[Music] like against beginning with your childhood where did it happen what was the life of your family to the intellectual life of your country it starts in Beth Israel Hospital I'll show her second 1945 and my mother in fact told me I was the second of two three and she said I was in born in a hurry and I've been in a hurry ever since she didn't give birth in the cab fortunately but an intern delivered me because the doctor couldn't get there in time my father was in the South Pacific fortunately in Hawaii instead of Okinawa and actually as I as I say that it's something I've gone back into a personal work I've done I feel I had never really thought about what it was like for my mother to be left with a two and a half year old and three months pregnant with me and have a husband get on a troop train and as I really started to think about that not knowing where he was going it really hit me so that's where it started my father was a high school physics teacher at when I was born he was in the Army Signal Corps but he came back that was his career firs his whole life and there was physics was throughout the family my his younger brother by two years taught at Vons High School of Science where I went and in fact was my physics teacher interesting story which I'll leave out for now and there were there were books but it's interesting there wasn't pressure to there wasn't the whole thing we have today like I didn't learn to read till I was in first grade I mean that was standard but I remember my father had jános physics 1898 or something via copyright and I would look in there and I knew it an early age I had to be a scientist you want that story yes I'm in third grade we're doing studying explorers this is New York so studying like Henry Hudson and people like that and I desperately wanted to be an explorer but I knew that I had to be a scientist I don't know how I knew but I knew idea of being an engineer or computer scientist didn't exist in my mind and but my wife has pointed out interestingly Dorothy that I did become an explorer both in my technical work like public key cryptography the award which gave rise to this interview I went places where no one else went in fact what people told me not to go and then in my personal act the same thing although my wife was my guide on that one we'll get there we'll get there but I still want the child where's the child reading oh but there's another thing about the child yes he felt friendless at age seven I mean when I was a little kid up through age four and a half we looked in a neighborhood that was 99% Jewish the Bronx where I grew up was totally balkanized but I never got declined but when I was four and a half st. Patrick's Day 1950 we moved to the West Bronx my parents bought a house to family house and they never would have moved to an Irish Catholic neighborhood in those days and in that environment but all the kids my age on the block were Irish Catholic and so I was I felt ostracized I mean all kids ostracized to some extent the matically but for me it was the I was a Christ killer I was a dirty Jew I'm going to play with the kids too but you know everyone swallow that would come out and but even when I went to the public school because all the Catholic kids went to the parochial school but even when I went to public school which was almost entirely Jewish even there after a while I was awed and I felt friendless and thought about hmm I think I was probably sensitive I also think I really was always drawn to the feminine side of life when the other boys would steal the girl recess the other boys would steal the girls ball and you know keep it away from them and taunt them I would try to help the girls get it back which of course endeared me to the other little book no wonder I was friendless but I always loved I was with girls and this was pre sexual obviously I mean at age seven or eight there's just something about them that I was drawn to and still I'm drawn to the feminine side maybe empathy is one of the elements I think empathy is part of it and having grown up being ostracized relationship is really important to me in fact it's been interesting Dorothy pointed out and I also realized that the friendless kid has grown up to have a huge number of friends and people talk about how friend I am I'm either but I think it's because I had to learn how to make friends how much would the authorization might have been also that you were what's now called the nerd or I'm not getting that but nobody very interested in reading to be very interested in major scientific issues probably some of that Revenge of the Nerds Here I am probably some of that and I don't know it was actually a gift I mean at the time I would have given anything to be popular to be like the other kids but I look at it now who'd want to be like everybody else especially when being so different has taken me such interesting places both professionally and in my relationship with my wife and the work I do sometimes I'm not saying it happened in your cake there's a teacher who either protects or inspires along the way did you have anything about either in the younger age or later on in high school mentors people adults who you could communicate with well teachers always liked me I mean I was a good kid and I was somewhat of a teacher's pet which probably was another reason that I felt friendless I was interested in following the rules so certainly I remember my teachers and you know like fourth grade mrs. Donovan there's actually fourth and fifth grade not too much six that junior high school there was Miss blank my math teacher really took me under her wing and my uncle when he taught physics helped me with some some things and took a real interest he died recently at age 106 just months ago I loved it because he he taught he had several Nobel laureates in physics having taught at Bronstein but he always called me his best physics student now I'm not saying that was true no no I said but but I want that he said that and that's how I knew that he was still coaching about six or nine months ago when I called him and he said oh my best my best student ever and I knew that I knew that he knew who I was because he doesn't always know now when you've got the broad science which is itself a selective universe of nerds is an overused word but people interested in science were you less friendless I mean was that product beginning to find colleagues with whom he could share ideas yeah and actually looking back even in elementary school I wasn't friendless Tom bearson who was a good friend of mine now he it's really funny

