Key length

[Peter Tomlinson]

David,

Here's the reason for a 2048 bit key: the situation where one wishes to send
a message that one needs to keep secret, and there are worries that the
opposition might be able to decipher it within a dangerously short period of
time (less than 30 years) if the key were shorter.

Peter
----- Original Message -----
From: "Owen Lewis" <oml@sysrx.uk.com>
To: <ukcrypto@chiark.greenend.org.uk>
Sent: Tuesday, July 09, 2002 2:44 PM
Subject: RE: ukcrypto digest, Vol 1 #783 - 8 msgs


>
>
> > -----Original Message-----
> > From: ukcrypto-admin@chiark.greenend.org.uk
> > [mailto:ukcrypto-admin@chiark.greenend.org.uk]On Behalf Of Richard
> > Clayton
> > Sent: 09 July 2002 12:47
> > To: UKcrypto@chiark.greenend.org.uk
> > Subject: Re: ukcrypto digest, Vol 1 #783 - 8 msgs
> >
> >
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> >
> > In article <5.1.0.14.0.20020709122826.029d9428@server1.nigelwhitfield.co
> > m>, MS <ms@PyroSkin.com> writes
> >
> > >At 07:47 09/07/2002 +0100, you wrote:
> > >> > -----Original Message-----
> > >> > [mailto:ukcrypto-admin@chiark.greenend.org.uk]On Behalf Of James
> > >> > Hammerton
> > >> > Sent: 08 July 2002 15:54
> > >>
> > >>
> > >>In the particular of your 'banning PGP' example, it does seem
> > to fall at the
> > >>first fence. There are no longer any restrictions on the free
> > movement of
> > >>unclassified cipher programs within the EU. No EU country can
> > abrogate this
> > >>agreement unilaterally any more than it can any other intra-EU trade
> > >>agreement it has entered into.
> > >
> > >Oops!   The use, or even possession of, PGP or a PGP-encoded message is
> > >illegal in France....
> >
> > not these days (or indeed since January 1999)
>
> Quite so. And it was only illegal before that if the possession and use
was
> unlicensed.
>
> Changes in law and regulation rarely lead public opinion but follow it
with
> a drag time of some years.
>
> If there is any watershed in general demand to electronic encryption
> systems, it must be the advent of the PC. It is the omni-presence of
cheap,
> small and powerful computational engines for data processing, storage and
> communication that made possible the general use of cryptography. Also,
> quite arguably, it was the mass adoption of such engines that in itself
> created the need for a wide deployment of crypto systems.  I don't think
> that people's perceptions of their security needs changed so much as did
the
> means by which information was communicated and stored.
>
> Imagine how popular (and how useless for general purposes) PGP would be
if,
> to use it at all, one had to build an extension onto the house to garage a
> Ferranti No 2. Putting to one side the large, expert service crew and the
> need for a climatically controlled environment, does anyone have access to
> sufficient of the specs for a No2 to calculate how long one would need to
> (a) generate a 2048 bit key pair - I remember how long it used to take to
> generate a 512 bit key pair on a 10MHz 286 box :-) and(b)decipher a 256Mb
> file enciphered with PGP using a 2048 bit key?
>
> Owen
>
>
>
>