Interview with David Kahn
The place: We at India and Mr. David Kahn in New York, over Skype.
The time: 07:30 p.m. our time (India) and10:00 a.m. his time (with Daylight Savings), on March 10th, 2008, Monday.
The subject: Cryptography and its history.
Jason shooting questions, Namrita scribbling down notes.
J: Good morning Mr. David Kahn, how are you today?
DK: Good morning, I am fine. I hope you are as well.
J: Today we'd like to interview about the history of cryptography. You are a specialist in this area. So shall we start?
DK: Yes, if you will.
J: Ok, our first question would be. What was it about cryptography that really caught your eye in the beginning?
DK: Actually I began when I read a book in the Great Neck library. The author was Fletcher Pratt and the title of the book was Secret and Urgent and it came out in 1939, but I read it in 1943 and the book was an extremely well written, rather superficial as I now know, history of codes and ciphers and this book was so interesting and the subject fascinated me so much that I became interested in codes and ciphers and in particular in their history and I've been studying it ever since.
J: Alright! So it started quite early dint it sir?
DK: Yes when I was 13.
J: Ok. So the enigma, the enigma machine used by the Germans. It has always been a historical intrigue. Could you tell us about the events that led to its downfall?
DK: Well the enigma, the German enigma machine was bought by the Germans in 1923 I think by the German navy or maybe 25 and put into service at that time. And that was after WWI. And as WWII approached, the British realized that an important aspect of their intelligence would be to obtain as much information as they could about the German Enigma machine and to solve it if they could. Well at the same time the Poles, who were squeezed between the Soviet Union and Nazi Germany were obtaining as much information as they could about these 2 countries and in particular they began attacking the German enigma machine. It was used at first by the army and later by the navy and the poles attacked this machine using mathematical techniques and using 3 brilliant mathematicians, the most brilliant of whom was a man named Marian Rejewski and with their work , their mathematical knowledge in particular, they were able to solve the enigma machine and discover how to solve it. Then as the Germans kept improving this machine, the Poles realized that they were not able to keep up with it. They dint have the resources and the man power and the money and the economic productivity to produce the devices need keep up with this electromechanical cipher machine. So in July of 1939, they revealed their secrets to the French and to the English who then kind of took on the solution and from that point on it grew until during WWII where the British were able to keep up as much as possible with the German Enigma cipher machine messages.
J: Ok that was quite interesting. Could you tell us a little about your latest work on the history of American intelligence in World War II?
DK: That work is still a work in progress. I am trying to find out what role intelligence played in WWII on the American side. It is an interesting subject and there are a great variety of kinds of intelligence. I mean its not only code breaking, that was probably the most significant. But there was also aeriel reconnaissance, there was actually ranging of artillery. There's such simple work as patrols and all of that . So I am working away on that right now, it is about half done. The way I am doing it is going down to the national archives , trying to find cases in which the documentary record shows that intelligence played a role and obtaining that information and then writing it up. Let me just say one point, however. That interesting as intelligence was, I do not say it because I don't think is true, but intelligence, allied intelligence won World War II, it helped them. But the allies won WWII for 2 reasons. First of all, Russian man power, the Russians had so many people and the land was so big that the Germans could never conquer it. And number two, Americans industrial might. The Americans had factories that were never bombed and so could out produce the Germans. So those were the reasons we won the WWII- American industrial right and Soviet man power. But what intelligence did I felt was manage to facilitate this work and bring the war to a shorter conclusion. That was the real contribution of intelligence in WWII.
J: We see your history in the making I guess. It is said that a wise man always learns from the mistakes of others. If there is one lesson modern cryptographers can learn from the history of cryptography, what would that be?
DK: That's a good question. I don't know, but I will only say that thus far it has been the case that for every new code system or cryptographic system that has been invented there had been a new method of solution. But nowadays with new types of code systems which seem to be mathematically unbreakable, I don't know whats going to happen in the future. Maybe that codes are going to be broken not by cryptanalysis, but by stealing the keys or intercepting some of the keying methods. At present, to me anyhow, because I don't have any access to what is going on in the cipher bureaus of the world, I think that's the way it looks right now. That there seems to be a case finally, in which the code makers have an advantage over the code breakers and so far there doesn't seem to be any indication that the code breakers are going to be able to get ahead as they have done in the past.
J: I guess we could have a secure world after that. What is your take on personal privacy versus national security?
DK: I am in favor of personal privacy. There of course has to be a balance but I think the United States Government, the Bush administration has perhaps gone a little bit too far and it seems to me, that if we continue giving up our freedom, we lose what we are supposed to be fighting for. So I am in favor of a balance strongly for personal security with obviously some cases in which national security plays a role but those cases must be weighed on an individual basis. There are too many to discuss right now.