The Limitations of Intelligence - <AUTHOR> https://www.schneier.com/blog/archives/2013/09/the_limitations.html

<comment><USER2> On the topic of the agencies' own success criteria: Schneier theorizes that NSA measures "by amount of data collected". While he declines to speculate as to the CIA's criteria, he suggests that their surprise at the end of the Cold War was not to their credit.

I think this is a misunderstanding. Any agency of the federal government measures success first and foremost by the volume of federal resources it consumes, and by the swelling of that volume over time. This priority is seldom articulated, and it isn't as though the "real" mission is ignored, but the structure of the organization and the incentives to which its members are subject make it obvious. To take the example of the NSA, their commitment to _copy all the data_ is really a commitment to maintain their size at a fixed ratio with a quantity that will grow indefinitely.

Some might say this is a failing of the system, but it's enough to just recognize it as a property of the system. If we want the federal government to do a job, it usually will, but its performance will have this grow-spending- always, mission-as-afterthought quality. That isn't too terrible when the job at hand is redistributing wealth among the citizens: at least there's a chance that the progressive and regressive impulses will cancel out. When the task is actively destructive to the nation and the world, however, the organization must be controlled in some manner. No such entity will limit itself.

We are equipped to curb the excesses of e.g. the Department of Agriculture. However, the "secret" agencies have gotten a free pass from public scrutiny for 75 years. The answer to the dilemma is to end the culture of secrecy. No action of the USA government should be concealed from its citizens. There will be trade-offs involved with switching to this policy. Certain operations will be difficult or impossible when they can't be hidden from view. Those operations are typically counter to the long-term interests of the American people anyway, and the sooner they are stopped the better.

The unsavory, if still limited, view we have now of the actions of these agencies, speaks not of a failing of those agencies, but of our failing to understand their basic nature, and govern them accordingly.

<comment><USER3> Highly incorrect. NSA success is measured through a reporting system that tracks which reports are cited in other reports, and which reports get used in briefs (and the relative level of brief). This mechanism is used to determine the relative importance (funding) of certain functions, and used to cull functions that are not ultimately reportable. The ultimate say-so in targeting comes from the administration, based on what information they're most interested in.

<comment><USER2> So there is a possible future in which the President, his advisers, and others in the executive branch throw out so many reports and briefs as "useless, not worth the paper to print" the stench of ineptitude so overwhelms the NSA brass that they spontaneously decide, themselves, to stop building in Utah and not _collect all the data_?

Yeah, right. Pull the other one. Next you'll tell me an incumbent chief of police has realized the folly of The Drug War.

</comment></comment></comment><comment><USER4> Let me say first that I am a technologist and I do have generally speaking an optimistic view of the future where technology actually solves most of our problems. I believe in the concept of the singularity where super-intelligent AI makes human intelligence irrelevant. I have a completely different worldview from almost everyone reading this thread so what I am about to say will probably just be dismissed as "conspiracy theories" or something but I need to say it just in case some people may be able to get something out of it without dismissing it out of hand.

Its going to be difficult for anyone who routinely exposes themselves to mainstream news sources to see any of what I am about to say as being credible. Especially in the tech community where rose-colored glasses are almost ubiquitous.

He wonders why they didn't stop the Syria chemical weapons attack and the Boston one. The reason is that those were false flag attacks. The Syria attack was committed by US-backed rebels and then blamed on the regime in order to be used as propaganda to motivate the extension of the covert proxy war in Syria into an overt one involving the US forces directly.

The Boston attack was used to motivate gun control which is important for securing the state against dissident factions when the economic situation deteriorates dramatically as it is likely to at some point when a substantive challenge to the petrodollar status is mounted.

Back to the war in Syria, I urge everyone to take a look at some maps of the middle east and Africa and make an X in all of the countries where the US and allies or related countries have been involved in recent decades (centuries). You will see that this is a long term military campaign rather than a series of isolated wars. Also take a look at a list of countries by proven oil reserves. Also look up 'petrodollar'.

[http://www.indymedia.org.uk/images/2007/01/359290.jpg](http://www.indymedia.org.uk/images/2007/01/359290.jpg)

The Afghan War should be considered the Third Opium War as it was largely motivated by the Taliban wiping out the heroin cash crop belonging to the Anglo establishment and intelligence agencies. [http://publicintelligence.net/wp- content/uploads/2012/11/Afg...](http://publicintelligence.net/wp- content/uploads/2012/11/AfghanOpiumSurvey2012-1.png)

The purpose of the NSA is not to control terrorism. It is to keep tabs on potential enemies of the US, both domestic and foreign. All US citizens and foreigners are actually considered potential enemies of the state. The closest thing for people to understand is to compare it to the East German Stasi. This type of apparatus may seem unnecessary now while the US is fat, happy and sitting pretty, but like I mentioned, the petrodollar cannot continue forever, and the state knows that. Economic conditions will some day change very dramatically and lead to large-scale hunger, and at that time the previous removal of citizen's arms and vast surveillance network will make the state much more secure in the face of growing domestic dissent.

Of course since most people have a totally different world view and are constantly bombarded by propaganda on television, this will all just seem like nonsense to you.

</comment><comment><USER5> I know it's sort of orthogonal to the point Schneier is making, but to my mind, many of his suppositions relating to Syria are off. I don't think doing preventative strikes even if we knew Assad was about to gas hundreds of civilians were on the table. That logic--prevention--was used in Libya and it has rightly fallen out of favor with the Obama administration, mostly because Libya has proven to be a real shit-show. In any case, attacking before a crime is committed is a dangerous precedent to set on the world stage, a recipe for perpetual war.

The limits of intelligence are real, but the Syria example is not the best one to use to illustrate the point.

<comment><USER2> _...mostly because Libya has proven to be a real shit-show._

Did rational people expect otherwise? Fool us once, shame on the military- industrial-media-lobbyist complex. Fool us seventeen times...

</comment></comment><comment><USER6> > I don't know how the CIA measures its success, but it failed to predict the > end of the Cold War.

The answer is obvious -- the end of the Cold war hinged on the end of the USSR, and the end of the USSR was not a matter of intelligence, but broad historical forces and chance. If the CIA had had perfect field data, it still wouldn't have predicted the end of the Cold War, because the Russians didn't see it coming either.

This wasn't an intelligence failure, because no one had the required intelligence.

<comment><USER7> I agree, and would add that the mission of the CIA is to assess foreign threats to the U.S.

The end of the Soviet Union was not a threat to the U.S., thus predicting the exact date of its occurrence was not a priority.

<comment><USER8> The sudden end of the Soviet Union was a _massive_ threat to the United States.

The Soviet Union was a regime that by the 1980s had amassed a stockpile of tens of thousands of nuclear weapons, which were stored and deployed across the vast interior of the USSR. The regime was the only guarantor of the security of those weapons. A breakdown of the regime would (and did) throw open the question of _who now controlled those weapons._ A new successor state? Individual breakaway republics? Factions within the army or internal security forces? Non-state actors? Random locals who happened to show up at a silo with a big enough mob behind them to claim them?

The USSR also had huge conventional forces stationed across Eastern Europe, Asia and Africa. If the authority these forces reported to were to suddenly break down, how would they respond? Would factions among them split and fight each other? Would a general use his tanks to set himself up as King of Poland? Would a revanchist politician rally the army to establish a military dictatorship?

With hindsight we know the answers to these questions, but at the time we did not. Which is why intelligence agencies exist -- to help answer them.

Thanks to quick thinking and quick action by both Americans and Russians (and Ukrainians, and Belarusians, and Kazakhs, etc.) in the years following the dissolution of the USSR, Soviet conventional and nuclear forces were (mostly) secured. (See [http://www.washingtonpost.com/wp- dyn/content/story/2009/09/2...](http://www.washingtonpost.com/wp- dyn/content/story/2009/09/20/ST2009092002315.html) for an example of one story from that time.) But there were no guarantees at the time that things would turn out as well as they did. So the question of whether the USSR was breaking up _should_ have been of urgent interest to the CIA, because a breakup that went bad could have had catastrophic consequences for the US and the world.

