Known Logs

This page contains details of the currently known CT Logs.

The list of CT logs that are currently compliant with Chrome's CT policy (or have been and were disqualified) is available in a machine-readable (JSON) format at:
log_list.json is signed by Google, the signature being hosted at:
The public key to verify log_list.sig can be found at:
The list of CT all known and announced logs is available in a machine-readable (JSON) format at:
Both log_list.json and all_logs_list.json conform with the following schema:

Included in Chrome


ct.googleapis.com/icarus

Base64 Log ID: KTxRllTIOWW6qlD8WAfUt2+/WHopctykwwz05UVH9Hg=
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/632753

ct.googleapis.com/pilot

Base64 Log ID: pLkJkLQYWBSHuxOizGdwCjw1mAT5G9+443fNDsgN3BA=
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/389511

ct.googleapis.com/rocketeer

Base64 Log ID: 7ku9t3XOYLrhQmkfq+GeZqMPfl+wctiDAMR7iXqo/cs=
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/431057

ct.googleapis.com/skydiver

Base64 Log ID: u9nfvB+KcbWTlCOXqpJ7RzhXlQqrUugakJZkNo4e0YU=
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/632752

ct.startssl.com

Base64 Log ID: NLtq1sPfnAPuqKSZ/3iRSGydXlysktAfe/0bzhnbSO8=
Operator: StartCom
Contact: ct@startssl.com
Chrome bug: https://crbug.com/611672

ct.ws.symantec.com

Base64 Log ID: 3esdK3oNT6Ygi4GtgWhwfi6OnQHVXIiNPRHEzbbsvsw=
Operator: Symantec
Contact: DL-ENG-Symantec-CT-Log@symantec.com
Chrome bug: https://crbug.com/483625

ct1.digicert-ct.com/log

Base64 Log ID: VhQGmi/XwuzT9eG9RLI+x0Z2ubyZEVzA75SYVdaJ0N0=
Operator: DigiCert
Contact: ctops@digicert.com
Chrome bug: https://crbug.com/419255

ct2.digicert-ct.com/log

Base64 Log ID: h3W/51l8+IxDmV+9827/Vo1HVjb/SrVgwbTq/16ggw8=
Operator: DigiCert
Contact: ctops@digicert.com
Chrome bug: https://crbug.com/698094
Included in Chrome since M-60

ctlog-gen2.api.venafi.com

Base64 Log ID: AwGd8/2FppqOvR+sxtqbpz5Gl3T+d/V5/FoIuDKMHWs=
Operator: Venafi
Contact: ctlog-admin@venafi.com
Chrome bug: https://crbug.com/688510

ctlog.wosign.com

Base64 Log ID: QbLcLonmPOSvG6e7Kb9oxt7m+fHMBH4w3/rjs7olkmM=
Operator: WoSign
Contact: ctlog@wosign.com
Chrome bug: https://crbug.com/605415
Included in Chrome since M-54

ctserver.cnnic.cn

Base64 Log ID: pXesnO11SN2PAltnokEInfhuD0duwgPC7L7bGF8oJjg=
Operator: CNNIC
Contact: ctlog-admin@cnnic.cn
Chrome bug: https://crbug.com/583208

mammoth.ct.comodo.com

Base64 Log ID: b1N2rDHwMRnYmQCkURX/dxUcEdkCwQApBo2yCJo32RM=
Operator: Comodo
Contact: ctops@comodo.com
Contact: rob.stradling@comodo.com
Chrome bug: https://crbug.com/703699
Included in Chrome since M-60

sabre.ct.comodo.com

Base64 Log ID: VYHUwhaQNgFK6gubVzxT8MDkOHhwJQgXL6OqHQcT0ww=
Operator: Comodo
Contact: ctops@comodo.com
Contact: rob.stradling@comodo.com
Chrome bug: https://crbug.com/703700
Included in Chrome since M-60

sirius.ws.symantec.com

Base64 Log ID: FZcEiNe5l6Bb61JRKt7o0ui0oxZSZBIan6v71fha2T8=
Operator: Symantec
Contact: DL-ENG-Symantec-SIRIUS-CT-Log@symantec.com
Chrome bug: https://crbug.com/692782
Included in Chrome since M-60

vega.ws.symantec.com

Base64 Log ID: vHjh38X2PGhGSTNNoQ+hXwl5aSAJwIG08/aRfz7ZuKU=
Operator: Symantec
Contact: DL-ENG-Symantec-VEGA-CT-Log@symantec.com
Chrome bug: https://crbug.com/554549


