[FedCom] ProVoice on Fed Channels?

[Jeff Kenyon]

ALso, on another note DES is used in other applications other then radio
coms by the federal government.





On Tue, 25 Apr 2006 Signal500 at aol.com wrote:

> 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
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