Vervious

We should still expect retail to be alive and well in cities, where people aggregate. The JP Morgan Chase institute report cited by [1] looked exclusively at the impact of WFH and covid. With the pandemic now "over", we should expect SF to bounce back, as did NYC (which now has fewer retail vacancies than pre-pandemic) and many other cities.

In particular, NYC feels incredibly vibrant right now, more-so than pre-pandemic. Maybe it's because of tourism, which is at 110% of pre-pandemic levels. In comparison, SF feels like it got left behind.

That’s a different argument, though. And it’s a hard argument to make; nowhere in the Constitution does it say “Justice for wealthy people only.” The intent of the Justice system is not nefarious; it merely exists to enforce the law.

I reject the vibe that “law enforcement bad, freedom good, tear it all down.” It is not at all constructive or thoughtful. I fear that people are forgetting that everyone is really on the same side, that we do really want to prevent crimes, and fairly and equitably. It’s ok to want a more fair and equitable Justice system, but in my opinion the solution is not to attack every law enforcement action with emotionally charged language.

You say the intent is different but don’t show why. What about obfuscation implies malicious intent? How come it doesn’t apply to encryption?

It can’t be about applications, because I can come up with a thousand applications for obfuscation with benign intent. Such as delegating private computation to AWS without Amazon learning my personal information.

For example, we could write a program that hard-codes a secret key, and then signs bitcoin transactions with that secret key, but only if the transaction has value less than 0.5 bitcoin. Then anyone who has the program can sign things of small value on our behalf; if the program is indistinguishably-obfuscated, they won't be able to get any additional information about the key itself, or use it in any other way.

I guess just encrypting the key won't let you use it to sign things.

The code obfuscation that DRM implementations use is not provably secure. I don't think anyone would (or should) hide a bitcoin secret key inside of an obfuscated program. There's no formal guarantee of security.

This work, on the other hand, shows a provably secure construction for obfuscation (assuming that some assumptions about the hardness of various well-studied mathematical problems are true). In other words, extracting a bitcoin secret key from an obfuscated algorithm is as hard as insert math problem here. (This is how all cryptography works; e.g. breaking RSA encryption is as hard as factoring large products of primes.) This paper is special because, for the first time, the hard math problem they use (to build the obfuscation) is "reasonable": they've been studied for decades, and no one knows how to break them. (Indeed, a lot of cryptography is built on top of the same assumptions/problems.)

Thus, we would be surprised if someone extracted our bitcoin secret key from our obfuscated program, because it means they solved some "thought-to-be-unsolvable" mathematical problem. This is a much nicer guarantee than the alternative, e.g. with current obfuscation, where we say "oh, it looks pretty random, let's stick my key in" and then trusting that no one will break it. (That's a lot of trust, when you might have a 100,000 Bitcoin at stake.)

Of course, none of this is really feasible; at best, we can securely obfuscate tiny circuits (in the present time). So the main utility is probably to hide keys and the such, not to obfuscate entire programs. This might enable better secure MPC schemes, NIZKs, etc. So I guess, per your question, it's also targeted towards a different use case.

Now, as to why theoretical cryptographers care about obfuscation in general: it's not so much about the direct application of obfuscating programs. (It's not obvious why obfuscation is more interesting than encryption, etc, from an applied point of view.) Instead, from a theoretical point of view, if we can build indistinguishability obfuscation, we can directly build public key encryption, non-interactive zero knowledge proofs, Multiparty computation, etc. etc. (assuming one-way functions). So really, this is a primitive that somehow connects all of the other primitives, which is why theoreticians think it is a big deal.

I mean, the same argument has been applied to other cryptographic tools. Why encrypt your messages, unless you're sending something sketchy? Why obfuscate programs, unless you're hiding something?

Yet I think the utility of encryption is well-demonstrated, and not just theoretical. It can be used by good people to defend against adversarial intent. And it may well be that obfuscation (in its most direct application) has the same effect. (e.g. companies sharing proprietary algorithms for you to run at home, without revealing the secret sauce; or me delegating computation to AWS without revealing secrets)

Note that this is not why indistinguishability obfuscation (iO) is a crown jewel, here. Practically, iO is nowhere close to obfuscating anything larger than a tiny circuit. But it can still be useful to do things like obfuscate secret keys when designing cryptographic protocols. Theoretically, iO allows us to derive essentially every cryptographic primitive, which is why this paper is interesting, and why iO is called a crown jewel. And now, we can build iO for the first time from well-studied hardness assumptions.

Why? It's not a trash title. Explain yourself, and give us some substance instead of being inflammatory.

Indistinguishability obfuscation (plus one-way functions) implies basically every cryptographic primitive there is, including public key encryption, NIZKs, and MPC. It gets close to giving us FHE (open question, I think). In some sense it is a "unifying primitive". Absolutely a holy grail to cryptographers, even if it isn't for you.

