At 10:30 PM 8/15/95 -0400, Dave Emery wrote:
I reiterate my suggestion of a few months ago that one could quite easily adapt the firmware on one of the new simultanious data and digital voice on the same phone line modems to incorperate encryption, and quite possibly encryption/key exhange interoperable with some mode of PGPphone. Doing this would relieve one of the need to develop or manufacture any hardware at all - all that would be required to have a portable "bump in the cord" encrypter widely available for a low price would be creating a new version of the downloadable flash ROM image that did encryption and PGPphone key exchange.
Most modems I've seen only have one set of audio interfaces, and a bump-in-the-cord phone needs two (one for the voice side, one for the modem line side.) (Having two jacks doesn't count.) So you'd need at least two modems, one straight and one re-educated, and you'd probably need lots more flash ROM than the average modem has. On the other hand, laptops are increasingly getting multimedia capabilities like built-in sound cards, and if there's a microphone jack you're in business (uh, well, for $3K or so) Or a cheaper laptop with two PCMCIA modems, if you can re-educate one, which also lets you move the non-audio parts of your secure phone program into the PC. Of course, if you want long conversations from the airport, you'll still need to find a payphone within 4-6 feet of an electric socket and not located under a MegaMuzak speaker, but that's easier than trying to balance a TI Silent 700 under similar conditions :-) #--- # Thanks; Bill # Bill Stewart, Freelance Information Architect, stewarts@ix.netcom.com # Phone +1-510-247-0664 Pager/Voicemail 1-408-787-1281 #--- "The fat man rocks out Hinges fall off Heaven's door "Come on in," says Bill" Wavy Gravy's haiku for Jerry
At 10:30 PM 8/15/95 -0400, Dave Emery wrote:
I reiterate my suggestion of a few months ago that one could quite easily adapt the firmware on one of the new simultanious data and digital voice on the same phone line modems to incorperate encryption, and quite possibly encryption/key exhange interoperable with some mode of PGPphone.
Most modems I've seen only have one set of audio interfaces, and a bump-in-the-cord phone needs two (one for the voice side, one for the modem line side.) (Having two jacks doesn't count.) So you'd need at least two modems, one straight and one re-educated, and you'd probably need lots more flash ROM than the average modem has.
The kind of modem I was refering to is designed to supply a digital voice connection interleaved with 28.8 kb V.34 high speed data over a common modem connection. As such it has an extra audio A/D and D/A and line interface; in fact some of these modems actually have a full telco CO type phone line interface so one can plug in a regular vanilla phone and talk full duplex over the digital path just as on an analog phone line. They are already trully bump-in-the-cord devices. These modems are a new product, just being introduced, and are apparently aimed at the service desk/tech support market where they supply the capability for someone diagnosing a problem to have the customer's screen display on their system and access their keyboard while talking to the customer about what is wrong. (As a historical note, I was involved in the development of this technology at Data General in the late 70's using fdm data over voice analog signalling - the reason it didn't catch on was that the modem connection was very slow (300 baud)). There is an effort in the modem industry to standardize the voice compression used and the protocol so such modems will interoperate with those made by other manufacturers - I don't think anybody has addressed encryrption in this protocal (after all, the NSA has kept encryption out of the data side of modems where it would be trivial to implement). As for the ROM size issue - I'm sure if one was expecting to be able to drop in PGPphone code relatively unmodified it would be a problem, but actually implmenting the core encryption and crypto sync stuff would only be a few tens of kb of code at most in a ROM that may well be 512 kb or more now with significant space reserved for expansion and bug fixes and support of older modem protocols. Dave Emery die@die.com
participants (2)
-
Bill Stewart -
Dave Emery