On Tue, 19 May 2009 21:36:36 -0400, "Woodrick, Ed" <ewoodr...@ed-com.com> said: > Interesting, I see that Pactor III protocol is published at > http://www.arrl.org/FandES/field/regulations/techchar/PACTOR-III.html
Ahh they finally gave in and realized it was illegal to keep it proprietary, I see. Sorry, I became disinterested late last year or before. I guess they finally did the right thing. > I believe that as with D-STAR, portions of the signal might be > proprietary, but the envelope protocol is published and specifically the > station identification is documented. The encoding portion of Pactor III > could be considered similar to that of the AMBE vocoder. Is there any practical difference between a vocoder and a proprietary encryption algorithm to the receiving station? > As to SSL encryption, I believe that the response may be similar to that > of the High Speed Data Committee on the 802.11abc protocols. The word > encryption does not appear in Part 97, but the word obscure does. Part > 97.309(b) specifies what is permitted and it can be indeed interpreted in > a number of ways. Probably the most interesting is 97.309(b)(3) that > indicates that if asked, the original information must be provided. This > would indicate to some that encryption is actually expected. That was my conclusion in the sidebar also. If you could provide anyone listening with a way to "decrypt" the data -- you stood a fighting chance, but it's not black and white in the U.S. regulations. Now apply that tidbit to the above "CODEC". We can't "decrypt" D-STAR signals without a proprietary chip from a manufacturer. While I'm the first to defend the manufacturer in this regard (PhD's in math aren't cheap, and the people who earned them also have to feed their families), it's just an interesting corrolary when you look at it this way, isn't it? Go the other direction -- someone bent on "encrypting" something could call it their proprietary "encoding" and sell a chip to do it marketed as a CODEC and get away with "obscuring" their transmissions... they could have "order delays", "problems with upstream vendors", "out of stock" and all sorts of made-up problems for ... who knows? I think at least a year or two, where they and their buddies could be the only folks who could copy what they were transmitting. (Well, NSA and other uber-smart folks might listen in and figure out a simple scheme, but we'll leave them out of this discussion. Someone's ALWAYS listening... no doubt about that.) So... then they come out with a "beta test" of "Version 2"... start shipping Version 1 to everyone, and limit the beta test to the original group... and that lasts a year, or they announce "setbacks" and it becomes two... then they release it again with delays, problems. If the first one really wasn't all that useful to anyone, by now they've fallen off of all but the zealouts radar... so to speak. Anyway, it's a completely fictitious story made up to show how "encryption" of Amateur transmissions could be done. Frankly, so few people monitor odd-ball simplex channels, or even less listened to... UHF or higher SSB... that it's really not that hard to have a "semi-private" conversation on the ham bands... heck, if you can get between or behind me and the guys across town I'm talking on 10 GHz to (yes, I do that for contests, but it's generally a pain any other time)... we'd probably be happy to hear you and have you join in. (And yes, I've had round-table ragchews on 10 GHz... if everyone's in the right place and the dishes are pointed right!) The discussion, of course, is all in good fun. But I ask: What's the EFFECTIVE difference between something we call a CODEC, and something that does "encryption" of a data stream. I contend: Not much. And the regulations are WAY behind on this one... maybe rightly so... how would they ever define it. How would you prove the intent was to "obscure"? (Unless they're dumb enough to talk about their intent on-air or off, I suppose.) It's interesting, isn't it? Pretty "deep" topic for a hobby to deal with. In my professional work, we see trade secrets for CODEC operation all the time. As it spills over into the Amateur airwaves, it's quite entertaining to see how we're going to deal with all of it. Nate WY0X p.s. I'm NOT saying the Pactor III folks were trying to "encrypt", by the way. But it's highly convenient that it took quite a while for a fully-developed specification to hit the web/public eye when the original "modems" were over $1000. Quite a lot of motivation as this technology gets more complex for the manufacturer to hold on to "secrets" about the operation of any said particular digital system until their development costs and a little profit can be gained. Again, not accusing them of doing that... just saying it'd be real easy to make that logical jump mentally. p.p.s. I'm also NOT saying D-STAR is encrypted. There are examples of decoding the audio from "any" radio already... but none that don't require the AMBE chipset from DVSI. -- Nate Duehr n...@natetech.com
