If your house is alarmed, I strongly suggest a Key Lock Box.  They allow you to have a key outside and it is secure.  Install near a light source, and preferably under cover.  Note I have run one of these over with a car, and also cut one open with a grinder.  They are very strong, and in any case it would be easier for a would be burlgar to smash a window rather than spend hours trying to get one of these open.

They can also be used in a commercial setting, say a key to a certain room that needs to be handy, but not available to anyone just walking past.

Please see video below…