A5 Cipher

[cryptlist@ubik.demon.co.uk]

oml@sysrx.uk.com wrote:
> 
> 
> > -----Original Message-----
> > From: ukcrypto-admin@chiark.greenend.org.uk
> > [mailto:ukcrypto-admin@chiark.greenend.org.uk]On Behalf Of Markus Kuhn
> > Sent: 11 July 2002 17:42
> > To: ukcrypto@chiark.greenend.org.uk
> > Subject: Re: A5 Cipher
> >
> >
> > "Owen Lewis" wrote on 2002-07-10 11:55 UTC:
> > > Does anyone here have an authoritative list of the GSM A5
> > cipher variants
> > > (A5/0/1/2 etc) and a list of countries that use each variant?
> >
> > I'd be surprised if you can find an "authoritative list".

Agreed, especially with the recent relaxations on crypto export.  I expect that countries that previously had the weaker flavours will now have newer network providers (or maybe even cells?) with stronger variants.

I believe the original distribution was along the lines of:
A5/1 (strong version) for COCOM member countries only
A5/2 (weak) for other 'Western' countries
A5/0 (none) for others, e.g. Eastern Europe

> So, what's the vibe on the streets of Silicon Fen re. A5/3 then?

Announced in a press release on just a few days ago, on 3rd July:
http://www.etsi.org/pressroom/previous/2002/3algorithm.htm

It looks (IMHO) much stronger than A5/1.

> I read somewhere the other day that cipher for G3PP privacy is going to be
> open source and a *real* cipher (and US of course). Well, we shall see if
> pigs can fly. Personally, I shan't be holding my breath for it.

The G3PP cipher, Kasumi, is Japanese - developed by Mitsubishi - and the one 
adopted by ETSI as A5/3.

See:
http://www.research.att.com/~janos/3gpp.html
http://www.etsi.org/pressroom/previous/2000/algo3gpp.htm 

and the algorithms should be here (it isn't working just now though):
http://www.etsi.org/dvbandca/


Cheers,
Anthony Naggs