were both married to Dorothy's which is an unusual name for our generation he is prominent in cybersecurity he was the first fellow of the IAC are the Cryptologic Research Association he was a friend of mine starting in fourth grade I had other friends too so maybe I was just overly hard on myself but every every step I went to junior high school and there were new kids and some of the old kids came with me but new kids came in too and I could lose some of the take what I felt rightly or wrongly was the taint of being Marti Hellman from elementary school and high school even more was the real change was in college when I went to NYU which is an interesting story I would have gone to City College because in New York in those days City College was free free and college within the Jewish immigrant culture that I grew up and even though my parents were born here because they stayed in the Bronx instead of moving to the suburbs like most of my aunts and uncles and my father there wasn't a lot of money with my father being a teacher college was not about the parties and football games it was about getting an education so you could get ahead my father went to City College his younger brother my uncle who taught me physics went to City College almost all my aunts and uncles went to one of the city colleges and I would have gone there to accept NYU offered me a full tuition scholarship and I could walk to NYU from my home and so I say 30 cents carfare every day these things like the resume I think and college was the thing that really changed there was I had my first serious girlfriend and she was really popular she was a sophomore she was two and a half years older than me and she ran for was called the University Heights campus which no longer pendant and when he no longer owns she ran from she was one of the four contestants from his Heights and this is not how I thought of myself and she picked me out I mean it was really funny I mean which would she do who would me but it helped change my self-image which had been changing all along but that that was really key but looking back like I was talking to one of the girls and obviously now women who I went to junior high in high school with and it's funny she remembers me I took her sailing on a small sailboat in spite of the lack of money which was interesting I took her sailing out on a Long Island Sound and when I was talking with her and going over things like this she says oh no the way she remembered me is on the boat you know as I put it she didn't use these exact words but heroic pose number three you know on the front of the boat getting ready more yeah oh yeah I was probably 17 at the time I think like that what was your mentor oh all my degrees are in electrical engineering when did that notion this is what I want to do yeah let's see I switched from physics to optical engineering probably my junior senior of high school I became a ham radio operator you know you see the stereo or ham radio in those days that got people into these things now it's more computers and that's when I that whole idea opened up to me and I really loved Electrical Engineering what does that thank you you're thinking about a career for civil by the time you're and then why you an electrical engineering what were you expecting of your career of course many things happen to it what are you expect such a good question it reminds me I remember sitting in probably my junior or senior year of college and I'm in some class looking like 40 other students all going to be electrical engineers and I know this is just one of many universities and colleges across the country across the world and I went what are all these people going to do when they get out because the only thing I could think of electrical engineers doing at that point was designing transmitters and receivers which is what I did as a ham radio operator right and I never thought of things like public key cryptography the internet didn't exist I also didn't think of like the summer jobs I had one of them was in microwave plumbing 1965 before my senior year of college I worked out at this place that was building fair components for phased array radars which were being used to track missiles never thought of stuff like that I mean it could very close to the stuff that I worked on as a ham and then the next year I just between my undergraduate and starting at Stanford I worked for Aerospace Corporation in LA El Segundo and there I was making gallium arsenide diodes for marking sunspot activity which whoever thought of that right but the really interesting one is the summer after that the summer of 1967 I got a job at TRW systems and I think I might have known it was in the weapon systems effectiveness department but I think don't even think I knew that and of course it's all classified work when I get there I find out I'm flying warheads in on the Soviet Union on a computer to try to maximize our effectiveness affect the beyond being able to kill people if a nuclear war comes about it bothered me a little bit but I I did the work my officemate and I used to joke if we had a good idea we might have might result in another ten mega death which was boring ourselves out of proportion I mean we we were working on just such a little weird too small cogs in this thing but and I've used that in some talks that given now that I work on trying to avoid nuclear war I sometimes start out by saying you know I wasn't always talking this way in fact in the summer of 1967 I was flying warheads in on the Soviet Union as part of our mervich effort and I what I say is I couldn't see a better way to improve our national security then I can now before we get there we need to develop your scientific and intellectual capabilities you go to San Fran and by my lights burned your way through Stepford I mean you you're in one year you've got a master's in two more years in fashion actually one year that's fear okay technically it took me two years more to get my PhD because you had to have two years but I left after one year and did research at IVF that's a neat little story the in my second year of graduate study so the first year I'm really working on research at any level I'm still taking three courses which is for many people would be a full-time load and for me was a three quarter load so I'm only working one quarter time on my research but I start to wonder and this is actually a really helpful thing for young people working on their graduate work many of them have said how much it helped them I started to wonder who who the hell am I to think I can make an original contribution to knowledge which is what you do for PhD thesis maybe I should drop out of the program I works not going anywhere as my mother said I was going to hurry from the from the day I was born and I actually was you know contemplating should I drop out of the program and then spring break came so sister at this time of year 1967 and I thought you know I haven't really been able to work full time on research let me take a week you know Monday through Friday I'll take the weekend off and rest up but Monday I'm going to start at nine eight to five I'm going to work on research well within the first half-hour I had the key result that became the central part of my thesis there was more we had to do but in roughly half an hour I went

