Starts at 2:00

1

Starts at 2:00

Advertisements

*[I was delighted to receive the following guest post by Chris Brzuska about a meeting that took place last week during Eurocrypt in Tel Aviv. This piece will also appear in Omer Reingold’s blog. Let me take this opportunity for a couple of shoutouts. Next week it’s going to be two years since Italy, last among Western European countries, has instituted same-sex civil unions (yay!) and the parties that opposed it now have an absolute majority after the last elections (boo!). The Berkeley EECS department has an LGBT+ graduate student organization called QiCSE that organizes a very visible breakfast meeting during the visit days for prospective grad students and regular meetings during the school year – as much as I value Berkeley exceptionalism, think about creating something like this in your own school. It would be great if there was a LGBT+ meeting at STOC this year; I am not going to STOC this year, but maybe someone else can take the lead. And now, on to Chris’s beautiful essay. Congratulations, Chris!. — Luca]*

I gender-transitioned two years ago, and Eurocrypt 2018 in Tel-Aviv is the first major conference I attend since then. I am a bit nervous. How much time does it take for 400 people to update my name and pronouns to use “Chris” and he/him? Two years feels like an eternity to me, but surely, some people will not have heard about my gender-transition. I will need to come out to some people.

Coming-out is very empowering, but after two years and uncountable coming-outs, I really wish that everyone knows that I am trans and gay.

A gay friend of mine remarks that when being bisexual/lesbian/gay, coming out is really never over, and one needs to come out again and again, to each new person. And really, he says, there is rarely a good time to bring it up.

“How come you didn’t know I am lesbian/gay?”, I heard from several friends, in shock, worried I might have wrongly assumed they are heterosexual.

How many LGBTQIA people are in our communities? I know some LGBTQIA people in the community, but how many more are there, and how can I find them?

This simple question leads to something which would become more important to me than I expected initially.

In the rump session, I give a coming-out talk, combined with an announcement for an LGBTQIA cryptographers meeting during the rump session break ( https://eurocrypt.2018.rump.cr.yp.to/4f756d069387ee90de62454a828a3b9b.pdf).

Giving this talk in itself was very nice. I enjoyed sharing my happiness with the community, see my happiness reflected in other people’s eyes. I enjoyed the many positive comments I received during the hours and days that followed, and the recognition of daring to be visible.

During the break, I am excited and nervous. How many people will come to the meeting? And who? More than 10 people come, most of which I knew without knowing they are LGBTQIA. We walk into the room, one by one, each with light in our eyes. We came out to each other, all of us, in that moment. It’s intimate, moving, exciting. Coming out remains deeply personal. It can be daunting, even in a warm, progressive environment such as our research community and even to an LGBTQIA subgroup.

After the rump session, we go to the gay-lesbian bar Shpagat in Tel-Aviv, in happy excitement. We are the last customers that night. The next day, during the breaks, we often find ourselves with a majority of LGBTQIA people in a conversation, we sit next to each other during talks. Something important happened.

In light of our increased visibility (to each other and to the community at large), there were more opportunities for coming outs the next days (or so was my impression, although I am only conscious of 2 explicit cases…). It was very liberating for me to share many of the following conference moments with LGBTQIA cryptographers who would add additional views to a heterosexual, cissexual perspective, and who would help me explain the sensitive issue of coming out to other caring members of our research community.

The research community is my permanent country of residence, my frame of reference, the source of almost all my long-term friendships – and enfin, in this country, there live quite a few LGBTQIA people, and the research community encourages us and shares our happiness.

We are going to organize more LGBTQIA meetings alongside cryptography-related conferences. I hope, there will be more such meetings inside and outside of CS. And we look forward to see the number of LGBTQIA researchers (that we are aware of) grow.

If you are an LGBTQIA researcher who wants to get in touch with us more discretely than at a public meeting (to talk to one of us, e.g., in the beginning of your PhD etc.), you can send an eMail to queercrypt@gmail.com. You can also use that eMail address to join our mailing list (for event announcements) and/or our WhatsApp group (include your phone number if you want to join the WhatsApp group). While the group centers around cryptography-related events, the group is not limited to researchers in cryptography.

Over the past four decades, Avi Wigderson, figuratively, wrote the book on theoretical computer science. Now he has literally done so. I can’t wait for the movie adaptation.

