Quoting 2017_TLS_Telemetry_Report.pdf:

Not surprisingly, 2048-bit keys now protect 90% of the world’s TLS hosts. The use of 4096-bit keys have quadrupled, as a share of hosts, but we expect it to start shrinking again as Elliptic Curve Digital Signature Algorithm (ECDSA) gains favor.

That report was issued in 2017 however and I can find no newer report.

My question is... is there a more recent report that has more up-to-date stats?

  • Your title says X.509 and you also tagged TLS, but that F5 report is only for HTTPS on a subset of the public net (web). Is that what you want? HTTPS is only a subset of TLS, there is private HTTPS and other TLS in addition to public, and there is much other X.509 usage in addition to TLS, but the public net and public web is the easiest to observe.And do you care about the key in the cert (i.e. the subject's key, used for TLS, and an RSA key can be used in TLS<=1.2 for either encryption or signature) or the signature on the cert, which can be and sometimes is a different algorithm? – dave_thompson_085 Jun 26 '19 at 3:19
  • "Is that what you want?" I'll take whatever I can get. I'm just trying to get a feel for what the most popular public key algorithms are. If there was a way to poll SSH servers to see what key types were in their authorized_keys files I'd be interested in seeing that but the SSH protocol does not allow that. – neubert Jun 26 '19 at 3:40
  • "do you care about the key in the cert" good catch. I updated my post to more accurately reflect what I want. I suppose I could analyze curl.haxx.se/docs/caextract.html but idk that CAs are necessarily representative of the average X509 cert. Most CA's just have you submit a CSR with a public key and they just sign it, thereby producing an X509 cert. So I feel a report like the F5 one would be a more accurate representation of the landscape. – neubert Jun 26 '19 at 3:42

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