from thinking Who am I to make to think I can make an original contribution to knowledge to having them look the most important part of the result and I love this I tried for another hour to to take it to the end that I couldn't and my advisor my thesis advisor was at a conference I couldn't talk to him and this was before email 1967 the darkest yes but rather than foot then swipe driving myself as I hope they did later in life and sometimes do now I gave myself the rest of the week off because I felt that I'd done in that hour half hour hour and a half I'd done a week's worth of work and actually done it yeah a year several years worth or and so I took the rest of the week off and had a good time apropos of pleasure you know and when my advisor came back he agreed I mean he was excited too and it took us a month but it only took us a month because it was so simple to get from there to the end we've tried more complicated things than with a very simple approach that he actually came up with his calculus of variation standard mathematical technique that took us from my important thing to the end so I act so now Here I

am it's spring 1967 I'm in my second year of grad to work and I take in the summer off so I've only done three quarters and two or three quarters depending where you're talking about it and I'm basically done with my thesis and so when fedway was formally called wow this was learning the finite memory it was very different from cryptography although it had to do with statistics and probability was so it's related but we were married at that point for a little over a year and plans keep changing we work on our kids for five years but a year into the marriage we decide to have our first child and Dorothy is now pregnant and I like money especially didn't have much living on and no 200 a month I mean which admittedly was more than today fellowship so I go to Tom cover my advisor and I say you know I just have enough coursework to get to get the PhD I don't have enough research units but I've done the research could I go work at IBM research and you give me you know I won't be here but you'll give me credit for doing the research I do there and I can get paid money then he said fine and advisers and hospitals can say if I supposed to say no ghostwriter so no I was not because I was done with the field I was done with the thesis so is fighting it was just basically Stanford wanted more money and so that was the other neat thing I thought I'd pay that out of this huge salary that IBM was paying me compared to the 200 a month I've been living on IBM was very generous and they made me an IBM fellow that is the different kinds of IBM costs but this was a graduate fellowship patient greater than what it was and at

the Watson Research Center in New York and they paid my my tuition and they even paid our obstetric bill I mean it was unbelievable Eric's for never being greedy or we got to keep the system going now half the Watson the cold lab or Watson Research Center walking TJ Watson research I'd like to know because yours has been a very collegial what friendless initially but collegial certainly but a friendless may have been in my imagination I understand but certainly a collegial life um what is the collegial scientific life at the Watson Center and how were you locked in a separate room are you is there discourse going on what are people interested in finding out well there was a lot of interaction but the most important relative to my later career was with a man named horst feistel who had been hired roughly at the same time I had IBM was starting it script it's research effort in cryptography they could see the need on the horizon and I think they were thinking primarily in terms of time shared computers where multi people are using the same computer whereas prior to that you one person at a time would run on a computer and how do we keep your program from reading my data and they wanted to encrypt it and so they hired Feist Dell from mitre corporation in Massachusetts he was in the same department that I was and I didn't work I wasn't working on cryptography but I would have lunch with him I talked with him and so that was one of the key things that got me interested in cryptography a seeing that IBM was spending money on it which meant that I reinforced my belief for maybe created the belief that there was a growing commercial need for encryption and B if I Stella described to me some of the classical cryptographic systems like one of them you take your message written out in English I could tack it dawn you then take the text of a book like in the beginning God created the heavens and the earth and you add them together you think of a is zero so in the beginning God created heaven heavens has an A in it so ever the a is in Heaven's that gets added to whatever letter of attack Adonis underneath it and you just get that letter if it had been a B above it it would move it ahead one and so on and it seems impossible to break that cycle without knowing what the book is because then the person at the other end subtracts in the beginning God created the heavens in the and of course explain to me how it could be done and it was very easy and I studied information theory as for my PhD and it was really information theoretic because it has to do with the fact that English is more than 50% redundant like you can leave the you when you have a queue followed by you in English you could just leave the you off transmission and add it back in at the other end and it turns out there's a lot more redundancy than that and you can compress English by about 4 to 1 and so this is a 2 to 1 compression because you have your message attack it on when you have the book which is the second message being compressed into the length of just one of them but because it's 2 to 1 it's at least 2 to 1 redundant in theory it's potentially possible to break