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Date:   Wed, 18 Aug 2021 22:18:03 -0700
From:   Eric Biggers <ebiggers@kernel.org>
To:     Andrew Bartlett <abartlet@samba.org>
Cc:     Jeremy Allison <jra@samba.org>, Steve French <smfrench@gmail.com>,
        linux-cifs <linux-cifs@vger.kernel.org>,
        Herbert Xu <herbert@gondor.apana.org.au>,
        samba-technical <samba-technical@lists.samba.org>,
        David Howells <dhowells@redhat.com>,
        Steve French <sfrench@samba.org>, keyrings@vger.kernel.org,
        Linux Crypto Mailing List <linux-crypto@vger.kernel.org>,
        Ard Biesheuvel <ardb@kernel.org>,
        Denis Kenzior <denkenz@gmail.com>
Subject: Re: [PATCH 0/2] crypto: remove MD4 generic shash
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On Thu, Aug 19, 2021 at 03:49:14PM +1200, Andrew Bartlett wrote:
> I know neither MD4 nor HMAC-MD5 is not flavour of the month any more,
> with good reason, but we would not want to go with way of NFSv4 which
> is, as I understand it, full Kerberos or bust (so folks choose no
> protection).

I'm not sure you understand how embarrassing it is to still be using these
algorithms.  MD4 has been broken for over 25 years, and better algorithms have
been recommended for 29 years.  Similarly MD5 has been broken for 16 years and
better algorithms have been recommended for 25 years (though granted, HMAC-MD5
is more secure than plain MD5 when properly used).  Meanwhile SHA-2 is 20 years
old and is still considered secure.  So this isn't something that changes every
month -- we're talking about no one bothering to do anything in 30 years.

Of course, if cryptography isn't actually applicable to the use case, then
cryptography shouldn't be used at all.

- Eric