users verify provenance: that software is authentic, has not been tampered with, and was authored by the expected creator.

Tags:  sigstore ,  artificial intelligence ,  model signing ,  machine learning ,  operator

Jun 6, 2025

Written by Zach Steindler (GitHub)

Sigstore & Post-Quantum Cryptography (2025)

In the coming years, systems will transition to post-quantum cryptographic algorithms (PQCA). There is some inherent tension in these transitions as we learn things through adoption, but making decisions too soon can saddle you with tech debt. The quick summary is that the Sigstore project wants to enable people to sign content with PQCA keys as soon as possible, and adopt PQCA in the Sigstore services (like Fulcio, Rekor, and a timestamp authority) when reliable and vetted PQCA is available in the Go ecosystem.

Tags:  sigstore ,  nist ,  postquantumcryptography

May 12, 2025

Written by Cody Soyland (GitHub)

sigstore-go 1.0 is now available

We love Go within the Sigstore community, and it’s been our language of choice since we got started. Cosign, Rekor, Fulcio, Policy Controller, and Timestamp Authority are all written in Go, and we’re lucky to have such a vibrant community of Go developers. Cosign was the de-facto Sigstore “client” from the beginning. Originally designed as a container image signing tool, it has become much more, introducing signing with ephemeral keys (with Fulcio), blob signing, attestation support, multi-cloud KMS support, and many more features.

Tags:  sigstore ,  go ,  clients

May 2, 2025

Written by Zach Steindler (GitHub)

Verifying Sigstore Bundles as an End User

There’s a mnemonic for quickly determining if a bicycle is safe to ride: “ABC” for checking the air in the tires, ensuring the brakes are functional, and checking the chain. It doesn’t definitively answer the question “is this bike safe?” but it does give you a quick starting point for your assessment. Let’s say you download some software and it comes with a Sigstore bundle. Similarly, there isn’t a quick, definitive answer to “is this software safe to use?

Tags:  sigstore ,  cosign ,  softwaresupplychain ,  security

Apr 17, 2025

Written by Hayden Blauzvern, Google

Rekor v2 - Cheaper to run, simpler to maintain

We are very excited to announce the alpha release of Rekor v2! Rekor v2 is a redesigned and modernized Rekor, Sigstore’s signature transparency log, transitioning its backend to a modern, tile-backed transparency log implementation to simplify maintenance and lower operational costs. Major changes include: A new storage backend, replacing Trillian with Trillian-Tessera. Tile-based logs are cheaper to run and easier to deploy, maintain and scale. To learn more about the benefits of tile-based logs, read this blog post A redesigned and simplified API, using the learnings from operating public-good Rekor over the past 2 years Stronger security guarantees that the log remains append-only by integrating witnessing directly into Rekor (To be implemented) For the initial release, we are providing a binary and container for developers.

Tags:  sigstore ,  rekor ,  transparency