Spirits and Passwords, magic plus tech FTW Options

[Riley37]

Having secure communications, and eavesdropping on opponent's communications, is a good thing in black-trenchcoat SR campaigns.
My PC group has largely relied on Mind Net, but it has limited range, it requires sustaining focus or sustaining penalties (or tasking a Spirit of Man to cast and sustain it), and it's not so good for transmitting detailed tactical maps and other high-density information.
Radio doesn't have these limitations but in SR4, decryption is easy.

So combine magic and tech. Set up a comm channel, and use a spirit to communicate your key to the other person or people. Low-end: use a watcher spirit. High-end: use a spirit with metaplanar shortcut. Darn hard to intercept!