Re: [Discuss-gnuradio] GPRS GNU Radio support

[Chris Albertson]

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/