How can I access the certificate transparency logs?

Question

Am I going crazy or is there no way to access any of the "known logs" listed on Google's Certificate Transparency site? Every single one of the links listed there 404s, even though the list is allegedly up to date. Is there some arcane way of accessing them that everyone is already supposed to know? The website says nothing about how to go about it.

I did find this library, which seems to provide some sort of interface with a log, but it appears to be using regular HTTPS in order to access them, just as a browser or curl would (to my understanding), which is what is 404ing for me. Am I missing something here or is every single link in the Known Logs list really dead?

(And yes, I posted this question on their forums but no one has answered.)

EDIT: I'm looking for a way to access them via an API, not through a human-computer interface like a web form.

Answer 1

You can get the base URLs of known CT log providers from http://www.certificate-transparency.org/known-logs, however if you try to access that base URL, you'll just get a 404, instead you need to access it with the correct paths and parameters instead of the root endpoint.

For example, given the base URL of Xenon2023 log which is listed in that page as https://ct.googleapis.com/logs/xenon2023/, you can access the STH (signed tree head) with the URL: https://ct.googleapis.com/logs/xenon2023/ct/v1/get-sth

Or to access log entries numbered 1000 to 1100: https://ct.googleapis.com/logs/xenon2023/ct/v1/get-entries?start=1000&end=1100

RFC 6962 describes all the paths and parameters used for CT operations, or you can use a library like https://github.com/google/certificate-transparency.

Answer 2

Is this what you're looking for?

Google Transparency Report

It gives you the ability to search the CT logs for all certs issued to a particular domain.

Answer 3

If you do interested in programmatic accessing CT logs then one possible way forward could be the lib I made CTjs. There you could find an an example how to use it - it is example using all possible APIs and features of CT log. Also there is RFC6962 example on a real data from all known CT logs.