Rufus,

Google Trust Services does do CRL sharding but we DO NOT do individual CRLs 
per certificate. 

As an example, in the CRL you linked to in your post I count 329 entries 
(openssl crl -in fVJxbV-Ktmk.crl -inform DER -text|grep -c "Revocation 
Date").

I have not checked with the developers of the CA system on specifics for my 
response here so I am not sure there are not edge cases are but it seems 
likely that if there is only one revoked certificate from a CA you will 
sometimes see one entry CRLs. With that said our objective is to chunk 
entries them into useful, bite sized CRLs, not produce single CRLs per 
certificate.

With that background I would argue that modern day browser behavior of 
using delegated CRLs served by the browsers addresses the privacy concern 
in question. Specifically the concern as I understand it is that as a user 
visits a site with OCSP (which BTW can technically contain multiple CertIDs 
also) the URL (in the case of a GET request) of the revocation response 
leaks the site being browsed to. The reliance on these delegated CRLs 
served by browsers addresses this by removing the CA from the runtime 
interaction all together.

Ryan Hurst
Google Trust Services

On Monday, August 29, 2022 at 11:44:58 AM UTC-7 [email protected] 
wrote:

> Dear Ryan!
>
>  
>
> Thank you for sharing this information with us. Will this also have 
> influence on Google’s concept of individual crls per certificate (e.g. 
> http://crls.pki.goog/gts1c3/fVJxbV-Ktmk.crl for crt.sh | 7340166965 
> <https://crt.sh/?id=7340166965>)? I like this concept of extremely 
> sharded CRLs a lot since it effectively keeps the CRL size under control 
> but at the end it seems to me to have the same privacy issues as the OCSP 
> responder.
>
>  
>
> Greetings
>
>  
>
> Rufus
>
> IT IPS SIP ET
> Freyeslebenstr. 1
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>
>  
>
>  
>
> *From:* 'Ryan Dickson' via [email protected] <
> [email protected]> 
> *Sent:* Wednesday, 24 August 2022 14:14
> *To:* [email protected] <[email protected]>
> *Subject:* Revocation checking for EV server certificates in Chrome
>
>  
>
> Hello,
>
>  
>
> OCSP requests reveal details of individuals' browsing history to the 
> operator of the OCSP responder. These can be exposed accidentally (e.g., 
> via data breach of logs) or intentionally (e.g., via subpoena). This is 
> part of why Chrome doesn't do OCSP checks for Domain Validated (DV) or 
> Organization Validated (OV) certificates by default, and starting in 
> version 106, Chrome won't do them for Extended Validation (EV) certificates 
> either, to better protect users' privacy. 
>
>  
>
> Select revocation checking support will continue to be available through 
> CRLSets 
> <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.chromium.org%2FHome%2Fchromium-security%2Fcrlsets%2F&data=05%7C01%7Crufus.buschart%40siemens.com%7Ca61f65fe871f4bd8401808da85ca3035%7C38ae3bcd95794fd4addab42e1495d55a%7C1%7C0%7C637969400679584013%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rA1h5kn2kBXa52a09WFwUxtE1LHy3PKotnWsaJ6posI%3D&reserved=0>,
>  
> and OCSP stapling 
> <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FOCSP_stapling&data=05%7C01%7Crufus.buschart%40siemens.com%7Ca61f65fe871f4bd8401808da85ca3035%7C38ae3bcd95794fd4addab42e1495d55a%7C1%7C0%7C637969400679584013%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=sv3YhBhGbc%2B1%2B3Jj5Fiod7GLOA7gyrCDqDOmIuc%2BhIQ%3D&reserved=0>
>  
> will still be supported. Chrome also supports an enterprise policy 
> <https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fchromeenterprise.google%2Fpolicies%2F%23EnableOnlineRevocationChecks&data=05%7C01%7Crufus.buschart%40siemens.com%7Ca61f65fe871f4bd8401808da85ca3035%7C38ae3bcd95794fd4addab42e1495d55a%7C1%7C0%7C637969400679584013%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=MKPFgqs%2Fj%2B8nJ8RRUcpekzNT%2FObzC8%2FuzHPth1psHRs%3D&reserved=0>
>  
> to enable online revocation checking, though this may be removed in the 
> future. 
>
>  
>
> For any other questions or concerns, please email us at 
> [email protected].
>
>  
>
> Thanks,
>
> Ryan
>
> [Sent on behalf of the Chrome Root Program]
>
>  
>
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