IPng Networks

Certificate Transparency

ctlog logo

Certificate Transparency logs are “append-only” and publicly-auditable ledgers of certificates being created, updated, and expired. This is the homepage for IPng Networks’ Certificate Transparency project.

Certificate Transparency [CT] is a system for logging and monitoring certificate issuance. It greatly enhances everyone’s ability to monitor and study certificate issuance, and these capabilities have led to numerous improvements to the CA ecosystem and Web security. As a result, it is rapidly becoming critical Internet infrastructure. Originally developed by Google, the concept is now being adopted by many Certification Authories who log their certificates, and professional Monitoring companies who observe the certificates and report anomalies.

IPng Networks runs our logs under the domain ct.ipng.ch, split into a *.log.ct.ipng.ch for the write-path, and *.mon.ct.ipng.ch for the read-path.

We are submitting our log for inclusion in the approved log lists for Google Chrome and Apple Safari. Following 90 days of successful monitoring, we anticipate our log will be added to these trusted lists and that change will propagate to people’s browsers with subsequent browser version releases.

We operate two popular implementations of Static Certificate Transparency software.

Sunlight

[Sunlight] was designed by Filippo Valsorda for the needs of the WebPKI community, through the feedback of many of its members, and in particular of the Sigsum, Google TrustFabric, and ISRG teams. It is partially based on the Go Checksum Database. Sunlight’s development was sponsored by Let’s Encrypt.

Our Sunlight logs:

  • A staging log called [Rennet], incepted 2025-07-28, starting from temporal shard rennet2025h2.
  • A production log called [Gouda], incepted 2025-07-30, starting from temporal shard gouda2025h2.

TesseraCT

[TesseraCT] is a Certificate Transparency (CT) log implementation by the TrustFabric team at Google. It was built to allow log operators to run production static-ct-api CT logs starting with temporal shards covering 2026 onwards, as the successor to Trillian’s CTFE.

Our TesseraCT logs:

  • A staging log called Lipase.
  • A production log called Halloumi.

Operational Details

You can read more details about our infrastructure on:

  • [TesseraCT], published on 2025-07-26.
  • Sunlight (todo)
  • Operational Notes (todo)

The operators of this infrastructure are Antonis Chariton, Jeroen Massar and Pim van Pelt.
You can reach us via e-mail at [ct-ops@ipng.ch].