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Re: HTTP2 Expression of Interest

From: Phillip Hallam-Baker <hallam@gmail.com>
Date: Wed, 18 Jul 2012 00:33:21 -0400
Message-ID: <CAMm+LwgoUk1HAWakqurgTXijGWerH2GCEkh7o37hRiYM=jLR4g@mail.gmail.com>
To: Mike Belshe <mike@belshe.com>
Cc: Martin J. Dürst <duerst@it.aoyama.ac.jp>, Doug Beaver <doug@fb.com>, Willy Tarreau <w@1wt.eu>, "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
No, RC4 is almost NEVER used on its own as you seem to imagine.

What is used is actually RC4 + SHA1. And the real security value
actually comes from the integrity check, not the stream cipher.

For HTTP/2.0 you would be much better off using AES-GCM which does
encryption and integrity in one operation.


On Wed, Jul 18, 2012 at 12:16 AM, Mike Belshe <mike@belshe.com> wrote:
>
>
> On Tue, Jul 17, 2012 at 8:59 PM, Phillip Hallam-Baker <hallam@gmail.com>
> wrote:
>>
>> RC4 is cheap but SHA2 is not.
>>
>> Encryption without authentication is worthless. The principal security
>> objective in TLS is to provide integrity, not confidentiality. If you
>> lose integrity you are going to lose confidentiality even with 128 bit
>> encryption.
>>
>>
>> RC4 is a stream cipher. It is fast but thats about all that can be
>> said in its favor. If I care about confidentiality I am not going to
>> want a stream cipher.
>
>
> I believe RC4 is excellent for almost all cases.  It is certainly used on
> millions of sites today just fine.
>
> If the alternative is no security (e.g. arguing for no TLS), we can probably
> agree that RC4 is more secure than that! :-)  Obviously, if you want even
> stronger security, you can opt in to using other crypto algorithms - those
> are configurable through TLS today.  No problem. Requiring TLS with HTTP/2.0
> would not need to require an expensive symmetric crypto algorithm.
>
> Mike
>
>
>
>
>>
>>
>>
>> On Tue, Jul 17, 2012 at 11:44 PM, Mike Belshe <mike@belshe.com> wrote:
>> >
>> >
>> > On Tue, Jul 17, 2012 at 7:35 PM, "Martin J. Dürst"
>> > <duerst@it.aoyama.ac.jp>
>> > wrote:
>> >>
>> >> Hello Doug, everybody,
>> >>
>> >>
>> >> On 2012/07/18 7:11, Doug Beaver wrote:
>> >>
>> >>>    * Symmetric crypto costs are not much higher; I think Akamai quoted
>> >>> 10-20%
>> >>>      in their response. I think the costs aren't a big deal for major
>> >>> sites;
>> >>
>> >>
>> >> Just a quick question: I think if we could shave off 10-20% of the
>> >> bandwidth with some new technique, we'd all go for it.
>> >
>> >
>> > Symmetric crypto (RC4) is super super cheap - a couple of XORs -
>> > definitely
>> > not 10-20% of CPU.  I'd like to see that measured again before taking
>> > action
>> > upon it.  Obviously, if you use expensive crypto (presumably because you
>> > want it), some algorithms take more CPU
>> >
>> > mike
>> >
>> >>
>> >>
>> >> So why are we okay with 10-20% more processing costs for everybody, but
>> >> not with 10-20% more bandwidth? What's different between processing
>> >> costs
>> >> and bandwidth?
>> >>
>> >> Regards,   Martin.
>> >>
>> >
>>
>>
>>
>> --
>> Website: http://hallambaker.com/
>
>



-- 
Website: http://hallambaker.com/
Received on Wednesday, 18 July 2012 04:33:49 GMT

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