

Ask HN: Why do Chrome and Firefox only support SHA1 for cipher suites? - DiabloD3

I want to shut off all crypto methods that are a security issue on my company&#x27;s web server. We use nginx.<p>We have a 4096 bit RSA key, signed with SHA256, use a 4096 bit dhparam, have only TLS 1.0[1] and up enabled, and use !3DES:!AES128:!aNULL:!eNULL:FIPS@STRENGTH for our ssl ciphers.<p>See the ssltest output for my site to see what various browsers do (scroll down to Handshake Simulation): https:&#x2F;&#x2F;www.ssllabs.com&#x2F;ssltest&#x2F;analyze.html?d=exelion.net<p>Why does current Chrome and current Firefox only support SHA? If I do !SHA in ssl ciphers, no browser can connect due to lack of compatible cipher.<p>Now, scroll back up to Cipher Suites. I support cipher suites with SHA256 and SHA384, clearly. So what gives? Why doesn&#x27;t Chrome and Firefox allow those? And if you look closely, they still don&#x27;t do GCM either.<p>[1]: It took Android browser until 4.4 to support TLS 1.2, Firefox 24 ESR doesn&#x27;t do 1.2, all the web spider bots don&#x27;t do TLS 1.2, MSIE 10 and lower don&#x27;t do 1.2, Safari 6 on OSX and Safari 5 on iOS don&#x27;t do 1.2.<p>Android browser in 4.0-4.3 being unable to do 1.2 is the only reason I still leave 1.0 enabled.
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valarauca1
Qualys SSL Labs fails to load the link you give me reason, "No secure ciphers
supported." Which I think is a bug because I've gotten that twice today.

When a browser and web server agree on a cipher suite its not necessarily the
most 'secure', just the first they agree on.

This is largely controlled by the client. Who basically iterates over their
list (from lowest to smallest).

Do you have 0x002F? (128bit AES DHE).

No.

And you continue to count upwards. By the time you reach more powerful suites
that use SHA256/386 (~0x0080-0x0090) you've paste SHA-1 w/ AES256 using Diffe-
Hellman exchange, and SHA-1 w/ RC4 using Diffe-Hellman. The two most common
(and one is arguably secure) suites used (RC4 makes up a good 40% of all TLS
traffic).

Your only real option I think is to black list SHA-1 crypto which _may_ cause
issues.

<pure speculation>

Smart phones may disable SHA-256+ methods because of extra computing power
needed.

</pure speculation>

~~~
DiabloD3
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