<comment><USER7> That's a great point and I did not think of it that way. Thanks.

</comment></comment></comment></comment><comment><USER9> I think it is worth reviewing the "Schneier Doctrine" as I understand it:

Principles

* Security is a trade off between safety and freedom / cost

* Prevention is not always the most cost effective trade-off. Emergency response is often better.

* Stories make a huge difference in how humans perceive threats around us - and can therefore make a difference in correcting the perceived threat model to match the actual threat model.

Doctrine (not sure he has ever voiced these...)

* Define National Security quantatively (less than 1,000 expected deaths, or loss of less than 1% GDP its not national security). If someone slaps a National Security Letter on you today, its laughable, if personally threatening. If they slap a NSL on you _when that means they seriously think a 1,000 people could die if you do not comply_ its not laughable.

* Massively increase spend on post-event support (ambulance, decontamination).

* Run public security "games" where teams of experts kill as many of us as possible using only items found in CostCo. (Trying to reframe the perceived threat model to meet the actual threat model). Simon Cowell could present it.

<comment><USER10> You're basically correct about his principles, but I feel like your post makes it sound like Schneier's just trying to save money and doesn't care about the actual lives involved.

I think an important point is that it is literally impossible to prevent all crime. Not only is it impossible, but as you try harder and harder to prevent it, you get diminishing returns _and_ an increase in false positives (which we also want to avoid). So yeah, there has to be a tradeoff. If you can't ever get the number of deaths down to zero, then you have to decide, how low is close enough and how much are you willing to sacrifice to get there?

Right now, we're sacrificing a crap ton, and it's really not clear that it's gaining us all that much.

<comment><USER9> I beleive Schneier does care and was not intending to come across as belittling such things. Despite the Chuck Norris meme I am sure he is as human as the rest of us :-)

Its just we do live in a world where somehow we must efficiently allocate resources. In the UK we use a term QALY (Quality years of life) which is used to decide between which operations should go ahead (likelihood of success x expected number of qualifty years) - so a 80 year old looking for kidney dialysis is lower down the list than a youth looking for a common hip replacement. The US does it simply on income.

We should I feel have a debate on these things - why is it cars can kill thousands but a cancer drug cannot kill one or two. These trade offs get made in odd ways - and while I doubt we shall ever have politicians campaigning on the slogan "vote for me, only a tiny percentage of you will die because of it" its an important discussion.

I would suggest also a poll taken in the security / check-in lines at JFK:

      Would you support allowing one major terrorist outrage
      a year if it would reduce queueing at airports by

      a) 1 hour,
      b) 2 hours
      c) eliminate queues completely?

:-)

</comment></comment></comment><comment><USER11> Who assumes that what the intelligence report says now is actually based in fact and not in convenient fiction? The US poised to attack Syria -- having long supported the opposition -- and the stars needed to align to help that happen. For a released intelligence report to yield the very strongly desired results, among a collection of agencies with a long history of bending the truth (patriotic so long as it served the end goal), should be met with a hefty serving of skepticism.

<comment><USER12> Totally agree, Call me a cynic but Schneier doesn't mention the possibility that the administration knew they could have effectively prevented their use but they don't really care that much about chemical weapons or the people of Syria. In fact, they may have seen their use as a political opportunity to provide justification for furthering American interests in the middle-east.</comment></comment>


Committing like Crazy - GitHub - <AUTHOR> http://github.com/blog/620-committing-like-crazy <comment><USER2> Github > Google Code > Sourceforge

On checking out/exporting:

I had to use Sourceforge a few weeks back: some project I needed the code to was hosted there. I'm not a stupid person, but it took me several minutes to figure out how to grab the source code to the project.

Google Code, in contrast, still makes you jump through a couple hoops.

With Github, it's a simple matter of clicking the little clipboard button (which I think should be bigger), switching over to my terminal, typing git clone and pasting. Easy, simple, fun. Just the way it should be.

On the social aspects of open source:

I have absolutely no idea who the people are that are involved with Sourceforge projects. I'm not sure why they're still using CVS. I'm not even sure I have CVS installed on my laptop (update: turns out I do. Snow Leopard ships with it. Who knew?). I have no desire to join a project.

Google Code is better. At least I can easily figure out how to post an angry comment to a project wiki. But who knows if a given project is still in active development without digging into the commit history? (Click Source, Click Changes. Oh great, the project's dead.) It's a pain to figure this out, especially when I eventually find a link buried somewhere informing me that the project maintainer has moved themselves over to Github.

Github tells me exactly what I want to know as soon as I get to a project page. When was the project last updated. Who's involved in it? How many people find it interesting? How many people find it interesting enough to fork it?

Sourceforge was relevant back when I could say the same about Slashdot. Google Code was fun for a year. I'm glad Github is as big as it is now. To reiterate another commenter, I really hope they never get acquired by Google.

<comment><USER3> You're calling clicking twice a pain?

If the project maintainer has moved to Github and doesn't post this prominently, it's hardly Google Code's fault, isn't it?

<comment><USER2> I am calling clicking twice a pain. There is a lot of useful information that Github surfaces on main project pages that Google Code and Sourceforge do not.

There's no reason why Google Code's very sparse right information column should not be supplemented with a 'last activity' row.

</comment></comment></comment><comment><USER4> Some of these differences in numbers come from how git works in general.

A push is basically just uploading your repository to the remote server. As such a push might contain many commits by the person who pushes and others by different people - many of which are also part of other pushes.

Also due to the decentralized model of git and the model of pulling code from other people, it's highly likely that some (most?) of these pushes/commits never end up in the official repositories of the different projects.

Pushes may contain commits to throwaway branches, to branches for private use.

Also, the blog post doesn't say anything about rebases. If I push a rebased private branch, it will contain all the commits of the branch but with changed IDs.

There are so many more occasions for a commit to be moved around over the network in git than there is in the more centralized solutions as they are provided by Google Code and Sourceforge.

Yes. Google Code does provide Mercurial, but it's still project centric. So what gets committed to google code is official code that is part of that projects code base.

What gets commited to github is mostly throwaway stuff or patches about to be processed before being merged into some mainline.

This is where the difference comes from. It's just natural.

</comment><comment><USER5> Github is a full-on game-changing company. They seem to be doing most everything right.

By charging developers money to host non-free projects, they've aligned their interests with developers: their customers. This means you get a no-bullshit interface which is exactly what I want from my project hosting.

I pray that google doesn't buy them.

<comment><USER6> From conversations I've had at their drink-ups, I get the sense they're pretty disinclined to sell the company, for reasons of personal freedom. Naturally, enough money will tend to push that sort of thing aside. I just don't think they're actively looking to get bought out, unlike some.

</comment></comment><comment><USER7> Part of this has to be a Git vs SVN. (I know that Google Code supports Mercurial, but I believe all project I'm subscribed to use SVN.) But I commit and push way more with Git than I did with SVN. Probably twice as often. I usually commit every time I write a function or even a loop. I usually push whenever I've fixed a case in the bug tracker.

With SVN, I used to only commit once I fixed a case.

<comment><USER8> Really? I do the opposite. You can't commit at all without hitting the server in SVN, where I can go for quite a while in Git without pushing. I would assume that most people would push in Git much less often then committing in SVN. It's obvious that because the commits are faster, they would commit more - and they are (109,000 Git commits over 33,154 pushes vs 17,000 svn commits). So in Git people commit on average 3 times before they contact the server.

<comment><USER6> Pushing to a public repository (especially forks of ones people actually care about, but this is true in general) gives me a small feeling of accomplishment. It's a way of sharing that I did something I think is useful, especially since it shows up in the news feed of my (handful of) followers.

So yeah, I probably push more often than is strictly necessary.

</comment></comment></comment><comment><USER9> A lot of repos on GitHub are clones of popular projects hosted somewhere else. I doubt many people import svn repos on Google Code in a similar fashion.

<comment><USER10> I may just be stating the obvious, but I think this is because git is decentralised and SVN is not.

