World wars, cyphers and subs

War grips the globe, twice. Technology pushes forward, including the specialized calculating machines to encrypt messages on the one hand, and break the encryption of the enemy on the other.

Here’s an article about the submarines of world war II.

Submarine Warfare Played Major Role in World War II Victory

Here are a couple of articles about how Poland broke the German’s secret codes.

Poland's overlooked Enigma codebreakers

How Three Poznan University Students Broke the German Enigma Code and Shortened World War Two