I’ll be skipping over the WWI history in these two chapters to highlight what I think are the note worthy parts. Let’s begin:
First, an interesting distinction is made between cryptography and cryptanalysis: “Cryptanalysis can alter the status quo. Cryptography can at best conserve it. Cryptanalysis can bring countries to war, engender naval battles and win them […] Cryptanalysis hammers upon the real world. Cryptography does not.” (page 298).
Strong statement. I fully accepted it at first, but on second thought, cryptography is not given its due. Cryptography is defence, cryptanalysis is offence. While offence is flashy and cool, you still need a solid defence for it to matter. You almost got me here David.
What’s additionally interesting is that in spite of the Ally superiority in cryptology over the Central Powers, the Germans still dominated for most of the war. So although cryptanalysis can “engender naval battles and win them”, it is lacking in its power to win wars.
Second, here is an unintuitive piece of advice “If you do not have time to encipher entirely, transmit in clear” (page 312). This was among the instructions to French soldiers. Cryptography is primarily about secrecy, but don’t focus on that too much, else you might loose it entirely. Better to have one battle plan leaked to the enemy than your whole war strategy. Repeat after me: No encryption is better than weak encryption. Notice how the previous phrase can be read in two ways, yet they still mean the same thing.
Finally, a lot of technological advances are because of war. War means more money because government is willing to spend. War means more is at stake because we may die if we are not better than the “enemy”. The field of cryptology is not exempt from this. Here is an excerpt from page 348: “The First World War marks the great turning point in the history of cryptology. Before, it was a small field; afterwards, it was big. […] The direct cause of this development was the enormous increase in radio communications”. Without the two world wars, I wonder where the technology field would be right now.