The feds aren't going to like it when you hook up your Vectrotel X8, a normal-looking GSM cellphone that has some serious 128-bit encryption inside. It has the usual features of a run-of-the-mill handset, such as a Bluetooth and USB connectivity, 1.3-megapixel camera, a 320x240 display, and it works like an everyday cellphone, too.
Things get really different when you want to encrypt phone calls, where the catch is that you'll need two of these phones talking to each other for the encryption to work. After a 10- to 30-second handshaking process, the two phones share a unique 128-bit key that uses something called a 1024-bit Diffie-Hellman shared secret exchange. The two phones use this particular key just once and then delete it after the call.
Can the encryption be broken? Vectrotel says yes, it is possible to decrypt a phone call, but it will take you about a trillion years. The company didn't say how much the phone will cost but if you have some secret stuff to talk about, it just might be worth it.