[Roboprog]

I think the "slowness" aspect of "do it twice" is a given, making the best of a bad situation. Clearly, the people who want languages or hardware to do this "right" have a better solution, but if you have to get by with C on existing hardware, it would seem that an option in a library to select further security at less speed is reasonable. Of course assuming said option runs code that won't be optimized away.