I haven't seen this on the cypherpunk list so I thought I would forward it as an FYI. Interesting that source code is available!

Subject: FWD: Free secure Internet voice communication From: John Walker <kelvin@fourmilab.ch> Subject: Free secure Internet voice communication

I've just released to the public domain Release 5 of Speak Freely for Windows and its Unix counterpart, Netfone for Sun and Silicon Graphics workstations. Assuming you have a fast enough connection to the Internet (with reasonably consistent packet delivery time) and/or a fast enough CPU to perform audio compression in real time, you can talk to anybody on Earth connected to the Internet who's also running the program. The Windows and Unix versions have entirely different user interfaces, but can intercommunicate. Complete source code is available.

For communications security, IDEA, DES (less initial and final permutations), and one-time pad (re-used for each sound packet) encryption are available. The intensely paranoid can enable any combination of these. The documentation explains how to use PGP to securely exchange session keys before a conversation; an automatic session key generator is provided. DES is included for commercial users who don't have a license to use the IDEA patent. One-time pad encryption is for those with machines too slow to run IDEA or DES in real time.

I didn't include a public key mechanism because I wanted to avoid all the confusion. If somebody wants to navigate the narrow strait between the RSA patent Scylla and Charybdis of export controls, the programming work to implement public keys is straightforward and the source code is yours to hack.

For further information, see:

http://www.fourmilab.ch/netfone/windows/speak_freely.html

which describes the Windows version in detail and contains pointers to the Sun and SGI editions, as well as links to download source code and a ready-to-run executable for Windows. You can also obtain the program by anonymous binary FTP:

Unix source code: ftp://ftp.fourmilab.ch/pub/kelvin/netfone/netfone5.tar.gz

Windows executable: ftp://ftp.fourmilab.ch/pub/kelvin/netfone/windows/speakfb.zip

Windows source code (for Visual C 1.5): ftp://ftp.fourmilab.ch/pub/kelvin/netfone/windows/speakfs.zip

Have Fun! Regards, Mark Hittinger Internet Manager WinNET Communications, Inc. bugs@win.net bugs@ritz.mordor.com