I think you're off by a factor of 8.. 8K samples/sec is 8K bytes/second, not 8Kbits/sec If we had universal ISDN at 56kb/s or 64kb/s, encrypted voice using PC-class machines would be trivial. Instead, we have to compress down to a data rate comparable to ~1800 8-bit samples/second (V.32bis speed; modem compression won't do very much -- unless nobody's talking -- as voice samples do *not* compress effectively using compression algorithms optimized for ASCII text). While fiddling with my SoundBlaster and some dialogue sampled from a T.V. program last night, it became clear to me that cutting back to ~4K 4-bit samples/second isn't quite good enough, and the compression in either UNIX compress or PGP isn't really tuned for audio samples. It's not the crypto that's the limiting factor, it's the compression. That's why the CELP technology that Phil Karn and John Gilmore are talking about is so important.. - Bill