(Photo credit: ACM)

Formally ending a search started in March 2016 (and a process started in the Fall of 2015), we are pleased to finally officially announce that Shafi Goldwasser will take over from Dick Karp as director of the Simons Institute for Computing on January 1st, and will return to Berkeley after a 30+ year hiatus.

Shafi is the co-inventor and developer of the notions semantic security in encryption; of zero-knowledge proofs; of pseudorandom functions; of the connection between PCP and hardness of approximation; and of property testing in sublinear algorithms, among others. She has received the Turing award for her work on cryptography and of two Gödel prizes for her work on complexity.

I cannot put in words how happy I am for the Berkeley community, including myself, and for the future of the Institute.

The director search was my first glimpse into how the Berkeley central campus bureaucracy operates, and it was horrifying. The simplest thing couldn’t be done without a sequence of authorities signing off on it, and each authority had a process for that, which involved asking for other things that other authorities had to sign off on, and so on in what at times seemed actual infinite descent.

The announcement linked above was in the works for *at least three weeks*!

Alistair Sinclair, after two terms as associate director of the Simons Institute, during which his heroic efforts were recognized with the SIGACT service award, also retired from his position at the Institute, and last July 1st was replaced by Berkeley professor Peter Bartlett, a noted pioneer of the study of neural networks.

This weekend, on Saturday, the Simons Institute will host the FOCS reception, which will double as celebration for Alistair’s prize. There will buses leaving the conference hotel at 6:45pm, and there will be plenty of food (and drinks!) at the Institute. There will also be buses taking people back to the hotel, although once you are in downtown Berkeley on a Saturday evening (bring a sweater) you may want to hang out a bit more and then take a rideshare service back to the hotel.

I was really delighted with all the prizes that were announced at STOC this year.

Our own Pasin Manurangsi received the Danny Lewin STOC Student Paper Award for his work on the hardness of the dense k-subgraph problem. This is the problem in which we are given a graph and a number k, and we want to find the set of k vertices that induces the most edges. Pasin, who is co-advised by Prasad Raghavendra and me, discovered a new, simple but ingenious reduction that establishes hardness up to almost polynomial factors.

I received the same award exactly twenty years ago, also for a hardness-of-approximation result established via a simple reduction. (Prasad also received it, nine years ago, for a hardness-of-approximation result established via a difficult reduction.) I then spent time at MIT, where Oded Goldreich was, and, partly thanks to his influence, I did my best work there. Pasin is spending this summer at Weizmann, where Oded Goldreich is, so, no pressure, but let’s see what happens. . .

Alistair Sinclair received the ACM SIGACT Distinguished Service prize, for his work setting up and leading the Simons Institute for the Theory of Computing.

Those who have been to the institute, that is, almost the whole theoretical computer science community, have seen that it is a place uniquely conducive to do good work. If you stop at think about what it is that makes it so, Alistair’s hand is behind it. The open layout of the second floor, with the whiteboards dividing the space and absorbing sound? Alistair worked closely with the architect, for a year, during the renovation, to make sure that the design would best fit the needs of our community. The friendly, competent and responsive staff? Alistair sat in all the interviews when the staff was recruited, and participates in their performance review. So many things happening and never a conflict? You know whom to thank.

More substantially, almost all the programs that we have had were, to some extent, solicited, and Alistair led the conversations and negotiations with all prospective organizers, shepherding promising concepts to approved programs.

Alistair has also been relentless in making people do things, and making them do things by prescribed deadlines, something that is notoriously difficult in our community. The Simons Institute programs have succeeded, in part, because of the tremendous amount of volunteer work that the organizers donated to our community, and while they would all have been extremely generous with their time in any case, Alistair made sure that they were extra generous. A personal anecdote: I was one of the organizers of one of the Fall 2013 inaugural programs. At that point, I was at Stanford and we were beginning to discuss the idea that I could come back to Berkeley. At some point, around October, I get a phone call from Alistair, and I assume he wants to talk about it. Instead, he goes “you know, I haven’t been seeing you much at the Institute so far. We expect organizers to be around a lot more.” A few months later, I got the offer to move to Berkeley, with a 50% affiliation at the Institute. Even knowing who my boss would be, I enthusiastically accepted.

