RE: Modems that variate speed
Sorry I can't attribute the quote properly; Microsloth Mail strikes again...
[modems that change speed in mid-transmission proposed as a defense against wiretap]
Aaron
This would probably thwart someone trying to tap the data stream in real time, assuming that the speed changes caught the snooper by surprise, but I don't think that real-time data traps are the real problem. Someone who went to the effort of listening in on your transmission would probably record the whole session on tape; then, they could map the speed changes and pick up all the data at their leisure later on. I would speculate that a really good DAT deck could record the modem session well enough to give your opponent all the time he needs to figure out the speed shifts and pick up the data. -Philippe
On Tue, 12 Jul 1994, Philippe Nave wrote:
This would probably thwart someone trying to tap the data stream in real time, assuming that the speed changes caught the snooper by surprise, but I don't think that real-time data traps are the real problem. Someone who went to the effort of listening in on your transmission would probably record the whole session on tape; then, they could map the speed changes and pick up all the data at their leisure later on. I would speculate that a really good DAT deck could record the modem session well enough to give your opponent all the time he needs to figure out the speed shifts and pick up the data.
-Philippe
Then the efforts would be wasted. Hmmm... There has to be a way to keep people from snooping on our lines. I guess PGP and other methods like it will be the only way... Aaron -=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=- -=- YABBS - telnet phred.pc.cc.cmu.edu 8888 -=- -=- -=- =+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
Then the efforts would be wasted. Hmmm... There has to be a way to keep people from snooping on our lines. I guess PGP and other methods like it will be the only way...
Aaron
End-to-end security, such as with ciphers, is infinitely preferable to kludges and half-hearted attempts at security through obscurity such as making modem tapping every so slightly harder than it is now. Tricks like modem speed varying would be cumbersome to implement, would require pre-arrangement of the pattern to be used, etc. Just not very strong. (A bit like frequency-hopping/spread-spectrum, which has aspects of crypto systems, as I'm sure Phil Karn can tell us about. But at best a one-time pad and at worst a weak cipher.) End-to-end encryption is much cleaner, stronger, and allows the public key methods of incalculable importance. --Tim May -- .......................................................................... Timothy C. May | Crypto Anarchy: encryption, digital money, tcmay@netcom.com | anonymous networks, digital pseudonyms, zero 408-688-5409 | knowledge, reputations, information markets, W.A.S.T.E.: Aptos, CA | black markets, collapse of governments. Higher Power: 2^859433 | Public Key: PGP and MailSafe available. "National borders are just speed bumps on the information superhighway."
participants (3)
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Aron Freed -
Philippe Nave -
tcmay＠netcom.com