> if military tech were developed with "Open Hardware" goals in mindNot going to happen. Military hardware is (most of the time) cutting-edge technology. If we are talking about a fighter plane, most of its components have to exhibit high performance overall -- and in small package. The abilities of the plane hinge on every component and their co-operation as well; the weakest link is the limiting factor.
Each military technology has two aspects: instances of use (for lack of better word), and capability.
Consider encryption for a moment: an algorithm of any size and complexity is driven by a small key (a bunch of bytes). The small secret part (key) is enough to to keep each use instance (each encoded text) safe.
However, in case of military hardware, the capability itself is of paramount importance as well. You can't focus all the aspects of fighter plane in one `key' piece; each component has to provide some aspect of the capability -- and withstand results of use of other components, such as heat, acceleration, vibration etc. Since no `key' is possible to hardware, you have to guard whatever else is there to guard -- and that, unfortunately, is most of the pieces.
Nb., a lot of military standards [1] are commercially-accessible, to help build a healthy ecosystem of suppliers. But those are not cuttind-edge stuff; I don't think even the formula for SR-71's `JP-7' fuel was accessible during operational use of the plane...
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[1] http://en.wikipedia.org/wiki/U.S._military_standard