Chromium Certificate Transparency Policy

This repository contains documents related Chromium's Certificate Transparency policies, such as the Certificate Transparency Log Policy.

Their contents can be discussed in the ct-policy@chromium.org forum.

For Certificate Authorities

In order to help protect users of the Chromium Projects, CAs are expected to support Certificate Transparency. This allows users, the Chromium Authors, and the public to verifiably audit that CAs are conforming to the policies set out in Chromium's Root Certificate Policy.

Chromium requires all publicly-trusted TLS certificates issued after April 30, 2018 to support CT as described in the Certificate Transparency in Chrome Policy. Extended Validation (EV) TLS certificates issued before this date are also required to support CT in order to be recognized as an EV certificate in Chromium.

For Log Operators

In order for a Log to be included within Chromium, it must meet the requirements of the Certificate Transparency Log Policy. The Log Policy describes the steps for Log Operators to submit Logs for inclusion within Chromium.

Recognized Logs

The following table includes information about the Certificate Transparency Logs that are recognized by Chromium. It includes information about who operates the log, the name the log has been given, and the URL that can be used for logging certificates or inspecting the certificates that have been logged.

Note: The authoritative list is maintained in the Chromium code base. This is merely informational.

Qualified Logs

Log Operator	Log Name	Log URL	MMD	Qualified In	Current State
Google	Google 'Aviator' Log	https://ct.googleapis.com/aviator	24 hours	Chrome 35	Read Only
Google	Google 'Pilot' Log	https://ct.googleapis.com/pilot/	24 hours	Chrome 35	Usable
DigiCert	DigiCert's Certificate Transparency log	https://ct1.digicert-ct.com/log/	24 hours	Chrome 41	Usable
Google	Google 'Rocketeer' Log	https://ct.googleapis.com/rocketeer	24 hours	Chrome 43	Usable
Google	Google 'Icarus' Log	https://ct.googleapis.com/icarus/	24 hours	Chrome 55	Usable
Google	Google 'Skydiver' Log	https://ct.googleapis.com/skydiver/	24 hours	Chrome 55	Usable
Venafi	Venafi Gen2 CT log	https://ctlog-gen2.api.venafi.com/	24 hours	Chrome 59	Read Only
DigiCert	DigiCert Log Server 2	https://ct2.digicert-ct.com/log/	24 hours	Chrome 60	Usable
Sectigo	Sectigo 'Mammoth' Log	https://mammoth.ct.comodo.com/	24 hours	Chrome 60	Usable
Sectigo	Sectigo 'Sabre' Log	https://sabre.ct.comodo.com/	24 hours	Chrome 60	Usable
Cloudflare	Cloudflare 'Nimbus2019' Log	https://ct.cloudflare.com/logs/nimbus2019/	24 hours	Chrome 65	Usable
Cloudflare	Cloudflare 'Nimbus2020' Log	https://ct.cloudflare.com/logs/nimbus2020/	24 hours	Chrome 65	Usable
Cloudflare	Cloudflare 'Nimbus2021' Log	https://ct.cloudflare.com/logs/nimbus2021/	24 hours	Chrome 65	Usable
Google	Google 'Argon2019' Log	https://ct.googleapis.com/logs/argon2019/	24 hours	Chrome 65	Usable
Google	Google 'Argon2020' Log	https://ct.googleapis.com/logs/argon2020/	24 hours	Chrome 65	Usable
Google	Google 'Argon2021' Log	https://ct.googleapis.com/logs/argon2021/	24 hours	Chrome 65	Usable
DigiCert	DigiCert 'Yeti2019' Log	https://yeti2019.ct.digicert.com/log/	24 hours	Chrome 67	Usable
DigiCert	DigiCert 'Yeti2020' Log	https://yeti2020.ct.digicert.com/log/	24 hours	Chrome 67	Usable
DigiCert	DigiCert 'Yeti2021' Log	https://yeti2021.ct.digicert.com/log/	24 hours	Chrome 67	Usable
DigiCert	DigiCert 'Yeti2022' Log	https://yeti2022.ct.digicert.com/log/	24 hours	Chrome 67	Usable
DigiCert	DigiCert 'Nessie2019' Log	https://nessie2019.ct.digicert.com/log/	24 hours	Chrome 72	Usable
DigiCert	DigiCert 'Nessie2020' Log	https://nessie2020.ct.digicert.com/log/	24 hours	Chrome 72	Usable
DigiCert	DigiCert 'Nessie2021' Log	https://nessie2021.ct.digicert.com/log/	24 hours	Chrome 72	Usable
DigiCert	DigiCert 'Nessie2022' Log	https://nessie2022.ct.digicert.com/log/	24 hours	Chrome 72	Usable
Google	Google 'Xenon2019' Log	https://ct.googleapis.com/logs/xenon2019/	24 hours	Chrome 73	Usable
Google	Google 'Xenon2020' Log	https://ct.googleapis.com/logs/xenon2020/	24 hours	Chrome 73	Usable
Google	Google 'Xenon2021' Log	https://ct.googleapis.com/logs/xenon2021/	24 hours	Chrome 73	Usable
Google	Google 'Xenon2022' Log	https://ct.googleapis.com/logs/xenon2022/	24 hours	Chrome 73	Usable
Cloudflare	Cloudflare 'Nimbus2022' Log	https://ct.cloudflare.com/logs/nimbus2022/	24 hours	Chrome 76	Qualified
Cloudflare	Cloudflare 'Nimbus2023' Log	https://ct.cloudflare.com/logs/nimbus2023/	24 hours	Chrome 76	Qualified
DigiCert	DigiCert 'Nessie2023' Log	https://nessie2023.ct.digicert.com/log/	24 hours	Chrome 76	Qualified
DigiCert	DigiCert 'Yeti2023' Log	https://yeti2023.ct.digicert.com/log/	24 hours	Chrome 76	Qualified
Google	Google 'Xenon2023' Log	https://ct.googleapis.com/logs/xenon2023/	24 hours	Chrome 77	Qualified
Google	Google 'Argon2022' Log	https://ct.googleapis.com/logs/argon2022/	24 hours	Chrome 77	Qualified
Google	Google 'Argon2023' Log	https://ct.googleapis.com/logs/argon2023/	24 hours	Chrome 77	Qualified

