[Ach] Vote for new Cipherstring B [Was: Issue with OpenSSL >0.9.8l]

Torsten Gigler torsten.gigler at owasp.org
Wed Jun 4 16:19:07 CEST 2014


may I suggest to write a policy how to setup the cipher string and the
order of its ciphers.
>From the most important to the less important rule (e.g. like from Perfect
Secrecy ... Bit len of the Hash).

I see, that it may take a while to change chipher strings, if you maintain
a lot of systems. So I'd prefer to include reliable ciphers that are
planned for future use, even if they are not or rarely supported by
browsers today (e.g. TLS_DHE_RSA_WITH_AES_256_GCM_SHA384).

Perhaps it could be an idea to have a 'CipherString C' for latency Servers.
Perhaps there you could place ECDHE with higher priority than DHE, and
AES-256 higher than AES-128.

... only my 2 cents...

Kind regards

2014-06-04 15:24 GMT+02:00 Aaron Zauner <azet at azet.org>:

> Hi Philip,
> Philipp Gühring wrote:
> > Hi,
> >
> > I dont't mind dropping *256, but I currently believe that SHA384 is the
> > only secure hash in the SHA2 family, all other hashes leak their
> > complete internal state. Length-Extension-Attack...
> > From security point of view, I would drop SHA2-256 and SHA2-512, and
> > promote SHA2-384.
> > But I do not know what that means interoperability-wise.
> There is no support for SHA384 with 128 bit symmetric ciphers in TLS:
> https://www.iana.org/assignments/tls-parameters/tls-parameters.xhtml
> So,.. keeping them is completely useless if we drop *256.
> Aaron
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