There is a rear locking rack box, the only one I've ever seen is by Sunlite, but it's not really what I would consider "high security". It's made of plastic, but it does take a key, and will deter the "casual theft". I actually know this company well, and their products are available at just about every bike shop in the US, as well as many places online. Shouldn't be hard to find.

There is a rear locking rack box, the only one I've ever seen is by Sunlite, but it's not really what I would consider "high security". It's made of plastic, but it does take a key, and will deter the "casual theft". I actually know this company well, and their products are available at just about every bike shop in the US, as well as many places online. Shouldn't be hard to find.