Velocity Reviews - Computer Hardware Reviews

Velocity Reviews > Newsgroups > Computing > NZ Computing > Encrypted Digital Radios for the Cops

Reply
Thread Tools

Encrypted Digital Radios for the Cops

 
 
Lawrence D'Oliveiro
Guest
Posts: n/a
 
      05-21-2009
NZ police are finally going to get a radio system that prevents people from
eavesdropping on their communications.

I wonder what happens the first time a crim steals one of these? Will they
able to remotely revoke the key for that radio to stop it being part of the
network?

Also I wonder how vulnerable they will be to traffic analysis. Often you can
deduce something is up simply from the increased amount of chatter on a
channel, particularly if it's concentrated in your neighbourhood.

 
Reply With Quote
 
 
 
 
ted.8367@gmail.com
Guest
Posts: n/a
 
      05-21-2009
On May 21, 12:36*pm, Lawrence D'Oliveiro <l...@geek-
central.gen.new_zealand> wrote:
> NZ police are finally going to get a radio system that prevents people from
> eavesdropping on their communications.


About time too


>
> I wonder what happens the first time a crim steals one of these? Will they
> able to remotely revoke the key for that radio to stop it being part of the
> network?


They would be able to in any decent system. And be able to locate the
radio remotely too.

>
> Also I wonder how vulnerable they will be to traffic analysis. Often you can
> deduce something is up simply from the increased amount of chatter on a
> channel, particularly if it's concentrated in your neighbourhood.


I don't see an easy way to get around the traffic analysis. But it's
more difficult for the crims than just turning on a scanner.
 
Reply With Quote
 
 
 
 
JohnO
Guest
Posts: n/a
 
      05-21-2009
On May 21, 1:15*pm, vitw <(E-Mail Removed)> wrote:
> On Wed, 20 May 2009 17:55:00 -0700, ted.8367 wrote:
> > I don't see an easy way to get around the traffic analysis. *But it's
> > more difficult for the crims than just turning on a scanner.

>
> This will just create another 'arms race', akin to CSS, DRM and the
> various 'copy protection' schemes. Nothing has stood the test of time.


Except there's no army of encryption hackers amongst the criminal and
gang fraternity as there is amongst the world's computer users.

>
> However, these radios might well reduce the number of crims who are able
> to eavesdrop - for a time.


So far nobody has managed to crack the encryption used in digital tv
such as SkyDigital in NZ.

>
> Encrypted radios will always have a vulnerability - the fact that the
> ciphertext has to be rendered into cleartext somewhere along the way.
> It's the same vulnerability that has allowed all the various DRM schemes
> to get cracked.
>
> If they're using public key crypto, there has to be some 'out of band'
> means of distributing the public keys - typically, flashing them into the
> devices when the car is being maintained. You just need one dirty officer
> or contractor in the service chain and the whole thing breaks.
>
> Top level crime mobs - eg South American coke gangs - would very readily
> invest money into cracking these devices. For them it's sound business
> sense.


Well, the Medellin Cartel was cracked because they were careless with
their cellular phones. I think you credit them with too much smarts.

>
> For a talented but miscreant computer science student, it can be very
> tempting if a gangster knocks on your door with one of these radios under
> his arm and says "here's $2000 now just for talking to me, I'll pay you
> another $30000 if you can crack this radio and come up with a system
> using off-the-shelf components which can listen in on police."
>
> Once the crypto is cracked, the software will leak further afield.

..

 
Reply With Quote
 
victor
Guest
Posts: n/a
 
      05-21-2009
vitw wrote:
> On Wed, 20 May 2009 17:55:00 -0700, ted.8367 wrote:
>
>> I don't see an easy way to get around the traffic analysis. But it's
>> more difficult for the crims than just turning on a scanner.

>
> This will just create another 'arms race', akin to CSS, DRM and the
> various 'copy protection' schemes. Nothing has stood the test of time.
>
> However, these radios might well reduce the number of crims who are able
> to eavesdrop - for a time.
>
> Encrypted radios will always have a vulnerability - the fact that the
> ciphertext has to be rendered into cleartext somewhere along the way.
> It's the same vulnerability that has allowed all the various DRM schemes
> to get cracked.
>
> If they're using public key crypto, there has to be some 'out of band'
> means of distributing the public keys - typically, flashing them into the
> devices when the car is being maintained. You just need one dirty officer
> or contractor in the service chain and the whole thing breaks.
>
> Top level crime mobs - eg South American coke gangs - would very readily
> invest money into cracking these devices. For them it's sound business
> sense.
>
> For a talented but miscreant computer science student, it can be very
> tempting if a gangster knocks on your door with one of these radios under
> his arm and says "here's $2000 now just for talking to me, I'll pay you
> another $30000 if you can crack this radio and come up with a system
> using off-the-shelf components which can listen in on police."
>
> Once the crypto is cracked, the software will leak further afield.
>


One flaw in your reasoning that it is akin to the CSS vulnerability is
that pressed optical disks have a single fixed key.
P25 radios have over the air re-keying for their AES encryption, its not
flashed when the car is maintained, you are definitely pulling that out
of your arse.
Check out the spec at Tait's site and the govt briefing docs that Google
found http://www.e.govt.nz/standards/e-gif...5-briefing.doc
 
Reply With Quote
 
Lawrence D'Oliveiro
Guest
Posts: n/a
 
      05-21-2009
In message <4a14b944$(E-Mail Removed)>, vitw wrote:

> On Wed, 20 May 2009 17:55:00 -0700, ted.8367 wrote:
>
>> I don't see an easy way to get around the traffic analysis. But it's
>> more difficult for the crims than just turning on a scanner.

>
> This will just create another 'arms race', akin to CSS, DRM and the
> various 'copy protection' schemes. Nothing has stood the test of time.


SSH/SSL has stood up pretty well. As has RSA (since 1976), triple-DES (slow
as it is) ...

Your confusion between copy-protection/DRM and securing communication
channels shows a lack of understanding of two very different situations.

> If they're using public key crypto, there has to be some 'out of band'
> means of distributing the public keys - typically, flashing them into the
> devices when the car is being maintained. You just need one dirty officer
> or contractor in the service chain and the whole thing breaks.


Think of all the public keys currently being distributed all over the
Internet without issues of this sort--like the hundred or so CA certs built
into the Web browser that you use, for example. Subverting those could be
worth a lot of money in online fraud. Yet in over a decade or more of using
SSL, it just hasn't happened. Why not?

 
Reply With Quote
 
 
 
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are Off


Similar Threads
Thread Thread Starter Forum Replies Last Post
Bluetooth Radios =?Utf-8?B?Q2xhaXI=?= Wireless Networking 1 11-26-2005 04:26 AM
onselectedindexchanged on Radios Angela ASP .Net 0 11-22-2004 12:21 PM
RIAA Claims Music On Car Radios Meant Only For Original Vehicle Owner!!!! tgilb Computer Support 3 08-11-2004 07:52 PM
Formatting Radios Angela ASP .Net 4 07-30-2004 03:12 PM
DVD Verdict reviews: COPS: SHOTS FIRED, COPS: CAUGHT IN THE ACT, and more! DVD Verdict DVD Video 0 04-15-2004 09:04 AM



Advertisments