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Posted by tkhattra 3 days ago

Michael Rabin has died(en.wikipedia.org)
387 points | 80 comments
xorvoid 12 hours ago|
Thank you Michael Rabin for your excellent work. Rest in Peace.

Rabin Fingerprinting is one of my favorites of his contributions. It's a "rolling hash" that allows you to quickly compute a 32-bit (or larger) hash at *every* byte offset of a file. It is used most notably to do file block matching/deduplication when those matching blocks can be at any offset. It's tragically underappreciated.

I've been meaning to write up a tutorial as part of my Galois Field series. Someday..

Thank you again!

jonhohle 12 hours ago||
I recently found his fingerprint algorithm and wrote a utility that uses it to find duplicate MIPS code for decompilation[0] and build unique identifiers that can be used to find duplicates without sharing any potentially copyrighted data[1].

This replaced some O(n²) searches through ASCII text, reducing search time from dozens of seconds to fractions of a second.

0 - https://github.com/ttkb-oss/mipsmatch 1 - https://github.com/ttkb-oss/mipsmatch/wiki/Identifiers

vlovich123 9 hours ago|||
Important to note that FastCDC is about an order of magnitude for block deduplication and is generally considered the state of art for such an approach (speed of computing the hash is more important than absolutely optimal distribution of hashes).
__MatrixMan__ 11 hours ago||
I'm working on a data annotation system based around Rabin fingerprints. They're a really neat idea.

I especially like how if you end up with hash characteristics that you don't like, your can just select a different irreducible Galois polynomial and now you've got a whole new hash algorithm. It's like tuning to a different frequency.

For me it means I don't have to worry about cases where there aren't enough nearby fingerprints for the annotation to adhere to, I can just add or remove polynomials until I get a good density.

thraxil 14 hours ago||
I took his Introduction to Cryptography class when he was a visiting professor at Columbia. Absolute master of an old-school chalkboard lecturer. They don't make them like that any more.
medina 12 hours ago||
Hugely engaging, the margins of my notebook had many of his quips… there was an archive online somewhere.

e.g., x minus x is zero, even for Euler, so therefore…

Found on Archive, https://web.archive.org/web/20210509160248/http://www.eecs.h...

arbuge 11 hours ago||
I know him from Harvard and came here to say pretty much the same thing. RIP.
ishi 5 hours ago||
I took his Computability class in the Hebrew University. He got angry that students were often late to class, and said that this never happened in Harvard...
ignoramous 3 hours ago||
Any of his "chalkboard" lectures (preferably in English) in open archives of these universities? YouTube searches only bring up Prof Rabin's lectures aided by slides and presentation (ex: https://www.youtube.com/watch?v=thK_qJqx5mo at Tel Aviv Uni / https://www.youtube.com/watch?v=QCX0Ut0hcWw at Harvard).
YZF 2 hours ago||
There's a chalkboard here (used ~44:50):

Cryptography and Preventing Collusion in Second Price (Vickery) Auctions - Michael Rabin

https://www.youtube.com/watch?v=4cmCBVrVQqc

No chalkboard but more lectures

https://youtu.be/nbePExzSTQ0?si=KkTbwfwj5rMtQUhD&t=681 - פלאי תורת ההצפנות ויישומיה לתהליכים פיננסיים (The wonders of cryptography and financial applications)

https://www.youtube.com/watch?v=N_LG5Hcc8mM - Lecture 7 - Zero Knowledge Proofs and Applications Michael Rabin

For those interested in searching for more here's a Hebrew search string you can use: "פרופסור מיכאל רבין הרצאה" interesting enough Google and YT search yield results in English and Hebrew but possibly different ones than just searching in English.

EDIT: One more:

https://www.youtube.com/watch?v=30wkb46BE1k

gchallen 3 hours ago||
I took a course from him as a graduate student. I was not (and am still not) a theoretician. But I enjoyed the class and Professor Rabin's lectures.

A friend of mine was one of his graduate students and a teaching assistant for the class. He pointed out to me once that Professor Rabin would state many of his points during lecture twice. Once I started listening more carefully, I found this to be true. It was both subtle and pedagogically effective.

English was not his first language, but he enjoyed his struggles with it. I remember him stumbling over the pronunciation of a word during class. Giving up with a smile, he said, "This is a word I know only from books."

peterbonney 9 hours ago||
I had the incredible good fortune to take one of his classes in college, and I loved it so much I took another just to learn from him again. A tremendous intellect AND an incredibly engaging and talented instructor. It would be an exaggeration to say that I knew him, but nevertheless he had a great impact on my education and my life. He will be missed.
maxtaco 12 hours ago||
Amazing man, with many important contributions over a very long career. The Rabin Cryptosystem (like RSA, but with public exponent 2) is notable for two reasons. First, unlike RSA, it is provably as hard as "factorization" (as he would call it), and second, unlike RSA, it wasn't protected by patent.
ontouchstart 12 hours ago||
Michael Rabin, 1976 ACM Turing Award Recipient

https://youtu.be/L3FZzGU3n14

ignoramous 1 hour ago||
Michael Rabin: "godfather of Israeli computer science", https://www.ynetnews.com/health_science/article/byohxvw611l
seism 9 hours ago||
That sly remark at 22:40 on the telephone ringing :)
opem 14 hours ago||
It's hard to imagine how a single person managed to accomplish so much. RIP to the great soul :|
tclancy 12 hours ago|
Seriously. After reading, I scrolled through his Known For section and thought, “Alright already, leave something for everybody else to work on.”
adrian_b 15 hours ago||
Michael O. Rabin had important contributions in many domains, but from a practical point of view the most important are his contributions to cryptography.

