Re: [Cfrg] likelihood that someone has a quantum computer

William Whyte <> Tue, 14 January 2014 02:04 UTC

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From: William Whyte <>
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Date: Mon, 13 Jan 2014 21:04:12 -0500
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To: arne renkema-padmos <>,
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Subject: Re: [Cfrg] likelihood that someone has a quantum computer
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Hi Arne,

So is the idea that all devices have to implement both algorithms? Is
there a mechanism in place for declaring one broken and requiring that the
other is used at all times?

TBH I'm less concerned about catastrophic failure of symmetric algorithms
than public-key algorithms, but I'm very interested in processes to
replace algorithms.



-----Original Message-----
From: Cfrg [] On Behalf Of arne renkema-padmos
Sent: Monday, January 13, 2014 9:57 AM
Subject: Re: [Cfrg] likelihood that someone has a quantum computer

On 13/01/14 11:48, William Whyte wrote:
> I don't think you can say that just because there have been few
> discontinuities in the security of algorithms there will be no
> discontinuities in the future. There might be, and if it does happen
> unexpectedly it'll be a big problem. It's not a problem we need to
> work on right now, but, again, that makes this a really good time >
to address it.

It makes sense to have a fallback algorithm set, as ETSI has done with the
3GPP algorithms:

They standardised both KASUMI and SNOW 3G with the requirements for SNOW
3G as fallback algorithm being:
* maximizing "cryptographic distance" from KASUMI
* minimizing potential vulnerability to algebraic attacks


Arne Renkema-Padmos
Doctoral researcher
CASED, TU Darmstadt
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