Re: [Cfrg] New draft on the transition from classical to post-quantum cryptography

"Dearlove, Christopher (UK)" <> Tue, 09 May 2017 09:22 UTC

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From: "Dearlove, Christopher (UK)" <>
To: "Blumenthal, Uri - 0553 - MITLL" <>, Paul Hoffman <>
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Thread-Topic: [Cfrg] New draft on the transition from classical to post-quantum cryptography
Date: Tue, 09 May 2017 09:16:52 +0000
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Subject: Re: [Cfrg] New draft on the transition from classical to post-quantum cryptography
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The NSA, who probably have the longest timescales, say (, on page 8):

"Algorithms often require 20 years to be fully deployed on NSS. NSS equipment is often used for 30 years or more. National security information intelligence value is often 30 years (sometimes more) although it may vary depending on classification, sensitivity, and subject."

[NSS = National Security System]

Christopher Dearlove
Senior Principal Engineer
BAE Systems Applied Intelligence Laboratories

T:  +44 3300 467500  |  E:

BAE Systems Applied Intelligence, Chelmsford Technology Park, Great Baddow, Chelmsford, Essex CM2 8HN.
BAE Systems Applied Intelligence Limited
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-----Original Message-----
From: Cfrg [] On Behalf Of Blumenthal, Uri - 0553 - MITLL
Sent: 08 May 2017 15:35
To: Paul Hoffman
Subject: Re: [Cfrg] New draft on the transition from classical to post-quantum cryptography

On 5/8/17, 10:28 AM, "Paul Hoffman" <> wrote:
    > Wouldn’t you agree that for long-term documents (those that need to 
    > survive for 15+ - 20+ years from now) the “need to change” is now 
    > with a pretty high probability?
    No. That is, I haven't seen evidence that there will be quantum 
    computers in 15 to 20 years from now that will be able to break 
    classical cryptography using current key sizes. The same is true if you 
    said "50 years". 

First, I’m sure there are documents now that need a “secure life” longer than 20 or even 50 years.

    Of course, I might have missed something in the early 
    research for the -00 draft, so if you have pointers to such 
    calculations, that would be great.

Alas, my crystal ball is out of order right now. But scientific progress tends to be not exactly predictable/calculate-able. E.g., did you expect to talk about “quantum computers breaking crypto” 20 years ago? I didn’t.
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