If you fork a git project, your clone is just another branching point in the DAG that represents the "universe" of commits across all repositories.

SVN on the other hand does not support branching naturally. It's as if the branching never happened, and there always were two separate repositories.

I think this is why SVN users often avoid branches. SVN can make them, but it does nothing to help developers _merge_ their branches.

</comment></comment><comment><USER11> I think the easy interface of GitHub is because it was made to just work. No bullshit git functionality, which led to a fine product which everyone wants to use.</comment>


Hoard: Distributed Data Caching System to Accelerate Deep Learning Training - <AUTHOR> https://arxiv.org/abs/1812.00669 <comment><USER2> This doesn't seem like they actually provided and/or did anything new here. (Hard to tell cuz there is also no obvious code. Is it just cachefsd?)

About a year and a half ago I did something similar with essentially the exact same hardware.

BeeGFS filesystem across x3 IBM power8 Minksy's with NVMe drives for distributing data quickly, in parallel, and effectively across multiple machines. Really helped with the scripting of a batch job as the file system was unified across the platform and had some good in memory caching.

I have the numbers somewhere but I felt like theirs aren't really that great considering 40gbps mellanox & NVMe. Should really be able to get quiet a bit better throughput. Also ran thousands of jobs and many Tb of data. Not just 24 over gigabytes.

(FWIW I didn't thoroughly read the actual article that thoroughly.)

</comment><comment><USER3> Has the code for this been released at all? I've gone through the paper and can't seem to find it.</comment>


The Ins and Outs of the Abandoned Cart - <AUTHOR> http://www.permuto.com/blog/2010/06/17/the-ins-and-outs-of-the-abandoned-cart/ <comment><USER2> Cool graphic. It's definitely worth studying, but I disagree with counting the value of abandoned carts as "lost" revenue.

Instead I think this is a case of the online shopping cart being viewed too much like its real-world equivalent. Adding items to a cart online may be closer to bookmarking than to purchasing (another reason is to reveal the cost of items with hidden pricing, as is practiced on Amazon).

<comment><USER3> I was experimenting with Amazon's implementation of this recently (having had to honor lame MAP pricing when I did internet retail websites), and it's interesting that it's merely behind a click, it doesn't actually add it to the cart and then have you remove it. The wording is just that it's been added and is in your cart.

</comment></comment><comment><USER4> Some retailers require you to start the checkout process find how how much shipping (and possibly tax) will cost. When I am shopping around for something, I'll often go partway through the checkout process just to get a cost I can compare with other retailers.

Even worse, some retailers (occasionally Amazon) require you to add something to your cart to see the sale price, which presumably they aren't allowed to "advertise."

I'd bet that very few of these lost sales are really lost sales. Either some other retailer got the customer's business or the customer decided not to purchase from anywhere.

</comment><comment><USER5> Maybe if you'd show me shipping charges when I select the item this would be less of a problem. Although odds are that just means I won't even add the item to my cart.

<comment><USER6> most shipping rates are based on where you are located. So the retailer at least needs to know your zip code before you will get accurate shipping rates

<comment><USER5> Geo lookup for the win.

<comment><USER6> geo lookup isn't that accurate yet (I assume you are talking about geo-IP lookup).

</comment></comment></comment></comment><comment><USER7> I've heard of people filling physical carts with (non-perishable) goods and abandoning them in the store to protest against a supermarket chain. This makes me wonder whether a similar online tactic might be effective.

</comment><comment><USER8> Totally agree with the past comments. This graphic exaggerates the impact of abandoned carts with misleading conclusions.

In the end, adding items to a cart is no different than viewing an item's page (imagine the billions lost through "abandoned" page views!).

That said, it's still helpful. Permuto highlights the reasons behind cart abandonment. It's essentially a list stuff retailers should properly convey to their customers way before check out.

</comment><comment><USER9> This is tangentially related, but when I lived in Palo Alto I'd walk past the Permuto ("The Shopper Connect Network") offices every day (the corner of College Ave and Staunton Ct) and always wondered what they did, exactly.

Some sort of B2B e-commerce and analytics company?

</comment><comment><USER10> agree with comments here that this is not real lost revenue - its mostly online window shopping - however on your ecommerce retail site we put flat rate shipping cost on the product page to entice people to buy and give them that crucial info upfront. also there is a typo on the infographic - it says US population is 309.5 Billion : )</comment>


Ask HN: Will I be allowed to do this? - <AUTHOR>

I had an idea that I am trying to vet and I have some major concerns.
While posting a comment on a news article the other day, I chose to use twitter authentication to log in. Of course, the newspaper website wanted to have access to my tweets, my followers, and the ability to post new tweets on my behalf, none of which I was comfortable giving up just to post on a random news article on a random site. I imagine that this prevents a lot of other people from posting as well.
I am considering creating a new authentication provider that will allow users to authenticate via their twitter, facebook, or google+ accounts, while not allowing any of the invasion of privacy that comes with using the standard OAuth providers.
My concern is that this will be deemed as some form of competition by the respective services and they can simple cut me off and kill my authentication service.
Your advice is greatly appreciated. <comment><USER2> I think you will need to make a decision as to whether you are hoping to serve as a proxy login (you log into me with twitter ; i log into them on your behalf) or to have a separate standalone service that's clearly demarcated from the host publisher.

I believe you'll find the former is challenging. It would be against the TOS of most authentication providers to do this as an arm's-length intermediary. I think you could do it as the contracted agent of the publisher (which implies a white-label approach). See, for example, the way JanRain works.

The best examples of the latter I can think of are Disqus, Echo, et al. You might want to check them out.

<comment><AUTHOR> Greg,

Thanks for the reply. I was thinking to have a standalone service that is clearly demarcated from the host publisher. I wouldn't store passwords, I would simply serve as an authenticator for websites that would use the service as an alternative to the standard oauth provider from twitter or facebook, etc. The issue is that I would probably have an app on their ecosystem to facilitate the process.

BTW, brnr.me sounds like a great service.

<comment><USER2> thanks!

</comment></comment></comment><comment><USER3> I liked the idea of Mozilla Persona ([https://www.mozilla.org/en- US/persona/](https://www.mozilla.org/en-US/persona/)), but that doesn't seem to be catching on.

I think you're on to something though, there are a lot of sites that want access to far too much, as if the developer cut-pasted all of the scopes they could find.

<comment><AUTHOR> Thanks for the reply. Given that persona does not have traction then I would guess that the hard part would be getting sites to use it. I would expect that there would be high demand for a service like this, but perhaps privacy is not as important to some as to others?

</comment></comment><comment><USER4> As Richard Branson said; Screw it, just do it.</comment>


To clean the air, Dutch scientists invent pavement that eats smog - <AUTHOR> http://www.latimes.com/news/science/sciencenow/la-sci-sn-smog-eating-street-20130705,0,4941635.story

<comment><USER2> Some napkin math:

There are ~2.5 million miles of highways in the United States, for the sake of easier math and a lack of statistics let us assume that this length of pavement is responsible for all of the vehicular nitrous oxide emissions.

Transportation contributes 30% of total NOx emissions [2]. Lets assume that the average highway is 4 lanes wide, giving a width of 62 feet.

Surface area = 2.5 million miles * 62 feet = 29 356 square miles.

The authors add 2.67 g per square meter of C-doped TiO2 (which has a lowball estimated cost of ~$750 per metric ton.)

This gives us 203 000 tonnes or ~$150 million. This has to be applied 3x a year (at least) to maintain ~%60 of maximal effectiveness of the TiO2 (20%) over the year.

A generous estimate is that it is sunny ~1/3 of the time.

So to bring it all together, $450 million of raw materials would result in a (1/3 * 60% * 20% * 30%) 1.18% reduction in NOx levels.

[1] Original Article: [http://dx.doi.org/10.1016/j.jhazmat.2013.02.012](http://dx.doi.org/10.1016/j.jhazmat.2013.02.012) (behind a paywall) [2] [http://epa.gov/climatechange/ghgemissions/gases/n2o.html](http://epa.gov/climatechange/ghgemissions/gases/n2o.html)

Edit: Updated math, I used the wrong percentage of the contribution of motor vehicle traffic, the correct figure is 30%, nevertheless the conclusion that this would be a colossal waste of money still stands.