it and in fact it is do you begin to think of yourself as in cryptology at this point not yet not sure so there were three key events actually that January why was that IBM I went to my first international symposium on information theory and the banquet speaker was David Kahn the author of the code breakers which at that point was the best-selling book of the history of cryptography and that was one of the influences horsefly still at IBM was the second and the third key influence was the year after 1969 after one year at Watson IBM I go to MIT and I'm an assistant professor in the information theory group and Peter Elias now-deceased was one of the original contribute their contributors to information theory and he gives me a monograph it was a reprint of a paper that Claude Shannon who was the father of information theory had published in 1949 in the BST J the Bell System technical journal linking cryptography and information theory and oh I'm an information theorist and that's when I realized cryptography is a branch of information theory which had escaped me and most other information theorists information theory is concerned with coding information coding for compression as I just described coding for error correction so like you might repeat each one of three times attack ad or might become a a a TTT so if there's a single error made you can correct it like if a a a comes out a CA is there that's probably an A but there are much better ways of doing error correction and then

the third way that I had missed up to that point was coding for privacy and authentication which is cryptography and it actually turns out that Shannon had worked on cryptography during World War two at Bell Labs and that 1949 paper was a Declassified version of a 1945 classified report so his work on information theory which was published in 48 seems to give rise to the 1949 paper if you just look at the public dates so when you look at the footnote and realize that the cryptography work occurred in 1945 and you see how similar it is to the information theory work you realize that information theory probably owes its birth to cryptography Shannon's work in cryptography now are you at ideas at MIT that you me a hell researcher will become very important to development you're thinking about cryptology what deal did they did no no no I didn't meet him until the fall of 1974 also 1969 to 71 I'm an assistant professor at MIT MIT I come back here in 1971 as an assistant professor and then subsequently associate in full and now emeritus basically retired status why did you leave MIT wasn't that paradise oh god no let's forgive me MIT I really wanted to stay at Stanford but my advisor it's that it's really important to go away for a few years Stanford was concerned about inbreeding it still is but we sometimes hire our own PhDs because if you hire a Stanford PhD at Stanford he or she is largely replicating the thinking of there advisor and you want to get new ideas and so I had seemed at the time like I had to jump through the stupid hoop of three years in exile as I joke about it on the East Coast IBM and MIT but I was going to come back and work with my advisor I really want to detain you for a second if it's possible to describe the intellectual confident MIT even if you intention to go back to Stanford anyway however after does become the gestation point of such phenomenal thing but what what is happening at MIT is a collegial on the question being asked there interesting to you yeah well first of all Peter Elias giving me I mean obviously there was interaction and collegiality I mean Peter it wasn't like I asked about it but I mean it's just a mild maybe I mentioned by Stella or something and finish that oh but every minds me here's this paper in here he gave it to me and Bob Gallagher was very helpful to be Dave Forney who had left MIT and was an industry that very closely associated there was a lot of interaction who was the dream of California the dream oh yeah I read I grew up in the Bronx and so let's see what drew me to California logically I can point to things like I wanted to I have several answers I ran away from home my mother my brothers and I had joked my mother was an amazing woman we have joked if she in fact dark and I said if she had been born a generation later she would have been running a billion-dollar company instead being born in 1914 she put all that energy into raising me and my two brothers which made us want to run away from home right and that's one answer another I was running away from the ethnic consciousness of the Bronx and California was much better that way the Beach Boys were singing about California Gurls Mamas and Papas California Dreaming this is the 60s yeah I understand so I was pulled but I think at a more mystical level and I am a scientist and engineer but I have a strong belief in forces beyond our understanding and have more than a belief or conviction I've experienced them in my own life I had to meet Dorothy I didn't know I had to know Dorothy but she's has been amazing and she saved my life she saved your life oh yeah it's Award for her I'd still be doing cybersecurity or pretending to do it because I'm 71 I mean mathematicians are dead by the time they're in their mid-thirties there's some exceptions but but also people in academia want to work on the really big problems like public key cryptography well a bigger problem is there what bigger issue is there than the survival of civilization and I wouldn't be working on that if it hadn't been for her oh and it's more than that I mean it it helped me to shed the more than help sheet I wouldn't there couldn't stay married to Dorothy in fact we're headed for divorce 40 years ago we've got to talk about that I guess what it situates you at this time so uh why don't come back I love California I mean there was all the things I said fun it was not the Stanford intellectual culture I would be reaching oh I'm suggesting that Rory there okay my junior year my first technical job working on microwave plumbing my old girlfriend the first serious girlfriend and I talked about she'd moved to San Francisco and she mentioned this University down the pence I'd ever heard of Stanford in 1964 I mean it was it was it it was not known the way it is today and I figured because it's in California it's got to be laid-back and easygoing this was the picture I had in my mind I mean every part of California was on the coast even Bakersfield right that's it isn't it and I remember that summer job I was carpooling with another man and he he wanted to go to Princeton for electrical engineering