Yeah, I feel like this crowd sometimes forgets that the department of justice exists first and foremost to keep us safe.

With PyPi hosting a ton of malicious packages and malware, certainly I am not morally opposed.

Sorting algorithms are pretty amazing, though.

There are improvements in both performance and understandability.

On the performance front, see Algorand's consensus protocol (2016 ish), which can run on 10,000s of nodes, using a cryptographic technique called "sortition" which sub-selects a small committee of nodes to actually broadcast messages of the consensus protocol.

On the understandability front, this is my research area; we put out a new protocol recently (https://eprint.iacr.org/2023/463) that is faster and much easier than PBFT (and crash fault equivalents like Paxos/Raft). But there's a long line of prior work here.

Traditionally, consensus (PBFT,Paxos,Raft) has run on a small set of nodes (i.e. a dozen) and also has used what are called "stable leaders", where a single leader process sequences all transactions until it is detected to be faulty. Stable leaders are great for data centers.

Blockchains made it so that now protocols support thousands of nodes, and also use "rotating leaders", where a different node proposes each block (for fairness reasons). It happens that using rotating leaders allows for simpler protocols (in particular, with easier proofs).

There's a lot of new results in cryptography/distributed algorithms, motivated in part by applications to blockchains. But even if you don't believe in blockchains they are interesting.

  - better zero knowledge proofs/arguments
  - better consensus protocols (my expertise!)
  - multiparty computation is nearing practicality, as is fully homomorphic encryption

Also, lots of fascinating theoretical progress on primitives such as indistinguishability obfuscation, post-quantum schemes, quantum crypto, etc.

No no no no no it'll run it to the ground like the USPS, or, gasp, the Israeli postal service (which, coincidentally, also lets you open bank accounts). (We actually have it super good in the states with door to door package delivery. It could get so much worse.)

This could be a cool domain for LinkedIn to move into —— allow reviews only from people who publicly list the company in their profile

Though, P and NP are intrinsically defined asymptotically, so I'm not sure what it means for P != NP for all practical problems, other than saying that something like 80*n^5 is impractical to compute for n=10000, say.

Btw, I think technically if the car is locked, it's also classified as a burglary

A ton of people care about property crime and I don't think you should look down on them.

SF has 3-5x the property crime of most major cities in the United States. I imagine most violent crime is targeted (i.e. the victim is not a random person walking down the street), but property crime is scary because it can happen to the best of us, our friends and our family, in even the "safest" neighborhoods. We all know friends whose cars have been broken into. And it's easy to imagine --- what if my kids were at home during one of these home break-ins? (Note that burglaries are not classified as violent crime in SF)

SF rent is pretty equivalent?

And note that SF spends $604 on policing per resident, vs NYC's $626 on policing per resident

That's only because SF isn't safe, esp relative to rent price. I regularly walk alone at 2:30am in nyc in most neighborhoods.

Big +1 to you.

It’s not every day that a big tech exec gets stabbed and killed. It’s like a bank exec getting mugged in nyc, it just doesn’t happen.

it's actually a very open question, even theoretically, whether we can build an "hard on average problem" from a "worst case hard problem" in NP. This is why we haven't yet managed to design cryptography from 3SAT, for instance.

I'm confused, what are the takeaways, and why are there 83 upvotes with no discussion?

We have statistics to talk about this sort of stuff. And Twitter revenue, whilst a fraction of that of Meta, is growing, and is currently $5B/yr.

To put things into perspective, Tiktok's revenue is only 2x of that of Twitter's, $10B/yr. Clearly Twitter gets enough eyeballs (like mine) that people want to pay for it.

There are a number of mature and thoughtful communities on Twitter.

For example, the academic community - from theoretical CS to systems to healthcare to biology to economics. I think probably 1/3 of faculty at top universities under the age of 40 have a twitter presence and tweet very useful things.

I have also found the journalistic and sports sections of Twitter to be very useful. For instance, where else does one get the latest football injury news, or line changes made on the san jose sharks?

And honestly, with how successful 9-9-6 culture has been in other parts of the world, maybe he's right and you can actually run a successful software enterprise without a corresponding bump in compensation. It makes a lot of sense if he can pay engineers less and still maintain the product.

There’s no verified journalists or faculty or domain experts, etc, on Reddit.

What an impotent philosophy. The world moves on from everything. Why bother stalking hacker news if this is not the sort of thing that interests you?

The half billion monthly active users and $5B annual revenue beg to differ. And it trickles down in the form of paychecks — does that matter?

Is it mostly engineering or other roles being laid off?

I want that. I think that refusing to fix a life-or-death bug for 8 months is criminally negligent. Especially when millions of Pixel 6s are out in the wild, as an essential utility for millions of people.