Once, but no longer, Qualified Logs

Log Operator	Name	Log URL	MMD	Qualified In	Last Accepted SCT
Certly	Certly.IO Log	https://log.certly.io	24 hours	Chrome 43	15 April 2016 00:00:00 UTC.
Izenpe	Izenpe Log	https://ct.izenpe.com	24 hours	Chrome 44	30 May 2016 00:00:00 UTC.
Venafi	Venafi CT Log Server	https://ctlog.api.venafi.com/ct/v1	24 hours	Chrome 47	28 Feb 2017 18:42:26 UTC.
WoSign	WoSign Log	https://ctlog.wosign.com/	24 hours	Chrome 54	12 Feb 2018 23:59:59 UTC.
StartCom	StartCom CT Log	https://ct.startssl.com/	24 hours	Chrome 54	12 Feb 2018 23:59:59 UTC.
CNNIC	CNNIC CT Log	https://ctserver.cnnic.cn/	24 hours	Chrome 53	18 Sep 2018 00:00:00 UTC.
DigiCert	Symantec Log	https://ct.ws.symantec.com	24 hours	Chrome 45	16 Feb 2019 00:00:00 UTC.
DigiCert	Symantec 'Vega' Log	https://vega.ws.symantec.com/	24 hours	Chrome 50	16 Feb 2019 00:00:00 UTC.
DigiCert	Symantec 'Sirius' Log	https://sirius.ws.symantec.com/	24 hours	Chrome 60	16 Feb 2019 00:00:00 UTC.
Google	Google 'Argon2018' Log	https://ct.googleapis.com/logs/argon2018/	24 hours	Chrome 65	Rejected - Shard Expired
Cloudflare	Cloudflare 'Nimbus2018' Log	https://ct.cloudflare.com/logs/nimbus2018/	24 hours	Chrome 65	Rejected - Shard Expired
DigiCert	DigiCert 'Yeti2018' Log	https://yeti2018.ct.digicert.com/log/	24 hours	Chrome 67	Rejected - Shard Expired
DigiCert	DigiCert 'Nessie2018' Log	https://nessie2018.ct.digicert.com/log/	24 hours	Chrome 72	Rejected - Shard Expired

Policy Version

Chromium Certificate Transparency Policy Version 1.0