No Subject

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

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

> 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.