Frozen Logs


ct.googleapis.com/aviator

Base64 Log ID: aPaY+B9kgr46jO65KB1M/HFRXWeT1ETRCmesu09P+8Q=
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/389514


Pending Inclusion in Chrome


ct.googleapis.com/logs/argon2017

Base64 Log ID: +tTJfMSe4vishcXqXOoJ0CINu/TknGtQZi/4aPhrjCg=
Certificate Expiry Range: [2017-01-01 00:00:00 UTC, 2018-01-01 00:00:00 UTC)
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/756813

ct.googleapis.com/logs/argon2018

Base64 Log ID: pFASaQVaFVReYhGrN7wQP2KuVXakXksXFEU+GyIQaiU=
Certificate Expiry Range: [2018-01-01 00:00:00 UTC, 2019-01-01 00:00:00 UTC)
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/756814

ct.googleapis.com/logs/argon2019

Base64 Log ID: Y/Lbzeg7zCzPC3KEJ1drM6SNYXePvXWmOLHHaFRL2I0=
Certificate Expiry Range: [2019-01-01 00:00:00 UTC, 2020-01-01 00:00:00 UTC)
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/756817

ct.googleapis.com/logs/argon2020

Base64 Log ID: sh4FzIuizYogTodm+Su5iiUgZ2va+nDnsklTLe+LkF4=
Certificate Expiry Range: [2020-01-01 00:00:00 UTC, 2021-01-01 00:00:00 UTC)
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/756818

ct.googleapis.com/logs/argon2021

Base64 Log ID: 9lyUL9F3MCIUVBgIMJRWjuNNExkzv98MLyALzE7xZOM=
Certificate Expiry Range: [2021-01-01 00:00:00 UTC, 2022-01-01 00:00:00 UTC)
Operator: Google
Contact: google-ct-logs@googlegroups.com
Chrome bug: https://crbug.com/756819

ct.cloudflare.com/logs/nimbus2017

Base64 Log ID: H7w24ALt6X9AGZ6Gs1c7ikIX2AGHdGrQ2gOgYFTSDfQ=
Certificate Expiry Range: [2017-01-01 00:00:00 UTC, 2018-01-01 00:00:00 UTC)
Operator: Cloudflare
Contact: ct-logs@cloudflare.com
Contact: brendan@cloudflare.com
Contact: nick@cloudflare.com
Contact: pat@cloudflare.com
Contact: zi@cloudflare.com
Contact: ivan@cloudflare.com
Chrome bug: https://crbug.com/780653

ct.cloudflare.com/logs/nimbus2018

Base64 Log ID: 23Sv7ssp7LH+yj5xbSzluaq7NveEcYPHXZ1PN7Yfv2Q=
Certificate Expiry Range: [2018-01-01 00:00:00 UTC, 2019-01-01 00:00:00 UTC)
Operator: Cloudflare
Contact: ct-logs@cloudflare.com
Contact: brendan@cloudflare.com
Contact: nick@cloudflare.com
Contact: pat@cloudflare.com
Contact: zi@cloudflare.com
Contact: ivan@cloudflare.com
Chrome bug: https://crbug.com/780654

ct.cloudflare.com/logs/nimbus2019

Base64 Log ID: dH7agzGtMxCRIZzOJU9CcMK//V5CIAjGNzV55hB7zFY=
Certificate Expiry Range: [2019-01-01 00:00:00 UTC, 2020-01-01 00:00:00 UTC)
Operator: Cloudflare
Contact: ct-logs@cloudflare.com
Contact: brendan@cloudflare.com
Contact: nick@cloudflare.com
Contact: pat@cloudflare.com
Contact: zi@cloudflare.com
Contact: ivan@cloudflare.com
Chrome bug: https://crbug.com/780655

