After the invention by Guglielmo Marconi🐱

 The Italian physicist Guglielmo Marconi invented a powerful form of telecommunication, which made the need for secure encryption even more pressing. Marconi's invention tantalised the military, who viewed it with a mixture of desire and trepidation. The tactical advantages of radio are obvious: it allows direct communication between any two points without the need for a wire between the locations. Laying such a wire is often impractical, sometimes impossible. 

 Previously, a naval commander based in port had no way of communicating with his ships, which might disappear for months on end, but radio would allow generals to direct thier campaigns , keeping them in continual contact with battalions, regardless of their movements. All this is made possible by the nature of radio waves, which emanate in all directions, and reach receivers wherever they may be. 

 However, this all-pervasive property of radio is also its greatest weakness, because messages will inevitably reach the enemy as well as the intended recipient. Consequently, reliable encryption became a necessity. If the enemy were going to be able to intercept every radio message, then cryptographers had to find a way of preventing them from deciphering these messages. 

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