Oded Goldreich received the Knuth Prize. I have already said how I feel about Oded, so there is no need to repeat myself, but I will add that I am also really happy for the Knuth Prize itself, that has managed to consistently make really good choices for the past 21 years, which is an outstanding record.

Finally, and I can’t believe that it took so long, the paper of Dwork, McSherry, Nissim and Smith, that introduced differential privacy, has been recognized with the Godel prize. I am very happy for them, especially for my matron of honor and former neighbor Cynthia.

Congratulations to all, and by all I don’t mean just the aforementioned awardees, but also our whole community, that nurtures so many great people, inspires so many good ideas, and makes being part of it such a joy (even when Alistair makes me do things).

At the aforementioned Oded Fest that took place at Weizmann a couple of weeks ago, Silvio Micali read from an epic prepared speech, which tied together the early work on foundations of cryptography, ancient Greece, the Renaissance, Viennese cafés, and the movies “Chariots of Fire” and “The Seven Samurai.”

Silvio has given his kind permission to share the speech, and he has put it in a pdf form that includes the pictures that he used as slides.

I have been in Israel for the last couple of days attending an event in honor of Oded Goldreich‘s 60th birthday.

Oded has touched countless lives, with his boundless dedication to mentoring, executed with a unique mix of tough love and good humor. He embodies a purity of vision in the pursuit of the “right” definitions, the “right” conceptual point of view and the “right” proofs in the areas of theoretical computer science that he has transformed with his work and his influence.

A turning point in my own work in theoretical computer science came when I found this paper online in the Spring of 1995. I was a second-year graduate student in Rome, and I was interested in working on PCP-based hardness of approximation, but this seemed like an impossible goal for me. Following the publication of ALMSS, there had been an avalanche of work between 1992 and 1995, mostly in the form of extended abstracts that were impossible to understand without an awareness of a context that was, at that point, purely an oral tradition. The aforementioned paper, instead, was a 100+ page monster, that explained *everything*. Studying that paper gave me an entrance into the area.

Three years later, while i was a postdoc at MIT and Oded was there on sabbatical, he played a key role in the series of events that led me to prove that one can get extractors from pseudorandom generators, and it was him who explained to me that this was, in fact, what I had proved. (Initially, I thought my argument was just proving a much less consequential result.) For the most part, it was this result that got me a good job and that is paying my mortgage.

Like me, there are countless people who started to work in a certain area of theoretical computer science because of a course that Oded taught or a set of lecture notes that he wrote, and countless people whose work was made possible by Oded nudging, or usually shoving, them along the right path.

The last two days have felt a bit like going to a wedding, and not just because I saw friends that I do not get to see too often and because there was a lot to eat and to drink. A wedding is a celebration of the couple getting married, but it is also a public event in which friends and family, by affirming their bonds to the newlyweds, also affirm their bonds to each other.

I was deeply moved by the speeches given by Silvio and Shafi, and really everybody did a great job at telling Oded stories and bringing to life various aspects of his work and personality. But perhaps the most fittingly weird tribute was Benny Chor presenting the Chor-Goldreich paper (the one that introduced min-entropy as a measure of randomness for weak random sources, and the problem of 2-source extraction) using the original 1985 slides.

Speaking of public celebrations, there is less than a month left to register for STOC 2017, the “Theory Fest” that will take place in Montreal in June.

*“Art imitates life, but life imitates bad TV” *(Woody Allen)

The mention for a major alumni award given by U.C. Berkeley is for *excellence in achievement*.

Meanwhile, in the episode “Brother, can you spare two dimes?”, Mr. Burns has to come up on the spot with the name for a fake awards, and he comes up with an award for *outstanding achievement in the field of excellence.*

(You’ll note that the dancers in the video are wearing gold and blue)

This Thursday (December 15) is the deadline to apply for post-doctoral positions at the Simons Institute for the next academic year. In Fall 2017 we will run a single program, instead of two programs in parallel, on optimization. The program will be double the size of our typical programs, and will focus on the interplay between discrete and continuous methods in optimization. In Spring 2018 there will be a program on real-time decision-making and one on theoretical neuroscience.

