Re: [TLS] TLS 1.2 draft comments

["Omirjan Batyrbaev" <batyr@xxxxxxxxxxxx>]

see inserted:
Subject: Re: [TLS] TLS 1.2 draft comments


> "Omirjan Batyrbaev" <batyr@xxxxxxxxxxxx> writes:
>
> >> 2. CIPHERSPEC, EXPORT
> >>
> >> If the 40-bit export ciphersuites are being deprecated,
> >
> > But some constrained enviroments do need 40-bit "export" ciphersuites.
>
> I'm not aware of any such environment. Can you please > name them?

Some embeded systems, for example cheap EPC RFID tag. The Generation 2 tag
today does not even have a cryptographic hash function, etc.

>
>
> > Besides since the NULL encryption ciphersuites exist why can't 40-bit
> > "export" ciphersuites exist too?
>
> Because there's no good reason for them to exist and the key
> weakening primitive adds substantial complexity to the
> protocol.
>
>
> > If needed the TLS client and server always
> > can neogtiate a stronger encryption so why the depreciation (and what it
> > would exactly mean to the implementations).
>
> Here's the relevant text from 4346. So, actually, they're already
> deprecated.
>
>    When SSLv3 and TLS 1.0 were designed, the United States restricted
>    the export of cryptographic software containing certain strong
>    encryption algorithms.  A series of cipher suites were designed to
>    operate at reduced key lengths in order to comply with those
>    regulations.  Due to advances in computer performance, these
>    algorithms are now unacceptably weak, and export restrictions have
>    since been loosened.  TLS 1.1 implementations MUST NOT negotiate
>    these cipher suites in TLS 1.1 mode.  However, for backward
>    compatibility they may be offered in the ClientHello for use with TLS
>    1.0 or SSLv3-only servers.  TLS 1.1 clients MUST check that the
>    server did not choose one of these cipher suites during the
>    handshake.  These ciphersuites are listed below for informational
>    purposes and to reserve the numbers.
>
> -Ekr
>


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