<comment><USER3> The TiO2 is not picky, it will also catalyze NOx from different sources, not only cars.

<comment><USER2> Not exactly, manufacturing plants release emissions very high into the air. To my understanding the pavement has an effective radius of < 150m (from the article).

</comment></comment></comment><comment><USER4> The title is a little misleading. Titanium dioxide has been known since 1967 [1] to act as a catalyst for oxidizing a wide range of compounds, including nitrogen oxide (i.e. smog). Since at least 2002 it has been known to significantly decrease smog when applied to road surfaces [2][3]. The contribution here is another study (behind a paywall [4]) providing evidence for TiO2's efficacy at reducing smog.

[1] [http://en.wikipedia.org/wiki/Titanium_dioxide#Photocatalyst](http://en.wikipedia.org/wiki/Titanium_dioxide#Photocatalyst)

[2] [http://www.italcementigroup.com/NR/rdonlyres/1F30E487-C0A2-4...](http://www.italcementigroup.com/NR/rdonlyres/1F30E487-C0A2-4D6F-AB6D-C14555FD866F/0/Scientificresults.pdf)

[3] [http://www.time.com/time/specials/packages/article/0,28804,1...](http://www.time.com/time/specials/packages/article/0,28804,1852747_1854195_1854176,00.html)

[4] [http://www.sciencedirect.com/science/article/pii/S0304389413...](http://www.sciencedirect.com/science/article/pii/S0304389413001210)

<comment><USER2> This paper is about carbon doped TiO2, its synthesis was patented in 2005 and is much more effective than regular TiO2.

<comment><USER4> _carbon doped TiO2_

Can you provide a reference? Did I link to the wrong paper? That's an important detail and it's not in the article.

 _much more effective than regular TiO2_

How much more effective? The study done by Italcementi in 2002-2003 (admittedly not very trustworthy since it's done by the company that makes the product) has numbers comparable to the Eindhoven study.

<comment><USER2> _Can you provide a reference? Did I link to the wrong paper? That 's an important detail and it's not in the article._

I'm not sure if you can get past the paywall but:

Section 2, paragraph 4, last sentence. "Carbon doped TiO2 from Kronos International was used."

 _How much more effective?_

It varies from 2x-10x depending on the reaction conditions. Here is a paper that shows 2x-4x based on a relatively primitive doping technique.

[http://dx.doi.org/10.1016/j.apcatb.2007.09.046](http://dx.doi.org/10.1016/j.apcatb.2007.09.046)

 _Italcementi_

Their TX Active may or may not be carbon doped, I couldn't find a straight answer on their website. Self-cleaning TiO2 is almost certainly doped (Ag or SiO2).

</comment></comment></comment></comment><comment><USER5> Seems like a cool idea but I'd be worried for the workers who have to dig up the pavement as titanium dioxide dust is classified as potentially carcinogenic. Perhaps the quantities in use are very small?

</comment><comment><USER6> I read years ago about a car grill coated with something that also "ate smog", but I guess cars don't have grills anymore or the project failed for some other reason.

</comment><comment><USER7> Seems like the Technical University of Eindhoven is the place to be these days.

</comment><comment><USER8> This is one of those inventions where if Daoist thought comes in to play it allows you to laugh heartily at the folly of the entire proposition.

Observe: (1) The further you go from nature, the more problems you cause yourself. (2) Concrete industry is one of the greatest polluters in the world. (3) The impermeable nature of concrete is at once its weakness; by attempting to block nature's course, it ensures both its own destruction and engenders other problems such as flash floods. (4) Given the above, why make a new concrete to 'improve' upon nature? Nature cannot be improved upon. Because there is only one Way. (5) The Way that can be written is not the Way.

<comment><USER9> > (4) Given the above, why make a new concrete to 'improve' upon nature?

Smog-eating concrete isn't improving upon nature, it's improving upon not- nature (which concrete clearly is according to points 2 and 3), thus bringing it back closer to nature, and reducing the number of problems you cause yourself, per 1. So, if you must build a Way, at least build it out of smog- eating concrete.

<comment><USER8> I wonder what famous Dutch hydraulic engineers and their environmental science counterparts would say about removing natural water absorption in favour of promoting runoff over chemical-laden surfaces. Similarly, I wonder if we shouldn't look at such substances from the perspective of the overall energy expended on their production, installation, maintenance and eventual disposal over time.

<comment><USER9> The question isn't concrete vs. some environmentally friendly surface, the question is concrete vs. smog-eating concrete, and whether the smog-eating concrete is more environmentally friendly than regular concrete. Yes, total cost to the environment over time is a consideration here.

<comment><USER8> If you choose to artificially limit your scope of thought, then by all means go ahead. However, any conclusions based upon such thinking will be similarly limited. Personally I find more interest and utility in analyzing the potential interactions of things on a broader scale.

There is some parallel here in conventional computing wisdom: _measure twice cut once_ dictates that, given limited time, you're better off thinking a course of action out before investing effort in creating something requiring an ongoing investment of effort.

Thus, if the scope for this type of invention is environmental quality, why not consider overall energy use and knock-on effects as part of your evaluation?

<comment><USER9> I believe I just wasn't clear. In my first sentence I was clarifying the discussion - we agree that no concrete at all is best if possible. In my second sentence I was agreeing that it makes sense to consider energy use before rolling out the supposedly greener concrete.</comment></comment></comment></comment></comment></comment>


What to expect from Netflix first quarter earnings on Monday? - <AUTHOR> https://news.alphastreet.com/what-to-expect-from-netflix-first-quarter-earnings-on-monday/ <comment><USER2> $330 after earnings</comment>


Ask HN: Why is Firefox installer listed as harmful file in Chrome? - <AUTHOR> Example: https://imgur.com/a/XMeiO4D
Is it only me? Is something is wrong with Firefox installer?
I'm trying to download Firefox from official mozilla website and Chrome says that the file is harmful. For reference it's not the .dmg extension because if I go to Chrome and download googlechrome.dmg it gets downloaded without any problems. <comment><USER2> Well, it is harmful for Google.

</comment><comment><USER3> Chrome often list executable files as harmful IFF they are downloaded via HTTP instead of HTTPS.

</comment><comment><USER4> Like the old adage : "Excel isn't done until Lotus won't run.'

<comment><USER5> Nonono, you've got the saying wrong. It was " _DOS_ isn't done until Lotus won't run."

The old Microsoft wouldn't bother competing at the app level if they could just kneecap the competition at the platform level instead.

</comment></comment><comment><USER6> US English Firefox for mac OS looks pretty clean, according to VirusTotal: [https://www.virustotal.com/gui/file/d0bd62e9b57062e3cb04ac05...](https://www.virustotal.com/gui/file/d0bd62e9b57062e3cb04ac05444ba3856d2c1fc5d4f079eb4233a3053d1c1bb5/detection)

I wonder if Chrome is including the Mac sandbox, which is listed, in its decision to label the installer as unsafe?

</comment><comment><USER7> I wouldn't be surprised if it is based on the extension, with exceptions for some specific trusted domains/downloads

</comment><comment><USER8> > For reference it's not the .dmg extension because if I go to Chrome and > download googlechrome.dmg it gets downloaded without any problems.

That doesn't mean it's not the extension, as they may have somehow whitelisted their own files. I would expect that warning to come up with any file format that can carry executable code.

</comment><comment><USER9> I just tested and I got warnings for neither file. Maybe they warned you for the first .dmg, but didn't warn you again for Chrome because they'd already warned you about .dmg files?

</comment><comment><USER10> Dunno - I just tried it in Chrome on a Mac, same site and didn't get a warning. Computers eh?

</comment><comment><USER11> I'm running Mojave (10.14.6) and just tried to download Firefox using Chrome 78.0.3904.108 and was not prompted at all.

</comment><comment><USER12> Pretty sure Chrome says that for all .dmg files, not just Firefox.