After Ralph Merkle, Whitfield Diffie and Martin Hellman, Michael O. Rabin is the most important of the creators of public-key cryptography.

The RSA team (Ron Rivest, Adi Shamir and Leonard Adleman) is better known than Michael O. Rabin, but that is entirely due to marketing and advertising, because they founded a successful business.

In reality the RSA algorithm is superfluous and suboptimal. If the RSA team had never discovered this algorithm, that would have had a null impact on the practice of cryptography. Public-key cryptography would have been developed equally well, because the algorithms discovered by Merkle, Diffie, Hellman and Rabin are necessary and sufficient.

On the other hand, while without the publications of RSA, cryptography would have evolved pretty much in the same way, without the publications of Michael O. Rabin from the late seventies the development of public-key cryptography would have been delayed by some years, until someone else would have made the same discoveries.

Together with Ralph Merkle, Michael O. Rabin was the one who discovered the need for secure cryptographic hash functions, i.e. one-way hash functions, which are now critical for many applications, including digital signatures. Thus Rabin is the one who has shown how the previously proposed methods of digital signing must be used in practice. For example, the original signing algorithm proposed by RSA could trivially be broken and it became secure only in the modified form described by Rabin, i.e. with the use of a one-way hash function.

Originally, Merkle defined 2 conditions for one-way hash functions, of resistance to first preimage attacks and second preimage attacks, while Rabin defined 1 condition, of resistance to collision attacks. Soon after that it was realized that all 3 conditions are mandatory, so the 2 definitions, of Merkle and of Rabin, have been merged into the modern definition of such hash functions.

Unfortunately, both Merkle and Rabin have overlooked a 4th condition, of resistance to length extension attacks. This should have always been included in the definition of secure hash functions.

Because this 4th condition was omitted, the US Secure Hash Algorithm Standards defined algorithms that lack this property, which has forced many applications to use workarounds, like the HMAC algorithm, which for many years have wasted time and energy wherever encrypted communications were used, until more efficient authentication methods have been standardized, which do not use one-way hash functions, for instance GCM, which is today the most frequently used authentication algorithm on the Internet.

YZF 6 hours ago||
I think you're vastly underplaying the importance of RSA to cryptography. Personally it was the first time I was exposed to the concept of public key cryptography (in the 1980's). "would have been delayed by some years" is very dismissive. The same thing can be said of many inventions. Yet someone is/was the inventor.

RSA were the first to provide a practical and easy to understand implementation and that had a huge impact in practice.

That's not to downplay Rabin's or others contribution. That RSA pursued a certain commercial strategy that you may or may not like is not really relevant.

tptacek 7 hours ago|||
They didn't really found a successful business. They founded a middling business that didn't do much but license a patent until Security Dynamics, a smart card company, bought them and took over the name.
YZF 6 hours ago||
The story that I remember going around is that they each made some millions of dollars. That was a lot of money at the time for academics. I audited a cryptography course given by Adi Shamir in the early 90's and you couldn't tell he was rich though.
tptacek 5 hours ago||
I mean, I'm sure it turned out great for them, but their reputation definitely isn't rooted in their business acumen.
Ar-Curunir 10 hours ago|||
Nobody has hidden the history of contributions of Rabin to cryptography or computer science.

He is a Turing Award winner.

jonstewart 10 hours ago|||
I would argue that nondeterministic finite automata are both more significant and more practical.
blondie9x 13 hours ago||
[flagged]
adrian_b 13 hours ago|||
This is no AI slop.

On the contrary, you cannot find frequently descriptions about the role of Michael O. Rabin in the creation of public-key cryptography, so few people are aware of it and I bet that no AI model can generate any text even remotely resembling this, because this information cannot be found in any single place in the possible training texts.

You can find definitions of secure hash functions everywhere, but pretty much nowhere you will find who are the authors of the conditions that are used in the modern definition and who have introduced the use of one-way hash functions.

I did not find this information anywhere, before reading the original publications of Rabin and Merkle from 1978/1979 and some later follow-up papers written by them.

You will not find this historical information in Wikipedia and I believe that it is important to know who are the true authors of the things that one uses daily. Connecting to this site or to any other site with https uses digital signatures that depend on the collision-resistant hash functions defined by Rabin and Merkle.

The Wikipedia article about Michael O. Rabin lists many of his achievements, but all those that are listed there are much less important than his contribution to the definition of the one-way hash functions, which lead to secure digital signatures.

Wikipedia mentions only the Rabin signature algorithm, but that has negligible importance, because it has been used only very rarely. On the other hand all other signature algorithms are based on the work of Rabin, by using secure hash functions.

Findecanor 13 hours ago||||
I don't think that is AI slop. adrian_b often post long posts because he thinks he has a lot to say, but you can often tell that they contain his personal views and points that he thinks are important related to the discussions whereas actual AI slop tends to be bland and generic.
d-cc 12 hours ago|||
I wouldn’t really call that AI slop. Some people just write longer posts because they’ve got a lot they want to get across, and you can usually tell it reflects their own opinions and what they think matters in the discussion. Actual AI-generated stuff tends to come off more generic and lacks that personal angle.

I really enjoyed reading it.

sidcool 12 hours ago||
Doctoral advisor - Alonzo Church
eranation 10 hours ago|
TIL. Also just realized that Alan Turing was also one of Church’s doctoral students. We stand on the shoulders of these giants.
snitty 13 hours ago|
May his memory be a blessing.
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