It almost esacped me: Sound cards and HF radios work together to do a variety of digital comms ... like RTTY and PSK31 (nice for weak signal keyboard to keyboard work). Through the miracle of a bit of bit mixing magic (like DES or better yet AES) out would come a soup that’d be tough to make sense of ...
PSK31 might be best of all.
DES and AES are crackable via brute force (lodestone or distributive computer network). See www.distributed.net for an example of distributed computer network cracking. Pretty Good Privacy (PGP) with 1024 bit encryption is (so far) unbreakable. When PGP is used with Private Idaho mixmaster remailers it becomes impossible to trace the sender or the recipient. Any email hence becomes anonymous and encrypted.
- Traveler