Wow! Does this say that as long as key generation, key distribution, and message authentication are trivial, unbreakable cryptography is a cinch? What a shock, here I thought that all those billions of dollars of research and thousands upon thousands of man-hours devoted to the development of secure communications throughout the last three-thousand years meant that this is a difficult problem. Had all those people simply read this article, we wouldn't have had any sort of issue whatsoever...
Not only are the three problems I mentioned above the most serious open issues in cryptography, but the actual encryption of information might be the least difficult. As long as they are implemented correctly, and no one has some quantum or otherwise impossibly powerful computer lying around someplace that no one knows about (or has solved the Riemann Conjecture), then RSA, El Gamal, AES (w/ proper mode), Blowfish (ditto), and numerous others are unbreakable as well. In fact, with the lack of restrictions the author includes for what constitutes "unbreakable" cryptography, a one-time pad will also work just as well.
And yes, I do realize he gives mention to this at the bottom of the article, but it's still hilarious to title this "unbreakable" cryptography.
I agree that this is a really poor article, but the point underneath is that the OTP really is provably unbreakable given infinite resources. That can't be said of any of the others you mention.
I think your level of scorn is justified, but the target is misplaced, and your tone is unconstructive.
I'll agree I could be a little less demeaning. The point is though that cryptography more then anything else is about its practicality, and so by ignoring the difficult parts of it you render any statement you make pointless. Also, although you are correct about noting that under infinite resources RSA et al is breakable, again, practicality. If it takes longer then the previous amount of time elapsed in the universe to break (assuming proper implementation etc.) then it is, for all intents and purposes, unbreakable.
Do you think that in an article aimed at students that's the right place to start? Side-channel attacks, timing attacks, differential analysis, weaknesses in key exchange, why padding is necessary, biases in pseudo-random number generation, etc, etc, etc ...
Or is it better to start with what crypto is, with key generation, encryption, decryption, then move on into the first level of complexity?
For what it's worth, practical secure cryptosystems only exist under a number of assumptions that, thus far, have no proof. Commonly used public-key systems are in an even more precarious position: even if P!=NP, the RSA and discrete logarithm problems may still be computationally feasible (and thus RSA, Diffie-Hellman, and ElGamal would be insecure). Cryptography based on NP-hard problems is possible (e.g. Atjai's lattice system), but these remain research topics and have seen little real-world use.
The point is this: there is a lot we do not know about cryptography.
XRDS Crossroads is a magazine blog for students, the article presents an actual topic explained for those interested, I think it targets an important part of Hacker News demography and it makes an excellent job in encouraging students to go ahead and develop their own crytographic solution, so I don't know what are you so angry about the article
I'm a student myself. Funny enough, some of us are actually intelligent and can handle complexity. To me, this is the equivalent of teaching military science by telling someone how to shoot a gun. Instead of trying to introduce someone into the field by showing them what questions the field is actually trying solve, you're introducing them into the field by showing them the small subset which those who have no interest in it assume constitutes the entirety of it.
How many mathematicians do you thing have read an article on cryptography, gotten really interested in it, and then realized the most important open question in it revolves around the computer equivalent of spotting a fake ID?
The article explains an implementation of a Vernam Cipher, it's not intended to solve the most important questions in cryptography.
I don't understand how "introduce someone into the field by showing them what questions the field is actually trying solve" could do any good, it's like saying that the first subject in Physics 101 should be the unified field theory instead of Newtonian physics.
Hilarious. This is what happens when you have compulsory military service as a nation which (although constantly under threat) rarely if ever actually sees combat. I can't decide whether it's a better or worse waste of time then the Air Force's professional StarCraft team, but either way, bravo.
PG County is Maryland, not DC. It's the county that wraps around the eastern side of the District, and includes the University of Maryland. The rules of the District don't apply to what they're trying to do. I think the author mentioned them (and those of Montgomery County, PG's far wealthier and higher performing neighbor) to show that the idea wouldn't be possible in those school districts.
