Re: [Cfrg] 1024 bit RSA

Paul Grubbs <pag225@cornell.edu> Fri, 04 November 2016 19:37 UTC

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From: Paul Grubbs <pag225@cornell.edu>
Date: Fri, 4 Nov 2016 15:37:06 -0400
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To: Derek Atkins <derek@ihtfp.com>
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Cc: Cfrg <cfrg@irtf.org>
Subject: Re: [Cfrg] 1024 bit RSA
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Recall also that any cryptanalytic advances that improve the asymptotic
complexity of factoring could cause 1024-bit keys to fall much sooner than
2025.

On Fri, Nov 4, 2016 at 12:33 PM, Derek Atkins <derek@ihtfp.com> wrote:

> "Erik Andersen" <era@x500.eu> writes:
>
> > I participate in IT smart grid standardization within IEC TC57 WG15. A
> couple
> > of standards under development still allow 1024 bit RSA keys for
> so-called
> > backward compatibility. I have so far not been able to change that. My
> > question is now. Is there any information available for how long time or
> how
> > much effort it takes to break  a 1024 bit RSA key?
>
> Just remember that RSA1024 provides approximately 80 bits of security.
> As Phill mentioned that's currently out of the range of public
> resources, but probably not SIGINT.
>
> What symmetric ciphers are they using?  If they're using AES-128, then I
> would ask why they would support a key agreement/signature that's less
> secure?  Getting 128-bit public key security is rather straightforward
> these days, even in pretty small systems.
>
> > Erik
>
> -derek
> --
>        Derek Atkins                 617-623-3745
>        derek@ihtfp.com             www.ihtfp.com
>        Computer and Internet Security Consultant
>
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