graduate studies and I want to go to Stanford and I was we were kind of commiserating how he was going to be working hard at this Ivy League you know type a school whereas I was going to be basking in the California Sun honor yeah when I felt yeah of course the service I mean he would actually I did wind surf here with a wetsuit but there the bay is cold but when I found that Stanford was a top school I came anyway so that's not a funny story so here you are you're back in Stanford what are your intentions at this point intellectually was converted in a way pathology not yet not yet no so the kind of rule of time so there was the Ellenville conference in 16 I'm sorry the information theory symposium which was in Elland only or at 1969 it was five still at IBM in 69 I'm sorry 68 to 69 house at IBM and then Peter Elias MIT 69 to 70 when I start playing with it and it grew with time and every time I go to a conference and people would say what are you working on I talk about data compression and other areas of information theory and then I'd say I'm also looking at cryptography and my colleagues response I believe was absolutely uniform which is you're crazy to work on cryptography and the answers tended to be the same NSA the National Security Agency has a huge budget we didn't know how big until Snowden's revelations they've been working on it for decades you know how can you ever hope to discover something they don't already know and if you do anything good they'll classify it these were the two arguments that were made what were you not smart enough to listen to them oh why was i smart enough not to listen really is it well this is the wisdom of foolishness lecture that I love I think getting beat up as a Christ goer had something to do with it I mean I wouldn't want to go back and live through that again I wouldn't wish it on anybody else but growing up I wanted to be like the other kids but I couldn't be like yeah the kids for many reasons but let's just focus on the jewelry versus not serious part in self-defense I adopted the attitude of who would want to be like everybody else well me of course I mean it was it was a protective coating and but in time I I came to believe my own and I when people my colleagues said you're crazy to do that rather than chasing me away if anything it drew me right right so were crazy it turned out to do it no in fact in the wisdom of foolishness talk I I talked to I could probably have a dozen or more colleagues who were told they were crazy to work on breakthrough technologies that they worked on and in my Stanford engineering hero talk which is on YouTube people can find it just

Google Hellman Stanford engineering hero it's the wisdom of force miss Vince Cerf who was key in development of the internet says people thought packet and I email each of these people four or five of them to make sure I got to write he said even after the success of the ARPANET which preceded the internet people thought packet switching would not work and for things like audio and video and of course today all your Netflix and Amazon Prime videos come over packet switching Federico fission who designed the first microprocessor at Intel had a similar story and so the with a not diversity but foolishness seeming Felicity and actually it's what you when you were talking about seeking you know doing what you want to do it would a fool would do what they want to do instead of what they think they ought to do and yet so this comes back to that mystical side of life will report I sometimes joke that there's a muse of cryptography or a muse of civilization surviving who whispers in our ears and she picks oh no she talks to everybody she talks this girl she talk to her but only a few fools listened to her that's why she has to talk to so many people remember so how do we get you full time into cryptology hmm fighting schools challenging some of the current notion and then fighting NSA and then probably had to say how you how does that happen about the mid-seventies rightly done so well it started in 68 at IBM and 69 and I'm starting to spend more time on it and I get a small result I mean but publishable and I realized oh I maybe I can do this I start spending more time but I'm stealing because I have NSF grants and I've got a fos our Air Force Office of Scientific Research financial support and I didn't want to do anything in cryptography under those because then an NSA would descend on me right to my surprise my NSF grant monitor when I told that you know spending my own time on that he says no do some of that under the NSF grant and as I start to get good results to my great surprise even even greater surprise my contract monitor at AFO SR says the same thing so I'm starting to split now I can spend some of this grant money I can I don't have to steal time and then wikked if he shows up which is critical okay have him descend yet or what actually came by he came by Datsun five something or whatever they whatever the Datsun was that he was driving there so this is not somebody who anybody in the world would say was equivalent of your personality this is not now behind person now headlong and still has long blonde hair now it's wider very counterculture I mean he he takes wisdom of foolishness a little further than I do and so what happened was in the fall of 1974 as I'm starting to spend more time on cryptography but I'm also beginning to feel a little isolated I mean I like being the fool and doing what no one else does but it's also a little scary and a little lonely I get a phone call from this guy named with Diffie and he says alençon hime who heads the cryptography research group at IBM it suggests that he looked me up when he's out in the Bay Area he'd been traveling around the country and so we set up i forget was a half hour or one hour meeting at my office about five minutes from here and i mean III didn't know that this was going to be I I mean I said it half an hour an hour figuring okay it would be mildly interesting after half an hour an hour we're going wiegel on and on and on I mean we just have such a meeting of the minds and he's been working alone I'd been working alone and we had some of the same ideas he had ideas that I hadn't had that I liked and vice-versa so after I there must've been several hours of meeting with him in my office I look at my watch and I say I promised my wife I'd be home to watch our girl so this is 1974 the three and five I'd love to continue this but we have to go back to my house on campus it's very close to here can we do that he says sure he just has to let Mary Fisher his wife know