In 1895, the first wireless radio was invented, giving rise to a new age in cryptography. Radio provided military troops in World War I with much greater flexibility by eliminating the need to run wires between camps and headquarters. However radio is public; anyone can intercept the signals and look at them to his or her hearts content. No longer was it necessary to tap a wire directly; someone could simply put up a radio receiver and half the work was done. As a result, cryptographers of World War I had to invent stronger systems of encryption to withstand an enemy’s best attack when a greater amount of encoded text is available.

In World War I, the French were the first ones to be prepared for the impact of radio on the breaking of enemy codes. By the time war broke out, France had established bases and outposts for the sole purpose of intercepting German communications. These outposts had been intercepting German messages during the peace and continued to do so into the war. In total, it is estimated that the French intercepted 100 million words of German communications.

Although they couldn’t decrypt them at first, the French stored all German transmission. Later on, when decryption of messages became a reality, the French were able decrypt the earlier messages and gain insight on what the Germans were thinking early in the war.

Early in the war the French tackled the problem of where German troops were located in a very creative way. Although they had no idea what German messages said, they recorded with diligence the strength of signal, the volume of messages, call signs, as well as any clear non-encrypted text that slipped through to determine the composition of the German forces. Their analysis resulted in a diagram of major German bases within the two weeks of the outbreak of war, which was mostly accurate.