RE: [PATCH 1/2] crypto: sm3 - add a new alias name sm3-256

Van Leeuwen, Pascal
2020-02-11T07:57:58Z

> -----Original Message-----
> From: linux-crypto-owner@vger.kernel.org <linux-crypto-owner@vger.kernel.org> On Behalf Of Ken Goldman
> Sent: Monday, February 10, 2020 7:03 PM
> Cc: linux-crypto@vger.kernel.org; linux-integrity@vger.kernel.org; linux-security-module@vger.kernel.org; linux-
> kernel@vger.kernel.org
> Subject: Re: [PATCH 1/2] crypto: sm3 - add a new alias name sm3-256
>
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> On 2/10/2020 12:01 PM, Van Leeuwen, Pascal wrote:
> > Well, the current specification surely doesn't define anything else and is
> > already over a decade old. So what would be the odds that they add a
> > different blocksize variant_now_ AND still call that SM3-something?
>
> I just got a note from a cryptographer who said there were discussions
> last year about a future SM3 with 512 bit output.
>
> Given that, why not plan ahead and use sm3-256? Is there any downside?
> Is the cost any more than 4 bytes in some source code?
>

It is actually exported as "sm3" by all implementations, it's just this one reference that was off.
So fixing that one reference is less effort than fixing all implementations.
I don't think anyone cares about the 4 bytes of source code ...

As for SM3-512: that would by silly, considering recent attacks found against similar
Merkle-Darmgard structures. Then again, I'm not talking to Chinese cryptographers.
In any case, what would be the problem with having "sm3" and "sm3-512"?
Note that nobody in the world refers to the current SM3 as "SM3-256".

Regards,
Pascal van Leeuwen
Silicon IP Architect Multi-Protocol Engines, Rambus Security
Rambus ROTW Holding BV
+31-73 6581953

Note: The Inside Secure/Verimatrix Silicon IP team was recently acquired by Rambus.
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