Introduction

Certificate Transparency is a system for monitoring and auditing publicly-trusted SSL certificates. This website monitors Certificate Transparency log servers to check that they are behaving correctly.

Logs

Show:

Log URL Newest verified STH timestamp (UTC) Status Uptime
Akamai https://ct.akamai.com 2015-07-27 17:28:48 Ceased N/A
Behind The Sofa https://ct.filippo.io/behindthesofa 2017-07-23 22:09:00 Warning 99.87%
Certly https://log.certly.io 2016-04-30 17:59:42 Ceased N/A
CNNIC https://ctserver.cnnic.cn 2017-07-24 02:02:41 Good 99.77%
Comodo Dodo https://dodo.ct.comodo.com 2017-07-24 02:21:39 Warning 99.86%
Comodo Mammoth https://mammoth.ct.comodo.com 2017-07-24 02:22:09 Good 99.92%
Comodo Sabre https://sabre.ct.comodo.com 2017-07-24 02:21:42 Good 99.97%
DigiCert 1 https://ct1.digicert-ct.com/log 2017-07-23 14:00:50 Good 99.91%
DigiCert 2 https://ct2.digicert-ct.com/log 2017-07-23 14:00:56 Good 99.92%
GDCA https://ctlog.gdca.com.cn 2017-07-24 02:22:12 Warning 99.43%
GDCA (Legacy) https://ct.gdca.com.cn 2017-07-24 02:14:46 Warning 99.75%
Google Aviator https://ct.googleapis.com/aviator 2016-11-30 13:24:18 Frozen 99.95%
Google Daedalus https://ct.googleapis.com/daedalus 2017-07-24 01:42:25 Good 99.97%
Google Icarus https://ct.googleapis.com/icarus 2017-07-24 01:05:58 Good 99.95%
Google Pilot https://ct.googleapis.com/pilot 2017-07-23 23:03:36 Good 99.96%
Google Rocketeer https://ct.googleapis.com/rocketeer 2017-07-24 00:00:36 Good 99.95%
Google Skydiver https://ct.googleapis.com/skydiver 2017-07-24 01:21:41 Good 99.97%
Google Submariner https://ct.googleapis.com/submariner 2017-07-24 01:16:27 Good 99.95%
Google Test Tube https://ct.googleapis.com/testtube 2017-07-24 02:04:57 Good 99.96%
Izenpe https://ct.izenpe.com 2016-10-25 07:25:56 Ceased N/A
Izenpe Argi https://ct.izenpe.eus 2017-06-05 09:53:01 Ceased N/A
Izenpe Pilot https://ct.izenpe.com/pilot 2016-05-14 19:41:49 Ceased N/A
Let's Encrypt Clicky https://clicky.ct.letsencrypt.org 2017-06-02 07:58:06 Ceased N/A
NORDUnet Flimsy https://flimsy.ct.nordu.net N/A Ceased N/A
NORDUnet Plausible https://plausible.ct.nordu.net 2017-07-24 02:16:24 Warning 97.05%
PuChuangSiDa https://www.certificatetransparency.cn/ct 2017-05-12 02:40:17 Ceased N/A
SHECA https://ct.sheca.com 2017-07-24 02:19:15 Good 98.52%
SHECA (Legacy) http://ctlog.sheca.com 2017-03-23 09:47:08 Ceased N/A
SSLWatcher.com Alpha https://alpha.ctlogs.org N/A Ceased N/A
StartCom https://ct.startssl.com 2017-07-24 02:17:24 Good 99.48%
Symantec https://ct.ws.symantec.com 2017-07-24 01:00:17 Good 99.93%
Symantec Deneb https://deneb.ws.symantec.com 2017-07-24 01:00:00 Good 99.81%
Symantec Sirius https://sirius.ws.symantec.com 2017-07-24 01:00:00 Good 99.93%
Symantec Vega https://vega.ws.symantec.com 2017-07-24 01:00:00 Good 99.93%
Venafi https://ctlog.api.venafi.com 2017-07-24 01:06:14 Warning 99.89%
Venafi Gen2 https://ctlog-gen2.api.venafi.com 2017-07-24 01:48:48 Warning 99.76%
WoSign https://ctlog.wosign.com 2017-07-24 02:15:14 Good 99.43%
WoSign 2 https://ctlog2.wosign.com 2017-07-24 01:59:26 Good 99.69%
WoSign 3 https://ctlog3.wosign.com 2017-07-24 02:19:12 Good 99.10%
WoSign (Legacy) https://ct.wosign.com 2016-04-14 03:22:46 Ceased N/A

The list of logs is also available in JSON format at /logs.json. The schema is identical to the schema used by the official log_list.json and all_logs_list.json files, with the following exceptions:

Monitors

Gossip is exchanged with the following monitors:

Monitor URL
Cert Spotter https://certspotter.com
Chromium STHSets https://clients2.google.com/service/update2/crx
ct.x509.io https://ct.x509.io

Signed Tree Head gossip

Two API endpoints are provided for exchanging STH gossip:

Both return all the STHs observed over the last hour, so there is little point in querying them more than once every 30 minutes. If you use one of these endpoints, I'd appreciate being able to fetch gossip from your monitor in return. In particular, the /ct/v1/sth-gossip endpoint doesn't support exchanging gossip in both directions. Get in touch with me if you want to organise this.

Tor

This website is also available as a Tor hidden service at ctgpe47oofn4ov5v.onion if you want to exchange gossip while remaining anonymous.

Methodology

I've put up a page describing the methodology used by the monitor. If the monitor displays a warning or bad status for a log, you should read the methodology page before reporting it to the log operator (or even better, get in touch, as the web interface doesn't present all of the available data). In particular, the backend is hosted from a residential Internet connection and network outages may cause false positives.