Re: [Discuss-gnuradio] GPRS GNU Radio support

[Tony Torzillo]

Thanks.  Encryption issues aside - has anyone worked on capturing GSM
and/or GPRS with a GNU radio?

On Wed, 26 Feb 2003, Chris Albertson wrote:

> Date: Wed, 26 Feb 2003 23:51:44 -0800 (PST)
> From: Chris Albertson <address@hidden>
> To: Tony Torzillo <address@hidden>, address@hidden
> Subject: Re: [Discuss-gnuradio] GPRS GNU Radio support
>
>
> You can brute force the key by using a large number of
> cheap PCs. At my company they have a formal policy for
> replacing Older PCs.  They remove some fixed number of
> machines each week.  Replacing the oldest ones with new
> ones.  350Mhz and 500Hhz Pentiums are then surplused
> at the rate of a few per day.
> There are people who have connected roomfulls of these and
> used them to solve large problems.  So in figuring your
> budget figure large scale compute power is nearly free
> if you have the time to collect the computers.
>
> --- Tony Torzillo <address@hidden> wrote:
> > I wonder if anyone has done any work on developing a GNU radio
> > capable of
> > receiving GPRS signals.
> >
> > I want to know what it would take to set up a simulated test
> > environment
> > in which a GNU radio could receive and decrypt a GPRS signal.  GPRS
> > uses a
> > form of A5 encryption called GEA.  Would be a proof of concept
> > environment
> > to test the actual strength of over the air GPRS encryption.
> >
> > Does anyone know what hardware would be necessary for the reception
> > of a
> > GPRS signal, software for demodulating the signals, and also code to
> > attempt to brute force the GEA encryption.
> >
> > I would like to know answers to the following questions:
> >
> > 1.  What hardware would be necessary for receiving and demodulating
> > the
> > GPRS signal?  How much would such hardware cost?
> > 2.  If it is possible to demodulate and receive the signal with a
> > software
> > radio has code already been written to do so?
> > 3.  Is the GEA algorithm susceptible to the same cryptographic flaws
> > as
> > A5, and has someone developed code to exploit these flaws and decrypt
> > traffic?
> > 4.  What resources would be required for brute forcing the keyspace?
> >
> > In answering the above questions I am trying to answer the following
> > question:
> >
> > Is receiving and decrypting a GPRS signal difficult enough that the
> > GEA
> > encryption can be relied upon to prevent eavesdropping of sensitive
> > information, or is it cheap and easy to eavesdrop GPRS signals?
> >
> > I've been told that it would require over $200,000 worth of equipment
> > to
> > eavesdrop on a GPRS signal and that the GEA encryption algorithm is
> > of
> > sufficient strength to prevent decryption within a reasonable time
> > frame.
> >
> > Thanks!
> >
> >
> >
> >
> > _______________________________________________
> > Discuss-gnuradio mailing list
> > address@hidden
> > http://mail.gnu.org/mailman/listinfo/discuss-gnuradio
>
>
> =====
> Chris Albertson
>   Home:   310-376-1029  address@hidden
>   Cell:   310-990-7550
>   Office: 310-336-5189  address@hidden
>   KG6OMK
>
> __________________________________________________
> Do you Yahoo!?
> Yahoo! Tax Center - forms, calculators, tips, more
> http://taxes.yahoo.com/
>