</comment><comment><USER13> Yes, it is harmful to Google.

</comment><comment><USER14> Isn't this libel to some extent?</comment>


Horcrux Encrypted Messaging - <AUTHOR> https://www.notion.so/Horcrux-Encrypted-Messaging-78af0a3f326244ebb0aedff7c298953d <comment><USER2> A few points:

* The 0day argument (that using multiple apps reduces exposure) is a poor one. If we're talking about 0days that allow message decryption from a MITM, this is true--but if we're talking about RCE with (on mobile OSes) a local sandbox escape (e.g. [https://threatpost.com/whatsapp-zero-day-exploited-in-target...](https://threatpost.com/whatsapp-zero-day-exploited-in-targeted-spyware-attacks/144696/)), then installing more apps _increases_ the attack surface and thus the risk.

* Another argument for multiple services seems to be some implied DOS resistance. But of course exactly the opposite is true: if you split your message and deliver it via multiple channels, any one of those channels can be taken offline and thus thwart message delivery.

* The real argument for multiple services seems to be based on an assumed threat model of an attacker who primarily relies on lawful intercept orders, _not_ on technical capabilities (e.g., a warrant, not cryptanalysis). Adding multiple services may do little or nothing for the latter threat, since many messaging services rely on the same underlying protocols (e.g. the Signal Protocol) or the same crypto primitives. This is important for my next point:

* If the threat model is about lawful intercepts, and you actually trust modern crypto, this entire scheme makes no sense. Just share a public key for a common, well-vetted algorithm. Encrypting messages using an air-gapped device makes sense.

* Further, if we trust crypto, this scheme's sole value is effectively in contact (or public key) discovery: assuming you can't meet face-to-face, the point of this scheme is really to allow multiple services to help you discover a contact's public key (assuming we replace the unnecessary OTP approach with public key exchanges). But many (most?) of these services rely on the telephone system for identity--so there's still a fairly trivial single point of failure, commonly controlled by the government.

* To beat a dead horse: if we don't trust modern crypto, it's likely an adversary can access all components of the message+OTP anyway (even without lawful intercept capabilities), so this scheme adds no value.

Summary:

This proposal would benefit by a more clearly stated threat model. As-is, it's hard to come up with a coherent threat model where this proposal adds value.

<comment><USER3> Hyperbolic claims aside†, I think this is a practical way to dramatically increase the security of OTP key transmission over networked communication. It's not perfect, but it would make any attacker's job harder, right?

E.g. attacker may have no idea where the OTP key is sent, nor on what messaging platform, and would need to crack earlier messages to potentially find out what the communicators were using for all other parts of the horcrux cohort. That's a chicken and egg problem for the attacker. The information on exactly where and what the other horcruxes are could be residing entirely elsewhere in a very encrypted way, or even discussed in person.

[†] I'm interested in the hyperbolic claims about OTP in and of itself bringing 'perfect secrecy' via networked communication. Aren't the mechanisms to transmit OTP keys (i.e. the transport mechanisms over the network) prone to weaker security than the OTP mechanism itself? But again, I think that's what this idea helps mitigate.

<comment><USER2> Right, you're spot on about the OTP. The pad is itself transmitted over the same channel(s) as the message, so there's no value in using an OTP per se. I think the author was just going for a way to split a message in a way that one needs all parts of the split message (or key) to decrypt it.

I'm not sure I buy your argument for the value this may provide, though.

* The question you pose for an attacker--which platform and which device/identity was used to send a message of interest--already exists, in a more general form, for any attacker. Our threat model presumes the attacker has solved it, or else we wouldn't need e2ee to begin with.

* If you're going to discuss something in person, instead of discussing how to use a small number of different channels or identities, just share cryptographic keys!

It's my strong sense that the author is mostly ignorant of encryption itself (hence the misuse of OTP) and instead is trying to solve for the problem of lawful intercept (and hence the digression about supply chain security). This is a somewhat reasonable concern, but I don't think the proposal does much to help with it.

As I noted above, barring assumptions of extremely pervasive full stack compromise (or full compromise of common cryptographic primitives, an air- gapped dedicated device for encrypting messages with preshared keys provides all the security of this scheme, reduces risk (e.g. of 0days), and is far more usable.

<comment><AUTHOR> OTP is not sent over the same channel.

Is there some other way I can explain it better, maybe a specific section on a Threat Model (there's a vulnerabilities section to include things not in the threat model).

<comment><USER2> OTP is sent over _one_ of the two channels (or _m_ of _n_ ). The lint is that the pad has effectively the same security as the message itself.

In terms of explaining, try to describe specific threats (including what the attacker can and cannot do, ideally with a real-world example).

E.g. can your attacker:

* Observe ciphertext? Do they have global network MTIM? (Passive or active?)

* Break e2ee? For example, do they have the ability to derive messages from merely passively observing ciphertext?

* Compel service providers to share any data the provider has?

* Compel providers to serve malicious code to their users?

Etc.

This proposal is missing any formal threat model, so it's hard to evaluate what it's _intended_ to do. I cannot immediately come up with a threat model where this makes sense, unfortunately.

<comment><AUTHOR> >OTP is sent over one of the two channels (or m of n). The lint is that the pad has effectively the same security as the message itself.

Yes! Exactly, that's the brilliant part of this. There is symmetric trust (distrust really) of every channel. We equally distrust all channels a bit, and expect them to be exploitable by different non-overlapping parties (see Venn diagram). In old times you couldn't do this since there weren't so many ways to communicate, and they were all insecure except one very very expensive one.

Nowadays, there are multiple channels people use which are all mostly secure using modern crypto, except for some very specific vulnerabilities and state- sponsored attacks, but usually only from 1 or otherwise very expensive per attack. That's the innovation that Horcruxes exploits! Do you see?

There is a section on Threat Model, also if you just think about it you can imagine the threat models yourself, looking at what it does and the use cases. I've added those explicitly into that section.

<comment><USER4> " _We equally distrust all channels a bit_ "

The problem is you're proposing a scheme that's completely insecure if all channels are being watched by the same entity. The fact you're not employing public key encryption to mitigate this issue is really weird.

"expect them to be exploitable by different non-overlapping parties (see Venn diagram)."

Don't. NSA knew about the Sony hacks because they had hacked the systems of North Korea's cyber army. There's no telling if they're inside e.g. WeChat's servers.

Cryptographic security is on so different level it's hard to emphasize it. Perhaps a comparison to computational effort would suffice:

Let's say a zero-day exploit to compromise one server costs 1,000,000 USD. Let's say brute forcing an 80-bit key also costs 1,000,000 USD. Let's say you're using two servers to deliver the alone unbreakable horcrux halves. It's costing exactly 2,000,000 USD to recover the message

This is the equivalent to brute forcing an 81-bit key. My point is, it's much cheaper to break the channels than it is to break the encryption keys that start from around 128 bits and go up to 256 bits.

" _In old times you couldn 't do this since there weren't so many ways to communicate, and they were all insecure except one very very expensive one._"

In the old times there was no encryption whatsoever in Yahoo Messenger, MSN messenger etc. In the old times there was no E2EE so you only had to hack the servers to get access to massive amounts of user data (this still holds true for some shit services, e.g. Telegram).

" _\--except for some very specific vulnerabilities and state-sponsored attacks_ "

State sponsored attacks are about hacking endpoints, like Besos' WhatsApp. And Horcrux doesn't solve this in any way. Even if your magic wand is an airgapped device. See

[https://ieeexplore.ieee.org/document/7122176](https://ieeexplore.ieee.org/document/7122176)

and

[https://www.computer.org/csdl/magazine/co/2015/07/mco2015070...](https://www.computer.org/csdl/magazine/co/2015/07/mco2015070059/13rRUNvgyZk)

</comment></comment></comment></comment></comment></comment></comment><comment><USER5> > The encryption can be broken in the future if the rival states become > allies, or otherwise become willing to share data with each other.

Witty, sure, but I would not trust it with sensitive data at all if it is relying on political relations ("politics") _only_.

