You can't.

The Newluminati reptiles can take your cryptoez by thought any time they want.

Nah I'm only kidding. Just shell out for a few metres of this stuff:

http://www.noiseaddicts.com/2008/11/most-expensive-speaker-cable-world-audioquest-audiophile/

And place your speakers on the OUTSIDE of your house.

Works a charm.