Notably, PG County has an awfully run government that presides over a relatively low-income population generally composed of Latino immigrants and African-Americans pushed out of the District itself by rising home prices. I've seen a picture before of the average income levels in the counties surrounding DC. Montgomery, Arlington, Fairfax, and Loudoun counties are all top 10 in the nation. PG sticks out like a sore thumb. Adding to that, they have by far the most racist police force you'll find. A friend of mine has been pulled over and searched multiple times there solely because he is a young black driving a car that doesn't look like it got pulled off the scrap heap. The last thing that county needs is something that stifles the abilities of its younger residents to try and create something new and interesting for their local community and at-large.
edit: okay, I suppose PG county is lower income than Montgomery, Arlington, Fairfax, and Loudoun counties, but the population is certainly not "low income" even for a high-cost-of-living region.
Compare that to other DC-area counties, though. Per the Washington Post [1], Fairfax, Loudoun, and Arlington all have median household incomes over $100,000. Montgomery sits at almost $93,000. So in comparison, $71,000 per year is low.
PG County has wide variance in income. Further out in the county there are fairly well-off people. But there is a dense population of urban poor near the DC border.
I used to live in Greenbelt, in the heart of PG County, and my 2-bedroom-and-den semi-crappy apartment cost $1750 nearly 7 years ago. And Greenbelt is a DUMP. An expensive, expensive dump.
Since the apartments were all full — and not 6 people to a unit, either… -- there's only one conclusion… PG County is a lot wealthier than you think. It's not all in Bowie and "the north."
Looking at it through the economic lens that the author does, I think what he fails to recognize is the payoffs. War has immediate and substantial payoffs. Whether that is material gain, new energy or food sources, pillage, prestige, etc., or moral gain, in the destruction of a regime that commits heinous acts, war has benefits which can be easily seen in the short term, and so it is easier for the governors and governed of a state which chooses to undertake war to make that decision.
Space exploration is significantly more long-term. You're spending billions of dollars (not just lives) for what in the short-term does not seem like much benefit. Although landing on the moon and other such projects are incredible achievements, and although the development of the technologies that have allowed such achievements has dramatically impacted daily life, it's much harder to make clear to people the benefits of exploration in both a human or a economic cost.
If the benefit is defeating Nazi Germany, or Assad's Syria, or Osama Bin Laden, we're able to accept the costs. If the benefit is Tupperware, GPS, and some cool pictures of the lunar surface, then we will most likely not (not that I agree with that, it's just how most people see it).
Frankly though, people around here are generally as reasonable as you'll find out on the interwebs. Sure you'll have people come in and stir things up, but generally I get the sense that the majority of comments and their authors are attacking the question at hand as opposed to the person behind it, and are doing so in a respectful way. The internet as currently constructed will never be perfect in that regard because of the lack of accountability, but Hacker News in general seems to move against the general stream and have some sense of decency, the way that say, early EBay is often described as having.
Religion was created to answer three questions. Why are we here? How are we here? How should we carry ourselves? Its secular cousin philosophy was designed to answer the bookending two.
Empirical science answers the middle question, but it leaves the other two untouched. I'm personally a nihilist, but even if you do not believe we are here due to some divine plan or goal, it is certainly possible to rationalize (and not in a negative sense) a purpose for humanity, such as the pursuit of happiness. As for the latter, although most discussions of the role of religion in general society tend to be negative, the Crusades, Islamic, Christian, and Jewish Extremism, pedophile clergy, etc., to name a few (Western) examples, that religion is the fundamental basis for our morality is lost in the shuffle. Sure the edges can get quite frayed, especially when religions bump into each other, but the basic framework of the way we live was codified and enforced by religion, and without it humanity would have had and would have a much rougher existence. Philosophy has attempted to replace it as a secular approach, but they really are doing one and the same.
So the answer is no. Physics has (thankfully, in my book) replaced one of religion and philosophy's three founding bases, but the other two remained untouched. And now you can say you've come across a nihilistic atheist who loves organized religion...
Knuth's up-arrow notation and the Ackermann function are both designed to make very large numbers easy to notate, but unfortunately I don't know how difficult it would be to write a program to find an expression for any number in one or the other (I'm sure there are plenty of others on HN who can). Might still be worth looking into however.
In principle, not every number can be directly expressed as the result of a nontrivial Ackermann function or Knuth operator (just as not every number is a square or a cube) - although there is a section in the Knuth page you linked on how to represent any nonnegative integer as a series of Knuth-type operations.