about this they join us for dinner at our invitation and we've at 11 o'clock at night and we were and wasn't like oh my god they're they finally got out of here was just fantastic the meaning of four really haunted yeah the two of you right oh oh yeah Mary was interested in dogs dorothy was very interested in dogs a lot of things to come so what was the and I know it's difficult to compress a certainty but the key insight that you both felt an affinity about that was going to leave just in a couple of years your major feature yeah to listen to a year and a half you actually listen a year and a half still the algorithm I came up with the algorithm now known as diffie-hellman key exchange although I've argued it should be called diffie-hellman merkel will talk about feelings and I was in this study right down here that I can't show you because I've moved a lot of junk in there but late one night but what actually was talking about public key cryptography for maybe six months or nine months I mean we were talking together before that and we've had some ideas together like something called a trapdoor cipher that had even preceded that what was the problem that you needed for thought you could core weather actually I'm going to trace it back to trapdoor cryptography one of the cryptography is an interesting system were a problem when you and I are talking we want secure encryption so that he can't listen unless the guy sitting over there then when I talk to him I might not we may not want you to listen it right and put in a middle to put that in a military context you guys are on one time I'm going to change it you guys are on one side in a conflict and I and my guys over here are the army on the other side we want secure encryption that you can't read but you might capture our encryption device and start using it against us right so we want we realize fairly quickly is the ideal cryptographic system from a military point of view would be a trapdoor cryptographic system one that would have secret information built into it you might know it's built in but unless you know exactly what that bid sequence is you can't break it but if you ever capture it and because I built that bit sequence in I know how to break it and from there to public key cryptography is not that big a step because if you can do trapdoor encryption and generate them at will let's say you and I want to talk securely separate from the guy behind the camera over there I create a trapdoor crypto system I say it to both of you because I mean I'd like to tell it only to you but the cameraman hears it to you then take that trapdoor system encrypt a message to me Marty here's the key we're going to use right you encrypt it he can't break it you couldn't break it if you didn't I mean it's easy but I can break it because I've got the trapdoor information right that's public key cryptography right and so that answer your question is but I think also in your process there are people thinking about that problem of coming up with upside factor in Meriden the NSA from the unsatisfactory patches to that but they weren't unsatisfactory part of the thing was when you go from no encryption being primarily of military significance to being of commercial use it changes it in the May your way in the military you have a chain of command a private in one company does not talk to a private in another company he talks for sergeant who talks to lieutenant who talks to the captain who talks to the other lieutenant sergeant and private so the number of connections is limited whereas commercially or now anybody might want to talk to anybody so the number of keys that you need the number of connections you want to make goes up literal loud knock may expand it goes up here by a huge amount and so key exchange which was a major problem in the military becomes an almost impossible problem in the commercial world and that's why public key cryptography was so important now as you said it was not just two of you in his conversation this transformative confirmation the three of you actually and you talk about the third yes the third guys Ralph Merkle so wit and I are working here at Stanford I was able to get him to put some roots down and stay here I was worried anxious to have him stay and he had machen done before hold pH near Austin well that's another story we'll come to that moment so we're working and we've come up with the

public key idea but we have not yet come up with the algorithm that I talked about and but after coming up with the basic idea but before the algorithm went through a friend at Berkeley hears about this student Ralph Merkle who's an undergraduate now master student working on cryptography saying somewhat similar things and Ralph again is a world-class fool in the best sense of the word he proposed developing public key cryptography for a term project in CS 244 Berkeley Graduate course and the professor had discouraged him from it now admittedly when he wrote on the paper and Ralph saved it and I scanned it it said maybe because your explanation of idea number one which was public key cryptography was so muddled hello he doesn't believe us yeah that's what the professor said to him that maybe was muddled and so Ralph independently of us was working on related ideas there's differences and he didn't have digital signatures but he came up with his ideas actually before us and that can be documented but we didn't know about that and then we each heard of the other after we had been working and had grown together but the other thing when Ralph submitted his paper to a journal unlike mine I had been invited to write a paper and when I came up with the diffie-hellman of diffie-hellman merkel key exchange algorithm in May of 1976 I presented it at a nother information theory symposium in June the following month I had a paper accepted with the general idea now I had a specific way to do it a good way to do it and the editor of the journal was at that who invited me to write this paper and I asked him would could join me in the paper which he said fine to the editor was there and he said you get that result in and I'll have it in the November issue of the transaction and he did it yes and simile RSA Rivest Shamir album that at MIT when they came up with their algorithm which had seen great commercial use the I was one of the reviewers I get a letter from the editor please review this paper as fast as possible it may be the most important paper we ever published now editors don't usually say not like that poor Ralph his editor didn't say that Ralph's editor sent it out to review to an expert in