Hi Bill, Bill Stewart wrote:
Not per se, though there _is_ still one major restriction - the Defense Department gets a crack at patent applications, so if you try to patent a crypto algorithm or crypto phone, they can seize and classify your patent application and working materials, using the excuse of "national security".
I suppose we need more altruistic gestures placing good stuff into the public domain.
Sure there are - my $150 cordless phone uses spread-spectrum, partly for better sound quality, partly for better privacy, and partly because it's simpler than picking individual channels.
The security is only between the handset and the base unit. Once the signal hits the POTS it's the same old story - open line. ALSO - the channels and the hopping sequence used in the "spread-spectrum" systems are predefined. Kind of like making a stream cipher with a very short bitstream you got from the government printing orifice. Using any other sequence is a crime. The real purpose of the spread spectrum phones is to allow increased signal levels. The security is not robust. Try this one: Not particularly original - I would guess that Tim's 3DES phone is something like this. Wal Mart Plastics for the housing ( ever tooled plastics? $$$ ) Custom board Dedicated DSP for voice compression/decompression Modem chipset for POTS connect ( direct or ISP ) Fast microP for encryption/protocol Any encryption algorithm you desire Software Developer's Kit ( roll your own algorithm ) This will work very nicely at home or with any cell phone that has a modem port. It's really nothing but a dedicated version of a PC based PGP phone. It's just smaller and cheaper than a PC and has no MS DLLs on it. Regards, Mike