In a few weeks, our Spring 2017 programs will start. The program on pseudorandomness will have a mix of complexity theorists and number theorists, and it will happen at the same time as a program on analytic number theory at MSRI. It will start with a series of lectures. It will start with a series of lectures in the third week of January. The program on foundations of machine learning has been much anticipated, and it will also start with a series of lectures, in the fourth week of January, which will bring to Berkeley at impressive collection of machine learning practitioners whose research is both applied and rigorous. All lectures will be streamed live, and I encourage you to set up viewing parties.

During the current semester, the Simons Institute had for the first time a *journalist in residence*. The inaugural resident journalist has been Erica Klarreich, that many of you probably know for her outstanding writing on mathematics and computer science for quanta magazine.

Next semester, our resident journalist will be Pulitzer-prize winner John Markoff, who just retired from the New York Times.

1982 was the *annus mirabilis* of the foundations of cryptography. In their paper “probabilistic encryption,” Goldwasser and Micali introduced two rigorous definitions of security for encryption, which they proved to be equivalent. One definition required the distributions of encryptions of any two messages to be computationally indistinguishable (a concept they introduce in the paper), the other, which they call semantic security, is the property that whatever can be efficiently computed about a message given the cyphertext can also be efficiently computed without the cyphertext. Later the same year, Blum and Micali gave a rigorous definitions of security for pseudorandom generators, and Yao wrapped all these results in a more general framework requiring generic, rather than number-theoretic, assumptions.

The concept of semantic security inspired most subsequent definitions, and proofs, of security based on the concept of simulation. Instead of trying to specify a list of things than adversary should not be able to do, one defines an idealized model in which the adversary has no access to private and encrypted data, and one *defines* a given system to be secure if whatever an attacker can efficiently compute given the ability of eavesdrop (and possibly mount an active attack), can also be efficiently computed in the ideal model. One then *proves* a system to be secure by developing a *simulator* in the ideal model for every real-world adversary.

Together with Rackoff, Goldwasser and Micali took this idea one step further from encryption to interactive communication, and came up with the idea of *Zero-Knowledge Proofs*. A zero-knowledge proof is a probabilistic proof system in which a prover can convince a verifier, with high confidence, of the truth of a statement, with the additional property that there is a *simulator* that is able to sample from the distribution of verifier’s views of the interaction. Thus the verifier is convinced of the truth of the statement being proved, but gains no additional information. In their paper, Goldwasser, Micali and Rackoff introduce the concept and present a zero-knowledge proof for a conjecturally intractable number-theoretic problem. The paper was famously rejected several times, eventually appearing in 1985.

The following year, Goldreich, Micali and Avi Wigderson published a paper giving zero knowledge proof systems for all problems in NP. Their work made zero-knowdge proofs a key tool in the design of secure cryptosystem: it was now possible for a party to publish a commitment to a secret and then, at any time, be able to prove that has a certain property without releasing any additional information about . This ability was a key ingredient in the development of secure multi-party computation in 1987, by the same authors.

So how does one prove in zero knowledge that, say, a graph is 3-colorable? (Once you have zero-knowledge proofs for one NP-complete problems, you immediately have them for all problems in NP.)

Suppose the prover and the verifier know a graph and the prover knows a 3-coloring. A physical analog of the protocol (which can be implemented using the notion of *commitment schemes*) is the following: the prover randomizes the color labels, then takes lockboxes, each labeled by a vertex, and puts a piece of paper with the color of vertex in the lockbox labeled by , for every . The prover locks all the lockboxes, and sends them to the verifier. The verifier picks a random edge and asks for the keys of the lockboxes for and for . If they contain different colors, the verifier accepts, otherwise it rejects.

The protocol is *complete*, in the sense that if the graph is 3-colorable and the parties follow the protocol, then the verifier accepts with probability 1.

The protocol is *sound*, in the sense that if the graph is not 3-colorable, then, no matter what the prover does, there will have to some edge such that the lockboxes of and are the same, and the verifier has probability at least of picking such an edge and rejecting. Thus the verifier accepts with probability at most , which can be made negligibly small by repeating the protocol several times.

As per the zero-knowledge property, the view of the verifier is the choice of a random edge, two open lockboxes corresponding to the endpoints of the edge, containing two random different colors, and unopened lockboxes. A view with such a distribution can be easily sampled, and the same is true when the physical implementation is replaced by a commitment scheme. (Technically, this is argument only establishes *honest-verifier zero knowledge*, and a bit more work is needed to capture a more general property.)