cryptography presumably at NSA who said this is not in the mainstream of cryptographic research and questioned whether you could do what he was saying even though he showed he had a proof of concept in it the guy just didn't understand the paper the editor writes back and graph again has these letters it bothers me that you have no references we had no no bibliography in his paper has no one ever thought of doing anything remotely resembling this before and the answer is no they hadn't I was seminal research now in the editors defense Ralph should have had some references you know and he didn't know how to write a paper he was a either an undergraduate or masters student when he wrote that and with no benefit I mean a professor would discouraged him and so that that's Ralph Merkle and he deserves in my opinion equal credit for the invention of the key exchange part of public key cryptography there's two parts the key exchange which is what I described and then there's digital signatures and Ralph did not have that admittedly which is one reason I think the ACM award was given to just two Witten me although it's kind of a toss-up how it goes there's no signatures talked about out of it okay most people when they think of cryptography think of privacy not authentication but really in cryptography and concerned with both privacy and authentication and let me explain that in why authentication which people don't think of is probably the more important of the two think of writing checks on your bank account if privacy is violated that camera guy over there can read every check you write on your account but you're unhappy if he that happens if what vindication is violated he can write any checking once on your account which makes you more unhappy the second one thing and so what you need for now cryptography always had some form of authentication but with public key cryptography you get an even better form normal cryptography prior to public key would allow the two of us to communicate and prevent the cameraman from either reading what we have written or altering what we've written so there's no privacy and authentication but you could alter what I've written to you and make it look like it came from me I could alter what you've written to me because we share a common secret key in conventional cryptography in public key cryptography there's a public key and a private key and when you do digital signatures the secret key the private key is used to sign the message and the public key is used to verify it right and so you can sign cheques digitally much better than we can sign cheques paper checks a paper check somewhere might able to change for not change the number because the same signature is used for a hundred dollar check or a hundred million dollar check line whereas a digital signature depends on the contents of the message and so the my signature on a hundred dollar check is totally different from my signature on a hundred million dollar check although it uses the same private or secret key to create it okay now we're going to send your insights out into the world and I'm just going to put it in a category of security and let this new key exchange allows and commercial impact as well so security which is both national as well as commercial and then the commercial side what happens when your paper is presented to the world a lot of excitement in the academic world the commercial world a lot of consternation in the at NSA the classified world and probably their foreign equivalents and that's because they regarded cryptography as their monopoly and they were concerned that if we tell Americans how to protect their secrets from criminals and foreign countries we're also telling foreign countries how to protect their secrets from NSA but telling terrorists and criminals how to protect their secrets --is you can't get around that right and that this course goes off more than this course a war or initially so my colleagues remember the two arguments NSA has a huge budget how can you hope to discover something they don't know and if you do anything good they'll classify it they actually understand if you do anything good they might kill you or their foreign equivalents might kill you right now that's the implication with that yes and so Dorothy was very happy when this quiet war became a more public war and was covered in the New York Times they had an editorial supporting our positions science magazine had a number of articles she said now if something happens to you there will be an investigation and I'm not necessarily saying NSA would have done it but and I don't even know that I was at risk but when you're angry not only an estate but their soviet equivalent remember and the stakes were very high yeah the stakes are very high and as you say it continues payments controversy with Apple and yes a and terrorism hello attention in the Apple currently the FBI is saying what NSA used to say forty years ago which is you know we need our needs to take precedence over your personal your private needs and commercial needs and a say on the law to the law a large extent has been on our side several former directors of NSA have said FB the FBI was wrong and one of them even said Jim Comey is wrong well adapt it we'll get the names and even the current director of NSA oh yeah I can well actually this is a video I can't keep there can't send you links after a bit they're in my computer

library anybody can find a Bible reader oh and why is that yes well about two two and a half years ago admiral inman who was the director of NSA when i was publishing when we were publishing these papers and who loosely speaking wanted to throw me in jail for publishing them he later became a friend i mean initially an adversary and then friend cautiously at first but in an interview he was asked with what he now knows would he still try to suppress our work he said quite the opposite i would try to get it out as quickly as possible because he now sees that from the broad perspective of national security commercial encryption strong commercial encryption is very important and he cited theft by presumably the chinese of jet fighter plans from american businesses as an example among the many implications and aspect of your work some some attributed to that the world wide web would as we know it wouldn't really be working without this is that oh no we're safe learners well it would work for anything unconfident but all the electronic banking you do when you purchase things with a credit card and about three years four years so if someone told me that true of dollars the day