> Many [vulnerabilities] in Whatsapp/Telegram/Signal

Please provide citations for currently known vulnerabilities of each of these, then.

Telegram does not even support "secret chat" (E2EE) on their desktop and web version of the software[1]. No need for vulnerabilities here.

[1] [https://tsf.telegram.org/manuals/e2ee- simple](https://tsf.telegram.org/manuals/e2ee-simple)

<comment><AUTHOR> Horcruxes are just a layer of security. If you want to further encrypt (or do more steganography) on the messages then it is not hard to add that too depending on your threat model and paranoia level.

Horcruxes provide a unique solution to the problem of dragnets and increase costs of hacking your device even for governments.

<comment><USER6> The idea of layering security is very powerful, acknowledged in this "Network Operations Division Cryptographic Requirements" document

[https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%...](https://wikileaks.org/ciav7p1/cms/files/NOD%20Cryptographic%20Requirements%20v1.1%20TOP%20SECRET.pdf)

> Certificate validation must not be performed against any standard SSL root > CAs.

> implement an inner cryptostream within the SSL tunnel transfer

People often state that you should not roll your own crypto. Definitely, you look foolish for making a mistake doing your own thing. However, adding your own layer on top of a standard one seems safe and likely to slow an adversary down considerably. Adding a layer below to encrypt data before the standard algorithm gets it has some risks (e.g. could leak in some complex way like a timing attack) but it also protects against a compromise in the implementation of the standard algorithm.

Adding the Horcrux layer of multiple channels does seem to increase security at the cost of creating a new unvalidated magic wand that then becomes the attack surface - and another significant cost in that it is not user friendly and involves considerable effort per message. There are ways of implementing greater security at high cost, e.g. point-to-point communications off network. The question is if the extra effort confers any benefit. Sometimes just the fact that two parties are communicating is valuable knowledge and this Horcrux mechanism actually makes that easier to detect as it occurs across multiple systems.

<comment><AUTHOR> All good points, agreed with all.

> Sometimes just the fact that two parties are communicating is valuable > knowledge and this Horcrux mechanism actually makes that easier to detect as > it occurs across multiple systems.

Steganography can alleviate that red flag.

</comment></comment></comment></comment><comment><USER7> This lacks a clear threat model and even overstates many problems it claims to resolve (e.g. vulnerabilities in Signal, et al).

I'm not very certain what value this adds to the landscape. Is it possible the developers can elaborate here?

<comment><AUTHOR> I added a section on Threat Models as examples

</comment></comment><comment><USER8> An interesting idea, I was thinking why not use public key encryption instead of transmitting keys in plain text, but it doesn't really make sense to do so. Breaking the public key encryption only requires the plain text or the public key (assuming it can be cracked) so horcrux would not help.

However, using a symmetric algorithm like AES could give you better performance since that would reduce the bandwidth overhead from O(h * n) where n is the size of the message and h is the number of horcruxes to O(n + k * h) where k is the size of the key.

<comment><AUTHOR> Yes a few people suggested that.

Note that I am maintaining ZERO infrastructure here (important! also since it can help prevent DOS!), so it doesn't cost me anything to send these. A lot of these messaging infrastructures are free to users too. So does it really matter that it's O(h * n)? h will always be not that big too, (n as well!) so it's not that much data. It is not much data, and costs me nothing, and costs the user nothing. Does it matter?

I like that OTP has perfect secrecy and is super easy to code and audit the code (NSA hasn't snuck in any weird matrices, no weird goto return bug, buying a bigger quantum computer doesn't break it, etc).

You could also use Horcruxes to set up public key encryption or a key exchange, then do the rest of the communication on a new channel directly using public key encryption.

</comment></comment><comment><USER9> > This encryption is perfect secrecy

Sending your key in plaintext over a separate channel isn't really perfect secrecy but okay... it's interesting, but laden with assumptions.

<comment><USER10> What do you mean plain text? It's scrambled using the OTP then sent. Each sent on a separate channel. The only way to crack is to intercept both. Or if the random generator is weak and can be predicted.

<comment><USER9> > What do you mean plain text?

This: "We will send the ciphertext through Signal and the one-time pad through WeChat."

You're sending the OTP in plaintext. This is the age-old key distribution problem, and that's not magically solved by using a separate channel.

<comment><AUTHOR> I used those words, but if you understand how OTP/XOR works, they're both kind of OTP.

They're both totally random 0's and 1's. Only putting them together (using simple XOR) makes them a message.

The separate channels is important since each is mostly E2EE secure except for the whole government spying problems, but usually not all of them cheaply on each service. We live in unique times now where this wasn't as relevant or possible before.

Does that make sense?

<comment><USER11> No, it doesn't.

People who are anonymous can generally have anonymous conversations. Once anyone becomes interested in those conversations, they are not anonymous and none of their existing strategies are applicable.

State actors have the resources to store messages now and correlate them later. If either is plain text, the other will fall.

</comment></comment></comment></comment></comment><comment><USER3> Just another thought, although IANAL: while it's probably OK to use the word 'horcrux' in casual discussion, for an actual product, even if non-profit, it may be unfeasible to use that word because it's part of the Harry Potter IP.

Maybe I'm totally wrong because it's a different enough industry to be able to use it, but what happens in practice however is another thing. Remember Jo Rowling is a billionaire, hehe. Also, it's a completely unique word that she proudly invented. She said before creating it she checked and Google had zero results on the word.

<comment><AUTHOR> Yea some queer bloggers are going to help me find a better name too since we don't want the association with what JKR is talking about these days

This doesn't help but XORcrux would also work maybe

</comment></comment><comment><USER12> It's a cool idea but I think it's hard to imagine how a user would perform this type of messaging transparently. For example, signal doesn't support bots today or really any kind of unofficial API access so the idea of increasing the number of messengers I need to manually interact with to send a message seems like a big UX burden.

As with all things, the simplest UX will probably win.

Lastly, if you use a single client like a phone for sending/assembling all of your horcruxes, that's probably the place that an adversary would target.

<comment><AUTHOR> Let's be more creative here Josh :)

Maybe not Signal, but there are multiple secure encrypted email clients which DO have programmatic access including ProtonMail, DeltaChat, and others which are under different jurisdictions around the world.

Also you can compile and run your own custom version of the open source Signal Client which does have programmatic access :)

>Lastly, if you use a single client like a phone for sending/assembling all of your horcruxes, that's probably the place that an adversary would target.

That vulnerability is listed and described in the doc. It still has security, just a different threat model, just not as much security as using multiple devices.

Note that under your one Signal app one device, you have no way to prevent this attack at all. Horcruxes now open up new possibilities.

<comment><USER4> From the documentation:

" _Often the 0-days are targeting the most common platforms, so using a lesser used platform increases the attack cost linearly or superlinearly._ "

There's only so many platforms. The exploit would either be directed against the app itself or the OS or some other popular software package like SSH server running on the endpoint.

The threat model of Horcrux doesn't differ from Signal: both are effectively networked TCBs. This will hold unless you explicitly spec it to run on other systems like airgapped, or split TCB configurations.

" _Horcruxes now open up new possibilities._ "

What the world needs is less vague marketing language, and more concrete examples.

<comment><AUTHOR> What is TCB?

> What the world needs is less vague marketing language, and more concrete > examples.

Please chill out with the attacks, this is an idea I'm not selling anything. There's a multi-page doc describing it in detail, not vague at all.

Threat Models enhancement over Signal described in the doc:

## Threat Model

One set of threats this protects agains is any for which people would use Signal for: encrypted security. Also consider the threat in case a Messenger is compelled by the its local government to leak keys on the client (say through an app update) or server by warrant, or there is a rogue employee at Messenger company who compromises.

Often a high security environment will compile its own version of Signal's open source client, however it will be days or weeks old and have published vulnerabilities. Horcruxes would allow the high security user to send 1 horcrux on the custom compiled Signal version, and another horcrux on the public app store version (in addition to others), thus increasing the cost significantly of hacking all horcruxes.