ct.cloudflare.com/logs/nimbus2020

Base64 Log ID: Xqdz+d9WwOe1Nkh90EngMnqRmgyEoRIShBh1loFxRVg=
Certificate Expiry Range: [2020-01-01 00:00:00 UTC, 2021-01-01 00:00:00 UTC)
Operator: Cloudflare
Contact: ct-logs@cloudflare.com
Contact: brendan@cloudflare.com
Contact: nick@cloudflare.com
Contact: pat@cloudflare.com
Contact: zi@cloudflare.com
Contact: ivan@cloudflare.com
Chrome bug: https://crbug.com/780656

ct.cloudflare.com/logs/nimbus2021

Base64 Log ID: RJRlLrDuzq/EQAfYqP4owNrmgr7YyzG1P9MzlrW2gag=
Certificate Expiry Range: [2021-01-01 00:00:00 UTC, 2022-01-01 00:00:00 UTC)
Operator: Cloudflare
Contact: ct-logs@cloudflare.com
Contact: brendan@cloudflare.com
Contact: nick@cloudflare.com
Contact: pat@cloudflare.com
Contact: zi@cloudflare.com
Contact: ivan@cloudflare.com
Chrome bug: https://crbug.com/780657

ct.sheca.com

Base64 Log ID: MtxZwtTEGWjVbhS8YayPDkXbOfrzwVWqQlL1AB+gxiM=
Operator: SHECA
Contact: CTLS@sheca.com
Chrome bug: http://crbug.com/712069


Disqualified from Chrome


ct.izenpe.com

Base64 Log ID: dGG0oJz7PUHXUVlXWy52SaRFqNJ3CbDMVkpkgrfrQaM=
Operator: Izenpe
Contact: atecnica@izenpe.net
Chrome bug: https://crbug.com/431700

ctlog.api.venafi.com

Base64 Log ID: rDua7X+pZ0dXFZ5tfVdWcvnZgQCUHpve/+yhMTt1eC0=
Operator: Venafi
Contact: ctlog-admin@venafi.com
Chrome bug: https://crbug.com/499446

log.certly.io

Base64 Log ID: zbUXm3/BwEb+6jETaj+PAC5hgvr4iW/syLL1tatgSQA=
Operator: Certly
Contact: ian@certly.io
Chrome bug: https://crbug.com/442173


Rejected by Chrome


alpha.ctlogs.org

Base64 Log ID: OTdvVF97Rgf1l0LXaM1dJDe/NHO2U0pINLz3Lmgcg8k=
Operator: Matt Palmer
Contact: ops@ctlogs.org
Chrome bug: http://crbug.com/403190

ct.akamai.com

Base64 Log ID: lgbALGkAM6odFF9ZxuJkjQVJ8N+WqrjbkVpw2OzzkKU=
Operator: Akamai
Contact: ct-help@akamai.com
Chrome bug: http://crbug.com/447603

ct.gdca.com.cn

Base64 Log ID: yc+JCiEQnGZswXo+0GXJMNDgE1qf66ha8UIQuAckIao=
Operator: Wang Shengnan
Contact: capoc@gdca.com.cn
Chrome bug: https://crbug.com/598526

ct.izenpe.eus

Base64 Log ID: iUFEnHB0Lga5/JznsRa6ACSqNtWa9E8CBEBPAPfqhWY=
Operator: Izenpe
Contact: atecnica@izenpe.eus
Chrome bug: https://crbug.com/614323

ct.wosign.com

Base64 Log ID: nk/3PcPOIgtpIXyJnkaAdqv414Y21cz8haMadWKLqIs=
Operator: WoSign
Contact: ctlog@wosign.com
Chrome bug: https://crbug.com/534745

ctlog.gdca.com.cn

Base64 Log ID: kkow+Qkzb/Q11pk6EKx1osZBco5/wtZZrmGI/61AzgE=
Operator: GDCA
Contact: capoc@gdca.com.cn
Chrome bug: https://crbug.com/654306

ctlog.sheca.com

Base64 Log ID: z1XiiSNJfDQNUgbQU1Ouslg0tS8fjclSaAnyEu/dfKY=
Operator: SHECA
Contact: CTLS@sheca.com
Chrome bug: http://crbug.com/704033

ctlog2.wosign.com

Base64 Log ID: Y9AAYCbd4QuwYB9FJEaWXuK26izU+8layGalUK+Qdbc=
Operator: WoSign
Contact: ctlog@wosign.com
Chrome bug: https://crbug.com/717826


