On 22 Nov 1996, Mullen Patrick wrote:

To be honest, I thought he had a good idea. I just wouldn't want to pay $1000 for phone encryption. But, it's rare I have conversations where I need that much security. I'm sure the product is worth it; it's just out of my price range. And probably out of the price range of the average user.

It was a good idea. It just is facing some very hard engineering challenges. Using software based voice encryption products may work for you. By all means, do give them a try. PGPfone has a codec for use with an ISDN or better. If you have such a fast line, the voice quality is fine. Note that a fast IP connection may or may not suffice. Here is why: Other than bandwidth, the other essential property of the link is constant and preferably low delay. I did not mention this in my original tutorial, since this 1. We were assuming use over a regular POTS, which already has fairly constant delay. 2. There is nothing any codec can do to make up for variable delays. The reason is simple. If the delay is not constant, such as if you are sending UDP packets over the Internet new problems arise. One packet may take 50ms and the next packet may take 250ms, if it doesn't just get lost along the way. Packets may also arrive out of sequence. One might think the answer to this is simply a large buffer at the receiving end. Make the buffer large enough, to be reasonably sure that the packets will all be there, say 500ms. Assuming no other delays, that would mean that you have a 1/2 second delay between the person saying a word and you hearing it. Multiply this by two, since the other side would have the same buffer, and you have 1 second delays. Too long for a conversation. And then there is echo cancellation. But I'll spare you this. ;-) --Lucky