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I have been attempting to configure my site to have http/2 support, but I kept having to remove cipher suites because of the blacklist. Eventually, I got the list whittled down sufficiently.

The problem, however, is that I only have a cipher suite compatible with TLS 1.2 now. I'd love to use this, but it's not practical as it breaks Safari versions as new as shipping with OS X 10.10 because those only support CBC suites.

Any thoughts as to what to do to have reasonable compatibility, yet support HTTP/2?

Presently, the list is AESGCM+EECDH:AESGCM+EDH:!SHA1:!DSS:!DSA:!ECDSA:!aNULL

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    There is no special cipher suite needed for HTTP/2 but your server but support the HTTP/2 protocol. See wiki.mozilla.org/Security/… for useful configuration examples regarding ciphers. Mar 20, 2016 at 7:25
  • @SteffenUllrich Yes, but there's a giant blacklist that makes the page not load in compliant browsers. This has very minimal overlap with the pre-tls 1.2 suites. Mar 20, 2016 at 15:59
  • You need an overlap of a single cipher suite between client and server. It is not a problem if the server offers lots of (secure) cipher suites so that it can pick one which is offered by the client. The server can also support ciphers which are not offered by the client. Don't restrict yourself unnecessarily at the server side. Mar 20, 2016 at 16:47
  • @SteffenUllrich I realised I misread the spec. It doesn't prohibit offering insecure ciphers... it just doesn't allow negotiation of one. So, basically, I need to find the least insecure one supported by clients. Mar 20, 2016 at 22:06
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    For any future visitors: See RFC 9113 section 9.2.2. TLS 1.2 Cipher Suites, httpwg.org/specs/rfc9113.html#tls12ciphers which references Appendix A, a list of unallowed cipher suites: httpwg.org/specs/rfc9113.html#BadCipherSuites
    – Moshe
    Jul 18, 2023 at 17:56

2 Answers 2

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Have a look to the list of suites (and the order) supported by https://www.shimmercat.com , I'm pretty sure the site works in Mac OX X and iOS. You can use qualys SSL tools to get the list.

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The most widely used and accepted cipher specification, or cipher suite set designed for HTTP/2 was originally provided by the industry leading CDN and web giant CloudFlare who posted the SSL cipher and protocol setup from their nginx conf:

ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers EECDH+CHACHA20:EECDH+AES128:RSA+AES128:EECDH+AES256:RSA+AES256:EECDH+3DES:RSA+3DES:!MD5;
ssl_prefer_server_ciphers on;

From What-cipher-suites-does-CloudFlare-use-for-SSL I have seen this referenced in multiple locations as a good starting point, or a default set designed for HTTP/2 which is then tweaked to your servers/clients needs. Right away many may choose not to support TLS 1.0 any longer due to the BEAST attack vulnerability.

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    I believe AES_128 are mandatory to have for HTTP/2 support. Am i correct?
    – Dzintars
    Aug 14, 2019 at 16:33

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