Add Q2 2026 Sigstore updates

TI-reports/2026/2026-Q2-Sigstore.md

@@ -0,0 +1,53 @@
+# 2026 Q2 Sigstore
+
+## Post-quantum cryptographic readiness
+
+Following the community's [timeline and plan](https://docs.google.com/document/d/15wQW5RCk55_CrIOYEtzJ0IyazbBGdMK8KsaI8S8oJ7U/edit?pli=1&tab=t.0#heading=h.o3tezvh8snap)
+to create and rollout infrastructure and clients that support post-quantum cryptographic signatures, we have now
+authored a [design document](https://docs.google.com/document/d/1g3WQk4JSwQ26MGwB-Kkhu8ylrPF5JnE4v62d2tDC2xY/edit)
+(please join [sigstore-dev](https://groups.google.com/g/sigstore-dev) to view)
+with technical details on the infrastructure and client changes. We're excited
+to get started and will have much to demo in the coming months. We welcome
+any community feedback, particularly from those with private Sigstore deployments
+to better understand their operational requirements.
+
+## Adoption highlights
+
+* [Pixi](https://pixi.prefix.dev/latest/) is leveraging sigstore-rust to create attestations
+* [mise](https://github.com/jdx/mise) is using sigstore-rust to verify GitHub artifact attestations
+
+## Rekor v2 as the default paused
+
+Given our focus has shifted to supporting PQC, we will not pursue making Rekor v2
+the default log, as this would be a breaking change for ecosystems. The public instance
+will still remain up, clients just won't write to it by default.
+
+We have an upcoming [blog post](https://github.com/sigstore/sigstore-blog/pull/95)
+with more details, including how to use Rekor v2 and benefits to clients that do
+choose to switch over.
+
+## Cosign v3.1
+
+[Cosign v3.1](https://github.com/sigstore/cosign/releases/tag/v3.1.0) was recently released,
+which deprecates a significant number of flags as we continue our efforts around signature
+standardization with the [Bundle](https://blog.sigstore.dev/cosign-verify-end-user/) format.
+
+Cosign v4, which will remove all deprecated flags, will follow shortly. Clients can stay on
+v3.x if needed.
+
+## OpenSSF TI-funded log monitoring website
+
+[Through OSSF TI funding](https://github.com/ossf/tac/issues/536), work continues to
+build a website for monitoring the Rekor transparency log, akin to https://www.gopherwatch.org/.
+See an early version [here](https://github.com/trailofbits/rekor-watch), which will be merged
+into [sigstore/rekor-monitor](https://github.com/sigstore/rekor-monitor) shortly. We will
+work with the broader community to identify an organization to stand up an instance of the monitor.
+
+## Funding requests and updates
+
+We are not planning any additional funding requests at this time.
+
+Updates for existing funding requests:
+
+* [Log monitoring website](https://github.com/ossf/tac/issues/536) - Funds have been fully allocated with monthly invoicing, work is wrapping up
+* [Rust client audit](https://github.com/ossf/tac/issues/574) - Trail of Bits will be completing this audit starting early Q3.