<comment><USER4> " _Please chill out with the attacks_ "

I'm not attacking you, just the concept. The goal is not to hurt you, but to protect others. Please don't take it personally!

" _What is TCB?_ "

[https://en.wikipedia.org/wiki/Trusted_computing_base](https://en.wikipedia.org/wiki/Trusted_computing_base)

" _One set of threats this protects agains is any for which people would use Signal for: encrypted security._ "

Well, yes, confidentiality is the desired property of encrypted messengers.

" _Also consider the threat in case a Messenger is compelled by the its local government to leak keys on the client (say through an app update) or server by warrant_ "

I'm not sure what the EARN IT / LAED bill's status is, but for now what holds is US vs Bernstein that established code as speech, and thus protected with 1st amendment, which includes backdoors (effectively compelled speech, also protected under the 1st). Also, Signal has pledged to move abroad if the bills pass. Given that the clients are reproducible and FOSS, I'm going to take any claim that the US government can just force a die-hard cypherpunk like Moxie to add a backdoor and keep that quiet with all his contacts at the ACLU and thee EFF, with a truck-load of salt.

" _rogue employee at Messenger company who compromises._ "

The git tree is a rather permanent log for who merges a backdoor into the code. Also, there's most likely some form of code review especially wrt security critical code.

" _Often a high security environment will compile its own version of Signal 's open source client_"

Citation needed.

Also, why wouldn't the independently compiled client also update itself automatically via Signal's servers? It's not like the APK version ([https://signal.org/android/apk/](https://signal.org/android/apk/)) doesn't also update itself.

" _Horcruxes would allow the high security user to send 1 horcrux on the custom compiled Signal version, and another horcrux on the public app store version_ "

The thing is, Signal can only be compromised by hacking the endpoint, as can Horcrux. If you're relying on the secrecy of the CT delivery mechanisms, you're essentially attempting security through obscurity that only adds log2(n) bits of security where n is the number of possible delivery paths.

<comment><AUTHOR> I think you're still missing many points of this.

The idea of trust Signal no matter what is funny though.

<comment><USER4> There's other stuff protecting you when it comes to Signal: FOSS code, professional audits, reproducible builds etc.

If you can't trust networked TCB there's not much you can do anyway. Adding one or more networked TCBs that also need to be compromised isn't going to turn into anything magical.

It's about the architecture, and if you need architecture of "no sensitive key/pt material on networked device(s)", you're out of options quite fast. It's either airgaps (shown to be weak as I linked the IEEE etc. articles above), or split TCBs (AFAIK my research on that is the only public work available).

</comment></comment></comment></comment></comment></comment></comment><comment><USER13> There is some magical thinking in this proposal as relates to key creation and transmission — I do not think it's as easy as the author proposes to get enough entropy for a one-time pad from QR codes, for instance. A giant QR code gives only 406 bytes, and the ones phones trade are usually smaller. Also, it is easy to scan a QR code automatically by its nature.

That said, I reinterpret this idea slightly and think it's brilliant — to Shamir split a message between different channels is a really good idea. To split them in such a way that different nation-state actors will each encounter significant expense is pretty brilliant.

Ultimately, (and I think this is acknowledged), for this to be usable you're going to need a device that you don't think is compromised to read and send; In the crypto world, the canonical device would be a formatted flashed older phone that you never turn on data for; it would then use the camera to scan and incorporate the QR codes sent through each channel and recombine them.

If that's the best usability Horcruxes provide, they are going to be used only for ultra-high-value short communication — private keys, passwords, GPS locations of very high value.

TL;DR The proposal provides some improved messaging security but at high usability cost. I think it's _probably_ better than not using it if you use it as an app on your "main" phone, but it doesn't give full benefits in that mode.

<comment><USER4> " _To split them in such a way that different nation-state actors will each encounter significant expense is pretty brilliant._ "

That's where the concerns start. There's no data about which services are compromised by which entities, no effective threat model, no dissection about the expected capabilities of the attackers. No recommendations for through where to pass the shares. It's not at all clear why'd they recommend WeChat that's not E2EE at all. It's also expanding the TCB by encouraging installation of insecure apps (like WeChat). It's also relying on the assumption it's always the case at least one channel isn't compromised, which is really weird, it would be much better to do airgap-to-airgap public key encryption instead, at least on the inside. That way the networked endpoint(s) receiving the shares is not the weak point of the system. Finally, as was mentioned, the app will leak metadata about the communication to every service used to deliver the shares.

" _In the crypto world, the canonical device would be a formatted flashed older phone that you never turn on data for_ "

Well that assumes the Baseband processor does not talk to cell towers. Airgapping a mobile device isn't very easy so a cheap netbook might do better. Or, a more modern phone like Librem with mechanical kill switches for cell/wifi would be much better.

The problem is also, is the QR-code safe, what if you unknowingly scan an exploit that then exfiltrates data off the airgapped device inside the next QR-code containing a share.

It's a nice thought experiment but there's simply not enough benefits to beat the problems, and at most I can see this increase the attacker's cost slightly, instead of automated remote exploitation of single device, they now need to exploit a few devices receiving shares over (possibly E2EE) apps.

</comment></comment><comment><USER14> (Edit: while reading further this went from "overstated claims" to "potentially big security issue", see the edit below.)

It's definitely an interesting idea, but the security claims are rather overstated. If "Horcrux" has a vulnerability, then no, you don't necessarily have to hack each of the transport services to abuse that vulnerability. Depending on what kind of vulnerability it is, you might be able to send someone a message that their client parses and runs your malicious code, or perhaps it leads to plaintext recovery or malleability when you intercept or tamper with only one service.

Another thing to note, somehow missing in the table of (magical) claims where Horcrux comes out on top in every comparison, is that metadata is a problem that you're greatly exacerbating with this. Now not only the USA knows who talks to who, but also Russia and China (in the example given with VK and WeChat). I'd be happy for my chats to run encrypted through Russia since they have very little else on me and distributing who knows what is a good way to prevent someone from knowing everything, but it's still a thing to note.

Edit: And reading a bit more in detail... this seems worrying:

> We will send the ciphertext through Signal and the one-time pad through > WeChat

So if a service assumes that a three-byte message is "yes", they can change that into "no " (note the space) by just xoring against one of the two messages ('ciphertext' or 'one-time pad') right? You don't need to capture both.

The claim "no passwords, encryption keys, and no complicated key management. There is no trust of any complicated public key algorithm, key lengths, or code" makes that there is also no way to verify authenticity of anything. You just have to hope that China, Russia, and the USA all independently decided not to mess with you today; it takes only one, not all three/N.

Proof of concept:

Send (hex) c64d2d through service A and (hex) bf285e through service B. The recipient xors them together and gets (ascii) "yes", the original message.

Now what if service A decides to tamper with it? They xor c64d2d with "yes" and get bf285e. By no coincidence, that's what will be sent through service B. They can xor anything against that, such as "no " (6e6f20), which would result in d1477e. When the recipient receives d1477e from one channel and bf285e from the other, they xor it together and show the message: no.

<comment><AUTHOR> > Proof of Concept Heh, that's funny, the threat model was looking at > observing text, not changing it. I haven't heard about anybody making things > tamper-proof from a government that has got your keys.

Signal, of course if they get your keys by force, can do the same thing, just on a single client. So there isn't any more security.

Finally, if you have 3, 4, 5, horcruxes, then they would still all need to cooperate to get the messages in order to do this perfect XOR (and remember they need to hack through the E2EE on each service too by getting your keys).

<comment><USER14> > Signal, of course if they get your keys by force, can do the same thing, > just on a single client ... So there isn't any more security.

What? Keys "by force"? So if they come to my house and threaten me? I doubt that any security scheme holds up under that, yours nor theirs.

> Finally, if you have 3, 4, 5, horcruxes, then they would still all need to > cooperate to get the messages in order to do this perfect XOR

I won't spend another 30 minutes making another POC but I'm fairly sure that this is not true.

Have you tried it?

