Re: alpn + ciphers

Ilari Liusvaara <ilariliusvaara@welho.com> Fri, 16 October 2015 13:08 UTC

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From: Ilari Liusvaara <ilariliusvaara@welho.com>
To: Stefan Eissing <stefan.eissing@greenbytes.de>
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Subject: Re: alpn + ciphers
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On Fri, Oct 16, 2015 at 01:28:27PM +0200, Stefan Eissing wrote:
> 
> During ALPN callbacks by popular SSL libs such as openssl, the cipher has/may not have been selected. This is a potential interworking problem when h2 is proposed, only to have the connection shutdown with INADEQUATE_SECURITY afterwards.
> 
> I am not sure what is the best way to address this. Limiting the cipher list to only highest grade is often not an option for a server. Any advice appreciated.

If you don't want to limit ciphers (but if you need to be PCI DSS
compliant, you can limit it a lot, the only non-h2 ciphers you
need is ECDHE-{RSA,ECDSA}-AES256-CBC (for Apple products).

And you can also priorize the H2 ciphers over the rest, which
should make the handshake go properly.

-Ilari

alpn + ciphers Stefan Eissing
Re: alpn + ciphers Ilari Liusvaara
Re: alpn + ciphers Stefan Eissing
Re: alpn + ciphers Martin Thomson