[FedCom] ProVoice on Fed Channels?

[Signal500 at aol.com]

lazygranch and group,

All I am saying is what I heard recorded sounds like DVP-XL.  DES-XL does not 
have the first one second sound (called an initialization vector) that is 
heard before the "squelch noise" on lazygranch recordings.  And yes, both DVP and 
DES have the "high pitch wine" ( the end of pseudorandom bit sequence) at the 
end of the transmission.

And for the record, both DES and DVP were developed in the 70's.  DES/DES-XL 
was developed for the US Government for use in the United States only, and 
DVP/DVP-XL was developed for the US Government for global use, even though it did 
not meet US Government encryption guidelines. DVP is Motorola developed 
Digital Voice Privacy algorithm made in the mid-1970's using 32bit key length.  DES 
is Motorola encryption algorithm that meets US Government encryption 
guidelines made in the mid-1970's (56bit DES key). DVP-XL is Motorola proprietary 
encryption algorithm using 32bit key encryption. DVI-XL is a variant of DVP-XL for 
export outside of the US. DES-XL is a Motorola variant of the US Gov't DES 
algorithm. DVP and DES are self-synchronizing modes of operation, coverage range 
is slightly degraded due to Rayleigh fading on radio channel.  DVP-XL, 
DVI-XL, DES-XL use a sync header and periodic sync updates. For operation on fading 
radio channels, this provides encryption coverage range similar to analog 
voice coverage.  DVP-XL, DVI-XL, and DES-XL should provide similar coverage on 
conventional or trunked systems. Since current generation of trunking control 
channels are not encrypted, someone could monitor which talkgroups are active and 
the general level of activity, even though they could not monitor the 
talkgroup conversations on the traffic channels.

Signal500