If I'm not mistaken: the third, fourth, and fifth OTP are xored together with the first and second, and are therefore the same as xoring messages 2..5 together into one value and xoring that with the first message. The result of {plaintext} xor {any of them} will match the value of {xor the others together}. Therefore any of them can decide to do the attack and they don't even need to know how many other messages/channels/OTPs/horcruxes there are.

<comment><AUTHOR> "by force" I mean force Signal to ship code to the end user to upload the private keys so they can give it to the government, as described in the doc....

Oh I see what you mean about modifying. Good point. That's not in the threat model, I haven't heard of people doing that, but if it is a worry and you want to add it to the threat model, it's not hard to add a hash to the messages that will be a commitment scheme to ensure that you have all horcruxes and they haven't been tampered with. That's pretty easy.

<comment><USER4> " _it 's not hard to add a hash to the messages that will be a commitment scheme to ensure that you have all horcruxes and they haven't been tampered with_"

Oh dear god. No, hashes aren't to provide authenticity and integrity for messages under hostile conditions, look into Message Authentication Codes (effectively __keyed __hashes) like HMAC-SHA256, or use modern hash function (SHA3-256 or BLAKE2) in H(key+message), or since you 're going for information theoretic security, look into unconditionally secure MACs like one-time MAC and Carter-Wegman MAC. Also, make sure to compare the purported tag to the evaluated one with a constant time function. This is so low level I'm not at all confident at your ability to implement this stuff so please take a course in cryptography before implementing anything and if you do, make sure to put a huge banner "This is a hobby project intended to learn about cryptography, do not use it in production". This is to protect you and others.

<comment><AUTHOR> That's why I wrote "commitment scheme" of which there are many and which secure one you use doesn't really matter.

<comment><USER4> " _That 's why I wrote "commitment scheme" of which there are many and which secure one you use doesn't really matter._"

Please see [https://en.wikipedia.org/wiki/Commitment_scheme](https://en.wikipedia.org/wiki/Commitment_scheme)

It's a completely different thing. Authentication isn't about committing to something that's revealed later. Authentication is about detecting any changes in the plaintext content -- that would indicate the new message is from different author.

</comment></comment></comment></comment></comment></comment></comment><comment><USER15> Is this a member of Notion.so staff? How is it possible that you can blog with Notion?

<comment><AUTHOR> Notion free personal version let's you publish links publicly (just not be SEO). It's awesome! Way nicer than google docs.

<comment><USER15> Cool!

</comment></comment></comment><comment><USER10> The problem is the UX and can be cracked if the receiver is lazy and always have both channel close by for convenience

<comment><AUTHOR> That's true. You could end up with bad Opsec and then accidentally download both Signal and Telegram on the same device, reducing (but not eliminating) security. Thanks I'll add this to vulnerabilities.

You can mitigate that with some upfront choices. For example, use a blackberry and blackberry messaging as one device, which wouldn't be available on other devices?

</comment></comment><comment><USER16> Obscurity isn't security, its just administrative overhead + additional points of failure.

</comment><comment><USER17> Meta/side-track: notion is a _horrible_ publishing platform. I can see its use as a wiki/documentation solution (although I disagree with many of the UI choices they make and would never personally choose it) but none of these points actually hold when I'm just _reading_ a published page.

Export it to markdown, and dump it on a github page or something. At least that way we can use space/PgUp etc to navigate.

<comment><AUTHOR> Originally I had it as a Google Doc. That got 0 votes on HN. This is my second attempt. Super easy upgrade to Notion. I agree could be better, but further raising the bar to publishing might mean I never do it :(.

Actually the feedback about not being able to use space / PgDn is good feedback for the Notion team. How do we relay feedback to them? :)

<comment><USER17> FWIW, I don't think the google.com vs notion.so domain was the distinguishing factor here. Whether or not a submission gets votes is a pretty random process in any case.

I think the notion folks should be well aware of the UI issues, since they're long standing. They simply don't care for people that don't navigate with an Apple (TM) touchpad.

<comment><AUTHOR> i'll put it up on my personal blog jperla.com/blog and then re-post it. Seems like this got abruptly banned from the front page for some reason as it hit 50 upvotes...

<comment><USER18> what, not banned, just not trending up....

anyways, don't repost as this one got traction (time of posting is a factor also re: google doc one) and the comment discussion is all here, don't need another version of same thing

</comment></comment></comment></comment></comment><comment><USER19> I know it may sound pedantic to the uninitiated, but the name immediately triggered me / made me uninterested - as it would to any trans person I know - because it's using a name from Harry Potter. Something we have a hard time just 'getting over' or 'ignoring', and certainly shouldn't be asked to.

The author, JK Rowling, is currently on the single biggest hate campaign I've seen a celebrity run against trans rights.

It's negatively affecting the connotations of being associated with the 'Potterverse,' and support for Potter these days is widely considered inconsiderate, especially in the ever growing queer community.

Simply using a name like this was enough to turn me off, and certainly I would not want any friends to have a similarly triggering experience, so I therefore can't recommend it's use, either.

While Potter actually used to be a portal of expression for these types of people, it is now associated with repression and ignorance.

It sucks that any time I see media related / referencing Potter I honestly am immediately disgusted, but this is clearly what Rowling wants. She has had many chances to step down and apologize to her fan base, but she insists on invalidating us.

I grew up with those books, they meant a lot to me, and actually produced a crisis of faith to me with regards to separating art from the artist.

Michael Jackson was, pretty definitely, a child molester. I listened to his music for years after until I finally decided I couldn't do it, as a survivor of sexual assault myself, it makes it difficult to be caught casually listening to him.

The Potter books are good, but there are a lot of other great books out there (and inspiration for names!) that wouldn't immediately turn off any and all potential trans customers like myself.

I will note that it could be _amazingly_ positive PR for you guys if you chose to rename the app for this program, I know I myself would sent it to a few of my queer tech blogging friends.

Unfortunately, to even be a fan of Potter any more is to be a fan in spite of, or choosing to ignore Rowling's continuing, relentless campaign to invalidate us as people, and has drawn tangible battle lines between fan communities.

<comment><AUTHOR> I hear you and I agree I'd rather not be triggering that. I tried asking a few people and trying to come up with a different name and people didn't understand it as easily. Horcruxes give you an idea of what it's doing basically just from the name (you could even imagine a cryptographer inventing this system just from hearing the name it is so obvious).

Do you have an idea for another name for it that will communicate the idea as well? Maybe you can activate your queer tech blogging friends so that we can come up with a new name? (and then I can resubmit under the new name, since Notion will change and kill this link once I change the name).

What else can be split up into pieces and you have to get all of them?

<comment><USER19> If this is a conversation you're willing to have (and kudos for that, and I'm glad you're previously aware of the issue), it's something I'd love to help discuss - I'm a software dev as well, so I understand how the concept of the functionality is well suited for the metaphor - however, I'm _positive_ another solution could be found. :) And, again, it'll of course be great PR and could draw some positive attention to the service. I've made a throwaway email - psyche at theoic dot me - as obviously the nature of HN makes it difficult to communicate here.

I'd love to just offer a little bit of help, brainstorm for a bit, and I think it's fantastic that you're aware of the issue and wanting to take the steps forward. Knowing _is_ half the battle. ;)

I appreciate the response, regardless of anything - I know it might seem like an extreme response without context, but Potter truly has been an extremely hot button issue lately.

<comment><AUTHOR> email sent

<comment><USER19> Oh, fantastic. I'll be sure to get back to you within an hour or two while it's still fresh in our minds. :)</comment></comment></comment></comment></comment>


Interview with Matt Asay of Canonical - <AUTHOR> http://interviews.slashdot.org/story/10/03/02/186206/Matt-Asay-Answers-Your-Questions-About-Ubuntu-and-Canonical <comment><USER2> From March 2010...</comment>


California's Upward-Mobility Machine - <AUTHOR> http://www.nytimes.com/2015/09/17/upshot/californias-university-system-an-upward-mobility-machine.html?_r=0 <comment><USER2> The page outlining the ranking was submitted here: [https://news.ycombinator.com/item?id=10234071](https://news.ycombinator.com/item?id=10234071)</comment>