Here is an interesting link. It is a simulation of the famous Enigma Machine from WWII. You can alter the settings and input a string of text to be encoded. The flash simulation will show how the thing works. If you copy & paste the encrypted string back into the input, it will decrypt it.  Not surprisingly, it doesn’t accept number or space characters.

Ever seen pictures of an uncontained jet engine failure?  It would be interesting useful to know if the frags had enough energy left over to penetrate the cabin.