Subject: Any cypherpunks building encrypted phone? Hello everyone! I'd like to know if anyone on the list has made any attempt to construct a true encrypted phone, something at the level of the AT&T DES phone. I think that it ought not to be too difficult to build a couple, using existing modems and basic hardware design. If all the commercial phones are going to be Clipper-based, we'll have to build the real ones ourselves. Lady Ada, Queen of Engines
Subject: Any cypherpunks building encrypted phone?
Hello everyone! I'd like to know if anyone on the list has made any attempt to construct a true encrypted phone, something at the level of the AT&T DES phone. I think that it ought not to be too difficult to build a couple, using existing modems and basic hardware design. If all the commercial phones are going to be Clipper-based, we'll have to build the real ones ourselves.
Lady Ada, Queen of Engines
Yes, several such projects are underway. Eric Blossom even showed a PCB of one at a Cypherpunks meeting, using an inexpensive DSP chip. Software-only versions, with some compromises in speech quality probably, are also underway. Phil Zimmermann described his progress at the last Cypherpunks meeting. ("Software-only" can mean using off-the-shelf, widely-available DSP boards like SoundBlasters.) And I know of at least two more such projects. Whether any will materialize is anyone's guess. And various hacks have already been done. NeXT users have had voicemail for years, and certain Macs now offer something similar. Adding encryption is not a huge obstacle. A year ago, several Cypherpunks meeting sites around the U.S. were linked over the Internet using DES encryption. The sound quality was poor, for various reasons, and we turned off the DES in a matter of minutes. Still, an encrypted audio conference call. So such things are possible today. --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."
On Tue, 12 Apr 1994 anonymous@extropia.wimsey.com wrote:
Subject: Any cypherpunks building encrypted phone?
Hello everyone! I'd like to know if anyone on the list has made any attempt to construct a true encrypted phone, something at the level of the AT&T DES phone. I think that it ought not to be too difficult to build a couple, using existing modems and basic hardware design. If all the commercial phones are going to be Clipper-based, we'll have to build the real ones ourselves.
Lady Ada, Queen of Engines
Word has it that Phil Zimmerman, author of PGP, is working on an IBM compatible program to encrypt telephone conversations with PGP, using a high speed modem and a sound card. When I spoke with Phil last (actually, the only time I spoke with him) in February, he advised me that the program was in beta stage, and was currently operational with *no* encryption built in... He indicated that the basic engine (high speed modem and souncard in an IBM compatible) was working "better than [he] expected." I can't wait to see this thing when its finished. Forget clipper-phones, every American will already have everything they need to have their own encrypted phone... Yup, just use that multimedia PC that has been collecting dust except when you pull out the old Encylcopedia CD- Rom!! Evidence, Inc.
Timothy C. May writes:
Yes, several such projects are underway. Eric Blossom even showed a PCB of one at a Cypherpunks meeting, using an inexpensive DSP chip.
So when will the schematics and part numbers be posted for all to see? ;-) -- Steve Davis <strat@cis.ksu.edu> Kansas State University
Steve Davis writes:
Timothy C. May writes:
Yes, several such projects are underway. Eric Blossom even showed a PCB of one at a Cypherpunks meeting, using an inexpensive DSP chip.
So when will the schematics and part numbers be posted for all to see? ;-)
At this moment our primary efforts are on developing a family of extensible protocols for both encryption and voice across point to point links. We indend to use existing standards where ever possible. We are currently planning on building on top of the RFCs for PPP (see RFCs 1549, 1548, and 1334). The basic idea is to add a new Link Control Protocol (or possibly a Network Control Protocol) that will negotiate base and modulus and perform DH key exchange. Some forms of Authentication are already supported by RFCs. We're looking at others. The next layer up will perform an encrypted negotiation (using a fixed algorithm, perhaps Hellman-Pohlig) of the type of encryption to use for the session. This includes algorithm and modes. We are currently looking at 3DES or IDEA in OFB-64 or OFB-8. This gives you a synchronous stream cipher that does not propagate errors. At this point, you have an encrypted tunnel. The next layer up will negotiate the voice protocol, and support for muxing data and voice. On the voice front, we are looking at FED-STD 1015 LPC-10eV55 (2400bps), FED-STD 1016 CELP (4800bps) and a couple of CVSD variants in the 13000 - 28800bps range. There is a MILSPEC for CVSD. CVSD has the advantage of being cheap to compute, but since the data rate is higher, your crypto demands are higher. For those of you unfamiliar with PPP, it provides a very nice framework for negotiating options across both ends. The same automaton can be used for each layer, simplifying matters greatly. I'd welcome any comments or suggestions. I'll probably have a complete draft available in a week or so. Stay tuned for further developments... Eric Blossom
participants (5)
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anonymous＠extropia.wimsey.com -
Eric Blossom -
Evidence Inc. -
strat＠cis.ksu.edu -
tcmay＠netcom.com