[averagewall]

Strong encryption is another thing that sci-fi authors seem to miss. For example 1998's Moonwar has people sneaking communications on laser beams instead of radio waves because spies won't be able to eavesdrop on the straight-line laser without physically going to its location. That, despite the internet already using encryption for financial transactions in real life.

[niftich]

Yeah but how do you do key distribution and management? The physical security and "forward secrecy" (in the loose sense) afforded by an ephemeral transmission that can only be received in a fixed location is non-negligible [1].

[1] http://www.gdsatcom.com/email/3-22-11.htm

[donavanm]

Its not about encryption, and real world concerns are echoed there. Radio (or other broadcast) gives up lots of signal intelligence; times, location, correlation with other events etc. A tightly collimeted/focused media (like laser) reduces those risks while having other benefits like a reciever detecting interception via attentuation.

[kalleboo]

I'm not sure this is what the authors had in mind, but you can imagine a post-encryption future (quantum computing or whatever lies beyond)