ScanRiverside.com

I know encrypted transmissions cannot be received on a scanner, but I'm wondering how it would sound from a user perspective (on an actual police radio). If anyone has a recording, that would be nice.

Digital will sound the same non-enc or encrypted.
Analogue can degrade in quality.

Here is a good site with audio samples of recovered encrypted voice
http://groups.yahoo.com/group/voice_enc ... ing/files/

Back before the ECPA of 1986 made them illegal, devices to decode encrypted transmissions were a common scanner add on gadget. Grove used to make them, as well as some other companies. I'm sure those types of encryption are ancient history now, though. I have heard the "soap bubbles" encryption on some local security company freqs before, though, so someone must still use the low tech stuff.

brandon wrote:Digital will sound the same non-enc or encrypted.
Analogue can degrade in quality.

Here is a good site with audio samples of recovered encrypted voice
http://groups.yahoo.com/group/voice_enc ... ing/files/

No can do. I have to log on, and I don't have a Yahoo account.

It sounds the same as any other transmission in P25. Most of the older crypto schemes like DES-XL and DVP that use 25khz bandwidth are no longer legal under the new narrowbanding rules, so most all of the newer encrypted systems use DES-OFB, or AES algorithms. The "donald duck" sounding voice inversion systems are really "scrambling" (as opposed to encryption) and can still be ran on 12.5 khz channels in narrow FM, but all the serious encryption is going to be digital, in such case the recovered audio sounds identical to clear digital audio.

N6AJB wrote:It sounds the same as any other transmission in P25. Most of the older crypto schemes like DES-XL and DVP that use 25khz bandwidth are no longer legal under the new narrowbanding rules, so most all of the newer encrypted systems use DES-OFB, or AES algorithms. The "donald duck" sounding voice inversion systems are really "scrambling" (as opposed to encryption) and can still be ran on 12.5 khz channels in narrow FM, but all the serious encryption is going to be digital, in such case the recovered audio sounds identical to clear digital audio.

By the way, did anyone ever notice how whenever there is an encrypted transmission on COPS, you can hear a buzz and see "Encrypted transmission" in the caption?

By the way, did anyone ever notice how whenever there is an encrypted transmission on COPS, you can hear a buzz and see "Encrypted transmission" in the caption?

~The screen just blinks fast, twice.

N6AJB wrote:

By the way, did anyone ever notice how whenever there is an encrypted transmission on COPS, you can hear a buzz and see "Encrypted transmission" in the caption?

~The screen just blinks fast, twice.

I actually never noticed that. I always heard the buzzing and saw the caption.