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How can they efficiently do that? Will they send a request to Google/Mozilla/Firefox and asks if cert ABC logged? I see two issues with that: 1) the browser v
by Matt3o12_ 9y ago
How can they efficiently do that? Will they send a request to Google/Mozilla/Firefox and asks if cert ABC logged?
I see two issues with that:
1) the browser vendors know each site and subdomain I visit. This seems to be a privacy issue.
2) every new visits adds a lot of latency because they need to check the certificate every time I request a site (now it becomes: dns, ssl handshake, cert check, http transfer).
3) when the cert check server is down, what is supposed to happen? Fail every ssl request? This adds a new point of failure. Just allow it? An attacked could black-hole the dns or block the IP address.
- y0ghur7_xxx 9y ago> How can they efficiently do that? The web server sends a Signed Certificate Timestamp in the TLS Handshake¹. The browser will check that. Apache support is coming², and other web server vendors are probably working on it as well. ¹https://tools.ietf.org/html/rfc6962#page-13 https://tools.ietf.org/html/rfc6962#page-13 ²https://httpd.apache.org/docs/trunk/mod/mod_ssl_ct.html https://httpd.apache.org/docs/trunk/mod/mod_ssl_ct.html
- prdonahue 9y agoEven better is embedding the SCTs in the x509 structure itself so that you don't have to rely on obtaining/caching and the sending in the handshake. (Yes, there's some cases where a policy change my require the addition of additional SCTs—or different ones altogether—but this should be the exception not the norm.)
- schoen 9y agoSee "SCT" in https://www.certificate-transparency.org/how-ct-works https://www.certificate-transparency.org/how-ct-works
- the8472 9y agoSimilar to OCSP stapling the server could also include CT publication attestations.