and financial transactions were protected using our technology and I said no you mean trillions of dollars a year and he said no I mean trillions of dollars a day and I checked in he's right foreign exchange transactions which are all protected by this are about five trillion dollars a day unfortunate our patents ran out no there's a hell for a while now we made almost no money for a patent you made almost all ya RS they sold their patents for 200 their their company for 250 million dollars there's a patent fight between RSA the MIT guys and Sanford bottom line is they outspent us and we lost although maybe it's different I'm friends with them now is where existed them for a long time but there were good earlier so I want to that'll talk about they'll actually they might think they could I went back and thought through that fight from their point of view because just like the way our marriage went from being headed for divorce forty years ago to not having had a single fight in probably 15 years and being in love the way we were when I first met I rethought the patent fight those one way we did that is when Dorothy does something that annoys me instead of just being annoyed I would try to think it through from her perspective I do try to think of them from her perspective and it's often very different from what I thought in the same way I went back and rethought the patent fight that we had with RSA and I can see how from I don't know for sure but from their perspective they might think I started the whole thing right I want to talk about it here to finish the interview about the ethicist because you're one of the scientists technology scientists who thinks about broadly the the implications of science technology security privacy and so forth at what point in your career did you begin to become as outspoken on the ethics of science and really a relationship in the world as they affect are affected by it how did you forget to 1981 there's much yeah well so what happened was what the short answer is what caused me to make this shift is my wife wanting to preserve my marriage coming to see that my marriage was in trouble I was so busy working that I changed from the way I was when I took the week off after getting that great well I could become a slave driver to myself and but Dorothy was in touch with that and she was looking for catalysts and she tried several different things and because she didn't know what to do either and she was making mistakes just like I was but then in 1980 she found that or a group that no longer exists so we're not recruiting people for the group and I was very arms-length at first but by this summer of 1981 when she dragged me to enough meetings and we done enough work like that's when I first realized how my mother must have felt when my father went off I mean he'd been in the Army for a couple years when he went off overseas to the South Pacific I'd never thought about that before we did a lot of deep personal work and then in the summer of 1981 we took a week which I never would have taken a year earlier to go to a seminar looking at how a number of the bigger issues of the world the bigger issues of our lives and during that week I saw that these people knew something I had to learn if my marriage was going to survive and I dropped my resistance through it through my lot in with them but they also were working on global issues and that fact was that that week-long seminar that I saw day after Trinity a documentary about the making of the first atom bomb because the first test in the New Mexico desert was called Trinity site and in that documentary they interview about five or six of the scientists engineers who worked on the Manhattan Project and they asked each one of them what was your motivation and each of them says Nazi Germany I mean fission had been discovered in Germany in the late thirty if Hitler got the bomb first it would be a thousand years of dark ages we had to and you could just see they're reliving the excitement they felt working on this important project to save the world from disaster but in that same documentary they come back to each one of them and say so when Hitler was defeated when our only enemy was Japan and your stated mode they don't say if it's implicitly your stated motivation was gone why did you keep working on this horrible weapon and their faces drop one of them even develops coming nervous twitch Robert Wilson he actually vomited I found of that later this isn't in the document when he heard that the bomb had dropped on Hiroshima he had to stop he was going from one lab to another at Los Alamos and he just stopped and threw up and watching the film I could not be sure but I believe they did what I had done in 1976 when I had to decide whether to go public with my fight with NSA I was trying to throw out the right thing to do and the idea popped into my head forget about what's right or wrong you've got a tiger by the tail run with it you'll never have as much chance to be well-known the famous infamous whatever at the time I thought I'd brushed that I call it the devil on my shoulder like in the movies I thought I'd brushed him off my shoulder but watching day after trinity' five years later because that was 1981 now I saw that I had fooled myself I figured out what I wanted to do and then gone and done it I then come up with the rationalization for why what I wanted to do was the right thing and I believe the Manhattan Project scientists had done the same thing and I vowed never to do that again although actually when I refer people to a book my wife and I finished and it's not a book sales job because people can download a free pdf buy it's a new map calm a new map three words run together and there's a get the book has that place we can download a free PDF and search on devil on my shoulder or a day after Trinity would get it and the stories in there about why even after I made that Valve that I was never going to fool myself again some years later when I was put in the patent fight with RSA I couldn't be sure I wasn't fooling myself I wanted to do something if we made good in the sense but by the way it also had the chance to really get them fact someone came to me and said you help me do this we'll get those RSA bastards by the balls he gives way he spoke his exact words and I didn't want it I mean the vengeful part of me which was still active at the time I couldn't be sure that wasn't fooling myself and Dorothy came up with a wonderful solution which is described in the book to make sure I wasn't fooling myself

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