Encrypt cell phones calls!!!!
Moderators: adafruit_support_bill, adafruit

Please be positive and constructive with your questions and comments.

Encrypt cell phones calls!!!!

by perse0 on Mon Aug 03, 2009 12:32 pm


im new in the forum, who knows about encrypting phone calls?

thanks in advanced!!
Posts: 1
Joined: Mon Aug 03, 2009 12:25 pm

Re: Encrypt cell phones calls!!!!

by franklin97355 on Mon Aug 03, 2009 10:29 pm

You could always talk in pig latin. :D

Posts: 15031
Joined: Mon Apr 21, 2008 2:33 pm
Location: Lacomb, OR.

Re: Encrypt cell phones calls!!!!

by eil on Tue Aug 04, 2009 1:59 am

What kind of calls? VoIP calls can be encrypted relatively easily, there are loads of ways to do it.

Landline phones? I'm not sure, but I believe there are devices out there to do it. Or you could roll your own with a pair of old modems.

Cell phone? Short answer: No. Long answer: In the U.S. at least, the carriers can't encrypt the calls because CALEA requires them to accommodate law enforcement wiretaps. Plus, encryption would add overhead to their precious bandwidth. Plus, the lossy compression performed on a digital cell phone voice stream mangles normal audio so as to be just a hair above completely unintelligible thus encrypted audio certainly wouldn't make it through.
Posts: 440
Joined: Sun Aug 31, 2008 11:09 pm

Re: Encrypt cell phones calls!!!!

by ILUsion on Thu Aug 06, 2009 5:05 pm

As eil points out, cell phone calls are heavily compressed with lossless compression specially suited for the human voice (even DTMF codes get mangled; just to give an idea: a gsm cell phone compresses its audio track to a 13 kbps stream (FYI: an mp3 file with sub-cd quality audio requires 128 kbps for stereo sound)).

But as a first concept, if delay is not really a problem: reversed speech is not clearly understandable and might make it through the compression. Though it's not as good as real encryption, it's something that might work (I haven't tested it). And perhaps even a bit better delay-wise: splitting the audio-stream in chunks (of a few hundred ms or even a few seconds), can lower the delay but I guess the shorter each chunk of reverse audio, the better it could become to understand everything.

For shorted messages, it might work to just send audio files through MMS; and those audio files can of course be altered in any way you want, I guess.

So the most secure option would be to use VoIP, which can be encrypted without problem.
Posts: 1
Joined: Thu Aug 06, 2009 4:49 pm

Re: Encrypt cell phones calls!!!!

by Sorceress Sarah on Sun Aug 16, 2009 4:07 pm

Ya know, I can't imagine a more effective way to attract the attention of Echelon. . .
I'm not a freak. . . I'm a PROTOTYPE!!!
User avatar
Sorceress Sarah
Posts: 100
Joined: Sat Jun 20, 2009 2:07 pm

Re: Encrypt cell phones calls!!!!

by Bandit on Wed Nov 11, 2009 5:14 am

You could learn to talk like a chav, no one would understand you :lol:
Posts: 45
Joined: Mon Dec 01, 2008 1:16 pm

Re: Encrypt cell phones calls!!!!

by Entropy on Sat Jan 02, 2010 12:29 pm

perse0 wrote:Hello,

im new in the forum, who knows about encrypting phone calls?

thanks in advanced!!

Google Sectera.

I think there are civilian variants. You can't buy the Type I certified units unless you're a government contractor or the government themselves. I have no idea whether or not the civilian variants have any sort of backdooring.
Posts: 472
Joined: Tue Jan 08, 2008 12:43 am
Location: Owego, NY USA

Re: Encrypt cell phones calls!!!!

by Ramjet1 on Tue Feb 08, 2011 1:20 am

There is no encryption technology available to the general population that will prevent government / law enforcement from being able to read the data stream. Depending on who wants to read it, it's trivial.
Posts: 70
Joined: Sun Jan 23, 2011 10:52 am

Re: Encrypt cell phones calls!!!!

by gwenhastings on Mon Mar 21, 2011 5:10 pm

not quite so fast.. there is cryptophone also http://www.cryptophone.de/ and the unit I was just recommended to is this one...http://www.cryptophone.de/en/products/mobile/cp400/..

some other products will shake out I suspect...

Posts: 26
Joined: Sat Dec 05, 2009 3:14 pm

Re: Encrypt cell phones calls!!!!

by Syn7 on Fri Dec 28, 2012 6:52 am

It's voip. Not quite the same as encrypting a cell phone. I'm sure it works fine tho.
Posts: 152
Joined: Sat Nov 17, 2012 3:06 am

Re: Encrypt cell phones calls!!!!

by adafruit_support_mike on Fri Jun 14, 2013 11:40 pm

Before everyone gets too excited about encryption, I'd suggest you look up civilian cryptography guru Bruce Schneier and read what he has to say on the subject.

Short version: there was a time in the early days of civilian cryptography when people believed encryption was a 'magic security dust' (his term) that people could sprinkle on problems and make the bad stuff go away. As civilian experts spent more time exploring detailed real-world problems, they found that security protocols are even more important. It doesn't matter how good your lock is if your bank vault has a big plate glass window.

Real security is a hard problem, and many years of expert research have shown there's no product you can buy that will make it stop being a hard problem.

WRT cell phone encryption, the first and most obvious problem is, "how do you plan to transfer the keys that allow the people at the other end to decrypt your call?" An unencrypted phone call is probably not the best option. On another track, if the keys live in hardware, anyone who gets physical access to any phone you can call has just broken your security.

WRT the recent disclosures about PRISM, encrypting the conversation is irrelevant. The NSA has been collecting metadata about the calls.. which numbers you called, how long each call lasted, when you made the calls, where you were when you made each call, etc. Your actual conversation could be in a pdigin of Navajo, Teochow, and Basque for all it matters. The stuff the NSA has collected is inherent in making the phone system operate.
When you void a product warranty, you give up your right to sue the manufacturer if something goes wrong and accept full responsibility for whatever happens next. And then you truly own the product.

Posts: 36041
Joined: Thu Feb 11, 2010 2:51 pm

Please be positive and constructive with your questions and comments.