but they need some pretty good chip to encrypt realtime audio i geuss;)
Yeah, probably an integrated system design to make the encryption on the fly would be something very specific and not easy to get in the market. Or at least cheap to buy.
Or maybe if the encryption algorithm was programed directly in an assembly language for maximum eficiency. A simple MIPS processor would do the trick, lol.
One other thing. Encryption on the fly can't be very secure. A good encryption algorithm needs "space to work", that is, it need to have a piece of data and apply various operations in it to be secure. If an algorithm has just a limited peice of information like in this case one second of the audio, then even with a password the encryption the code would be easy to crack by brute force.
On the other hand, if instep of a second the audio would be one minute, then there would be space to apply a more complex encryption algorithm way harder to decode.
But well if they exist there must be a possibility to do this, even with a chat program, lol.