I would imagine, though, that to represent an arbitrary integer between 0 and n still needs ceil(log_2(n+1)) bits - since you have to distinguish between n+1 choices, whichever notation you use.
As a former bicycle mechanic and salesman, and someone who is still very tuned into the industry, I'd give this a zero percent chance of actually being successful.
There are three big issues with this design. First of all, you're going to be looking at a seriously increased Q factor trying to fit three different speeds into that gearbox (as opposed to Truvativ's two). The Q factor is the amount of distance between your feet. If you lie down on your back and make a pedaling motion, the natural positioning of your feet is one banana apart. Bikes, to have sufficient stiffness in the bottom bracket region, space your feet two banana's apart or more. Graeme Obree (https://en.wikipedia.org/wiki/Graeme_Obree) figured that out, and when he designed Old Faithful he added a very narrow Q factor, which was a big piece of his success. A huge benefit of carbon fiber is its ability to add stiffness in the BB area by overbuilding without increasing Q factor (or weight all that much), hence the BB30 standard. Truvativ's two-speed front crank is already very widely spaced, and trying to fit more in is going to cause problems. Remember, to balance out the pedal stroke, you have to compensate on the left pedal (I see this is designed to work with existing tech, but it'll feel strange unless you get a longer left pedal spindle), so every increase in distance on the right side is doubled.
Secondly, no part on the bike gets worn out quite like bottom brackets (not including "wear" parts like chains, cassettes/freewheels, tires, etc.). Powerful riders (and not necessarily racers, I know plenty of everyday commuters who fit this bill) tear BB's to shreds. I am a racer, but I'm also a lightly built climber, and I tear through them pretty regularly. Putting a gear box in the BB shell is going to subject it to a hell of a lot of torque, and it'll be difficult for it to stay dialed in and functional with the power output of many riders. The extra mass could also make it uncomfortable to stand up and power out of the saddle. Trek, Pinarello, and a few other companies already reinforce the non-drive side of some of their bikes to even out the extra weight from the chainrings and front derailleur. All the extra mass from a gear box will expound this.
And lastly, internally geared systems are a bitch to maintain, and it's one of the reasons why you will be hard pressed to find a shop which will overhaul your vintage three-speed hub. The newer internally geared systems (like Shimano Alfine and Nexus) are a lot easier to work on, but Shimano spent decades perfecting that stuff. This system is not going to be easy to work on to start, and good shop owners don't sell products their mechanics can't fix easily. It's just not a good proposition.
All in all, a cool idea, but to me far too many issues for it to ever be accepted. As that bikeradar article puts it, no need to reinvent the wheel. Internal hubs and derailleurs (the latter especially) get the job done quite well.
Came here to say this. Internally-geared rear hubs are great for certain mountain bikes, where derailleurs just won't work because there is too much mud. But for everyone else, a well-adjusted derailleur system will be fine. (Yes, you have to pedal forward to change gears. If you're stopped at a light, press the front brake and move the pedals forward. Or remember to downshift as you're braking.)
I've thrown a chain twice in recent memory: once when I was climbing on a chain where I disregarded the rule against breaking the chain without replacing the pin with a master pin (that you break off after driving in), and once when I was trying a new kind of lube on the chain (that worked more like glue than lube). A well-maintained derailleur system is very light and very efficient, and with a bit of practice, easy to use.
Mud always comes up in these discussions but isn't a real problem. You can get mud, water, sand, branches, snow, grass, gravel or entire bushes into your gears and hardly notice it. Sometimes it feels like the whole forest just wants to go into your gears but in some magical way it always falls out again. The more i think about it the more amazing i think it is, the amount of punishment the powertrain takes is quite remarkable and even though the components are so small and precise they don't take much damage.
The only real problem with derailleurs in the forest is when they get hit by a rock, a think branch or the ground. Anything else that doesn't actually bend the derailleur is a non issue. In very very rare occasions something might jam the chain but no changes in the gear are going to fix that. And of course the mud will slowly wear and tear things down by grinding but that's not an issue of the actual gear but more of the cogs and chain.