Completely Distrusted by Chrome


www.certificatetransparency.cn/ct

Base64 Log ID: 4BJ2KekEllZOPQFHmESYqkj4rbFmAOt5AqHvmQmQYnM=
Operator: Beijing PuChuangSiDa Technology Ltd.
Contact: certificatetransparency@outlook.com
Chrome bug: https://crbug.com/667663
Included in Chrome since M-58
Removed from Chrome since M-60


Other Logs


ct.googleapis.com/daedalus

Base64 Log ID: HQJLjrFJizRN/YfqPvwJlvdQbyNdHUlwYaR3PEOcJfs=
Operator: Google
Contact: google-ct-logs@googlegroups.com

Note that this log is not trusted by Chrome. It only logs certificates that have expired. See the announcement post.

ct.googleapis.com/submariner

Base64 Log ID: qJnYeAySkKr0YvMYgMz71SRR6XDQ+/WR73Ww2ZtkVoE=
Operator: Google
Contact: google-ct-logs@googlegroups.com

Note that this log is not trusted by Chrome. It only logs certificates that chain to roots that are on track for inclusion in browser roots or were trusted at some previous point. See the announcement blog post.

ct.googleapis.com/testtube

Base64 Log ID: sMyD5aX5fWuvfAnMKEkEhyrH6IsTLGNQt8b9JuFsbHc=
Operator: Google
Contact: google-ct-logs@googlegroups.com

Note that this log is intended for testing purposes only and will only log certificates that chain to a root explicitly added to it.
To add a test root to Testtube, please email google-ct-logs@googlegroups.com

A test root for Testtube should:
  • have a certificate "Subject" field that:
    • includes the word "Test" (to reduce the chances of real certificates being mixed up with test certificates.
    • identifies the organization that the test root is for (to allow easy classification of test traffic).
  • not allow real certificates to chain to it, either because:
    • it is a self-signed root CA certificate identified as a test certificate (as above).
    • it is an intermediate CA certificate that chains to a root certificate that is also identified as a test certificate.
  • be a CA certificate, by:
    • having CA:TRUE in the Basic Constraints extension.
    • include the 'Certificate Sign' bit in the Key Usage extension.
Note that for historical reasons Testtube includes some test roots that do not comply with all of the above requirements.

clicky.ct.letsencrypt.org

Base64 Log ID: KWr6LVaLyg0uqESVaulyH8Nfo1Xs2plpOq/UWKca790=
Operator: Let's Encrypt
Contact: roland@letsencrypt.org

ct.filippo.io/behindthesofa

Base64 Log ID: sLeEvIHA3cR1ROiD8FmFu5B30TTYq4iysuUzmAuOUIs=
Operator: Up In The Air Consulting
Contact: filippo@cloudflare.com

deneb.ws.symantec.com

Base64 Log ID: p85KTmIH4K3e5f2qSx+GdodntdACpV1HMQ5+ZwqV6rI=
Operator: Symantec

dodo.ct.comodo.com

Base64 Log ID: 23b9raxl59CVCIhuIVm9i5A1L1/q0+PcXiLrNQrMe5g=
Operator: Comodo
Contact: ctops@comodo.com
Contact: rob.stradling@comodo.com

flimsy.ct.nordu.net:8080

Base64 Log ID: U3tpo1ZDNanASQTjlZOywpjrjXpugwI2NcYnJIzWtEA=
Operator: NORDUnet
Contact: linus@nordu.net

plausible.ct.nordu.net

Base64 Log ID: qucLfzy41WbIbC8Wl5yfRF9pqw60U1WJsvd6AwEE880=
Operator: NORDUnet
Contact: linus@nordu.net


Comments