Spread Spectrum Digital Modem?

GlassWalkerTheurge asks: "I was wondering if anyone is aware of any spread spectrum digital modem technology that would make a mobile location (i.e. car, etc.) able to create a secure link to a ground station (i.e. home etc.) using multiple (say 4) digital cell phones on both ends. The traffic would be encrypted and spread over the 4 digital modems according to an algorythm available to both sides (negotiated when the secure link is established.) If it does not exist, anyone know if it is doable? I was thinking using a hardware encryption based on a periodically changed key (physical card?) that contained a 4096 bit key (software encryption type). An idea for my dream car."

Re:Come on /. you can do better.

[GlassWalkerTheurge]

CDMA? That sounds good, where can I find out more about that? I already looked at the MEGACAR, cool. Not the solution I was looking for. I am looking in a more economical/secure direction. I searched /. before I posted thank you 8-).

Re:good idea, but

[GlassWalkerTheurge]

he he he he.... but nice cell phone sales person, I need 8 cell phones I need cell phone to cell phone calls to be free I need 120 minutes in a pool a month over all phones you can charge me what you want for any additional minutes. I often see cell plans that don't charge for cell to cell calls. I would just work out one of those. The inital cost would be fairly high for the cell phones, but that would be ok. I had thought that digital cell phones would have around 56k as long as their would be no analog link. A fast pentiumII handling crypt/decrypt on either end should make this sing.

Re:ricochet?

[GlassWalkerTheurge]

No, I was not looking for non-cell stuff. I was looking for somthing supported everywhere.

One major flaw

[atdot]

Is that there is no such thing as a digital modem. You'll have to leave that part out of your design. -- --atdot

good idea, but

[cheeserd00d]

this sounds like a good idea and all but wouldn't it be a little slow for any practical applications, even with 4 cell phones? plus factor in the time it will take to encrypt/decrypt everything

the biggest problem i would find with this is cost, having 4 cell phones on each end on and connected would be quite expensive

Better solutions exist...maybe.

[yakfacts]

Several companies produce fast wireless LAN solutions that--depending on distance--can provide higher performance at a lower-cost than running four cell phones concurrently.

Enterasys [enterasys.com] (part of the former cabletron) offers the DEC wireless network technology. I noticed they have a press release about the use of such a system in Australia on today's press release. Pacific Wireless rolls out Wireless IP [enterasys.com]

Come on /. you can do better.

[The Iconoclast]

CDMA (Code Division Multiple Access) cellphones are ALREADY spread spectrum. That's how they work. They pick a frequency within their band and send out a little burst of data with a code (key) at the front, then pick another frequency. The towers listen to the whole band and reassemble all the chuncks into a data stream.

Anyway, at least check the old /. archives for anything relavent to the question. Look at the Megacar [slashdot.org]. 1 car, 16 cell phones.

A wealthy eccentric who marches to the beat of a different drum. But you may call me "Noodle Noggin."

ricochet?

[eMBee]

it seems that what you are really looking for is something like ricochet [ricochet.com]. they provide 128kbit/s mobile networking, which you could use from your car or anywhere else.
unfortunately they only cover high populated areas, so you could use it for your work commute but it wouldn't work for your holiday trip going out of town...

greetings, eMBee
--

EQL + crypto VPN + modems

[SEWilco]

Well, just hook up your favorite cellular modems to their phones. Then use EQL [indyramp.com] to configure a single network link through all those modems. Then use some encrypted VPN tech [linuxdoc.org] to create an encrypted link through the EQL device. The encrypted packets will then be splattered through the modems, and they're protected from listeners.

Notice that whether the phones use spread spectrum at the hardware level or not, they can still be theoretically monitored. And any collection of phones will be hard to monitor, as they'll be using their usual methods of avoiding interference with each other -- whether they use TDM, multiple frequencies, whatever. Or use several different types of phones with different types of networks...

Encryption is faster than you think

[goingware]

I've found that one a 450 MHz Pentium III laptop [goingware.com] I can play MPG, QuickTime or ASF movies of a PGPDisk encrypted partition with no loss in performance.

I think this is with a 5000 RPM disk.

While on this topic, please read my page on Why You Should Use Encryption [goingware.com]

While encryption is indeed computationally expensive, it is not nearly as computationally expensive as badly written GUI code, and that's what's usually running on modern computers. Encryption software is generally quite optimized, while the crud we call shrink-wrap software is a poor excuse for engineering.

I also refer you to the Risks Forum [ncl.ac.uk]