My reading of the article suggests that it's targeting more casual riders that bop around town, but maybe live in a hilly place, haul kids, etc, and could use some extra gearing.
All your criticisms may be true, but seem to be more about the needs of "enthusiast" / "serious" riders (a category which includes many bike commuters in the U.S., but not so much in other countries).
So despite the issues you mention, there may very well be a place for this tech—and the "non-serious" market is much larger (especially outside the U.S.)...
The cost of this system worries me. The "casual rider" around the world rides very inexpensive bikes. For instance, it's rare to see someone in Japan commute with a bike that's over $150. Low end Shimano components are pretty inexpensive due to their massive volumes. I'm concerned of the possibility that this product is being developed without having rigorously tested for product market fit.
> It's rare to see someone in Japan commute with a bike that's over $150.
Lots of people have cheap bikes, but there's also a big "mid-market" (~$500) for Japanese casual bikes.
I think a robust and trouble-free multi-gear front could be a great alternative for recently popular electric bikes (e.g. on those small-wheel bikes with kid seats)... even if it adds weight and cost, it's surely much less weight and cost (and hassle) than an electric motor and battery...
In france there are pools of bikes to rent in big cities. There are many pools in many places so that you cant pick a bike in one place and leave it at another. These bikes could benefit from such gear system. It has to be extreamly robust to common usage with user not carring about the bike or hardly now how to bike. The bikes are cheap and I think the first half hour is free. Howerver it is a profitable business. So there might be use cases where this product could be a good fit. Its weight seems however to be a bit excessive. Its called vélib.
OK, but you don't actually know the Q-factor of this design, nor how durable it actually is. You're guessing based on not a lot of information.
Although I am also skeptical of new mechanical designs on something as evolved as bicycles, it seems like a good idea and one worth pursuing. Why declare it a failure before the first review!
You can't tell me one and even larger one of these isn't going to cause some Q factor issues. This (the Truvativ) is designed for gravity riders though, where pure pedaling efficiency and fluidity is not at value. Same goes for durability not being as much of an issue. This needs to take rock blows, not miles of wear. I read this product as for commuters and people who put in a lot of miles around town:
And yes, the durability is entirely speculative, but, especially coming from a new company (as opposed to HammerSchmidt, which was 100 or so years old when SRAM, of which Truvativ is a brand bought them), I'd have serious doubts they'll put a top quality product out at the start.
Why do I have a feeling that for the majority of CS students, Shakespeare would be a less intuitive language then Brainfuck?
Some more programming and CS errata for those interested here, a collection of esoteric languages, algorithms, and an operating system: http://www.dangermouse.net/esoteric/
Piet is actually quite beautiful, and just about all of those are quite humorous.
Quite true, but what your post doesn't do enough to recognize is how much this type of thinking has pervaded our culture, and the damage it is doing. The current generation of up-and-coming workers (25 or so and below) have been taught their entire lives that they were special, they were smart, and interesting, and likeable, and that the only thing that was standing in their way was going out and trying. If they did, they'd prevail...regardless of whether they actually had the talent, not to mention the work ethic to put in the hours of sweat and toil to develop that talent into actual skills and learn to put them to good use. I'm a college student now, and the level of assumption about what the world is going to do for us in the future, not us for it, it for us, and the amount of entitlement is absolutely ridiculous. It would be bad enough if these people thought willpower would be enough. They don't even think they need that.
I worked for years in high school as a salesman at my local bike shop, and for a while as well at a television production company, and I've seen multiple people my age come and go from those jobs because they couldn't learn to alter their perspective on how things should work (to no-experience them) to fit with the way things do work.
Not only are the three problems I mentioned above the most serious open issues in cryptography, but the actual encryption of information might be the least difficult. As long as they are implemented correctly, and no one has some quantum or otherwise impossibly powerful computer lying around someplace that no one knows about (or has solved the Riemann Conjecture), then RSA, El Gamal, AES (w/ proper mode), Blowfish (ditto), and numerous others are unbreakable as well. In fact, with the lack of restrictions the author includes for what constitutes "unbreakable" cryptography, a one-time pad will also work just as well.
And yes, I do realize he gives mention to this at the bottom of the article, but it's still hilarious to title this "unbreakable" cryptography.