At 2:10 PM -0500 3/31/03, reusch wrote:


Nosing around on the same site, one finds "How military radio communications are intercepted"

Searching for SINCGARS indicates that all US military radios have
encryption capabilities, which can be turned off.  Several, in use,
key distribution systems are mentioned.  Perhaps these systems or even
encryption, with infrequently changed keys are, as you suggest, too
inconvenient to use under the conditions.  -MFR

There is a lot of material on SINCGARS available on line via Google. This is a low-VHF system used primarily by U.S. ground forces and those who want to talk to them. It offers both frequency hopping and Type-1 encryption (at least the newer models) and can also be used in single channel, unsecured mode to talk to older VHF-FM radios. According to one source, about 164,000 SINCGARS radios have been fielded and all older VRC-12 radios should have been replaced by 2001.

The key management systems (nightmare may be a better term) are described in considerable detail in . It's from 1996 and makes very interesting reading. For example, radios have to have their time set to within 0.4 sec of GMT. It's easy to believe that units switch to un-encrypted modes under the stress of battle.

Even tho the radios seem quite versatile, the usage is extremely hierarchical. News reports have stated that one advance in this war is that the daily "tasking order" can now be distributed electronically. This probably includes all the material needed to set up the SINCGARS (frequency hop list, frequency hopping keys, communications security keys, call sign lists, network IDs, etc.). That may make things a little better than in 1996.

I went to a lecture at MIT by someone for the US Army talking about the "soldier of the future," an integrated body armor/backpack/electronics system. I asked about encryption and he said it was Army doctrine not to use it at the intra-squad level. Key management is one of the issues. That is consistent with the number of SINCGARs radios produced. So there should be plenty of open voice traffic to analyze.

Arnold Reinhold

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