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Sadly, Crypto 2 seems to be delayed to Oct 15 now.


Awww, dammit. I was looking forward to that. I only checked a couple of weeks ago.


My knowledge of this topic is limited but I believe if you are saying that the majority of crypto libraries have had major bugs, in the sense that they are made trivial to break, that you are overreaching.

On the other hand if you are including minor bugs, that have a low impact on security, then you are surely right but this doesn't mean much. Minor bugs get caught even in audits of the code for nuclear power plants.


jerf started from two propositions, 1) "a sterotype exists" 2) "the study is correct" he argued that these propositions imply the proposition "a stereotype does not exist." This contradicts the starting propositions. If you accept his argument then one of the starting propositions must be false. It could be the first, the second or both. He has not said which he believes to be true or false so your response is groundless.


Yes algorithms courses are a bit of a grab bag. Really, whether you enjoy them just comes down to your interests. I loved learning algorithms because the important ideas can be conveyed without getting bogged down in applications. On top of that a lot of what I learned in CS will be useless in 20 years, but algorithms have lasting value.


If you are really worried about government or government contractors building quantum computers in secret to break RSA in order to read your email you can just encrypt with either NTRU or McElice schemes which have been around for a while and aren't known to be breakable with an efficient quantum computer.

Of course if you are truly paranoid you might believe that the government knows how to break these schemes as well. In that case I have a great deal on bulk orders of carrier pigeons that might interest you


It bothers me that finding someone's location is such a problem since the technology exists to do it. How much would it cost to track a boat by GPS? Search and rescue missions over ocean must cost a fortune. Why don't governments subsidize the cost of GPS tracking?


This is what you are looking for: http://en.wikipedia.org/wiki/Automatic_Identification_System Many of these do not transmit particularly far (especially horizontally). Class B's, like you might expect on a personal ship, only broadcast at two watts.

You have to keep in mind though that for all of our advancements, the ocean is still a fundamentally hostile environment. One rogue wave takes your ship out and by the time that search and rescue people can be in the area any survivors could potentially be hundreds of miles away. They had a satellite phone with them, so I am inclined to think that they also had a AIS transponder, but these sorts of situations are difficult regardless.


AIS is for traffic control mostly. What you are really looking for is an EPIRB http://en.wikipedia.org/wiki/Distress_radiobeacon#EPIRBs_.28...

It is standard equipment on an oceangoing boat.


And they had one, albeit not the type that goes off if submerged.


While GPS works nearly everywhere, there's no simple affordable system to transmit your location.

Oceans are huge, and even sattelite transmitters don't cover everything. Example:

http://www.gpstrackersandmore.com/spot2-gps-tracker

http://www.findmespot.eu/en/index.php?cid=102

Even if something like that worked perfectly, oceans are extremely dangerous. A huge wave can destroy even a large sailboat in seconds.


Apparently it is very hard to prove results in average case complexity theory. We don't even know if computational problems that are hard on average assuming P!=NP exist, let alone actually designing a cryptosystem out of one.


There actually are a few "average-case complete" problems. The field was started with this 1986 paper: http://epubs.siam.org/doi/abs/10.1137/0215020

It's true that we don't seem to know how to build a cryptosystem out of them. Part of it is that a cryptosystem needs something stronger than average-case complete, a property more like every instance being hard (possibly excluding trivially easy instances that can be detected and filtered out).


Average-case complexity is a not a topic I know a lot about, and I can't easily get the paper itself, but what the abstract seems to say is that for some particular NP complete problem, if an efficient average case algorithm exists for that problem then efficient average case algorithms exist for all NP complete problems. There is no mention of showing that such an algorithm does not exist.

My reference is Impagliazzo's 1995 survey paper "A Personal View of Average-Case Complexity" where he lays out five possible worlds based on open problems in complexity theory. He calls the world where P!=NP but all NP problems are easy on average "Heuristica." This is still an open problem as far as I know.

On your second point I can say a bit more. Cryptosystems in general do not need all instances to be hard. With RSA for example, there are all kinds of weird attacks, like the modulus n can easily be factored if phi(n) or phi(phi(n)) are products of small primes. There is no need to filter out these cases because the probability of them occurring is so small. There are cryptosystems where an arbitrary instance of the problem is as hard as the average case. This was a notable selling point for lattice cryptosystems when they were first invented.

In the RSA case the probability of these corner case attacks decreases with the size of the instance. So for current parameters the probability is near zero. However, even if you only had a scheme where the probability didn't diminish with the instance size and there are attacks that you can't check for, you can still securely send messages. Say the probability that your key generation algorithm gives you an instance that is hard is 50% (or any constant). You can securely send messages with arbitrarily small probability of having your message decrypted by using multiple keys and breaking up your message with a secret sharing scheme (Shamir's for example) and encrypting each message share with each of the keys. The attacker, able to only get a constant number of decrypted message shares will not be able to get decrypt your message.


There are two things wrong with this. First, you are assuming that a nonzero fraction of people will sign up for every open-membership community available to them, frequent, and vote in each such community. Realistically most people probably can't do this for more than ten communities. Second, even if there is eventually convergence it may not occur quickly. For example, the universe will eventually reach a state of maximum entropy but it isn't something that any of us need to worry about today.


I postulate that it would be a good place to start.


All electronic devices are subject to search at the U.S. border.

http://www.dhs.gov/sites/default/files/publications/crcl-bor...



Let me be more specific. All that is required is "reasonable suspicion" in order to require access to all the files on your computer, unencrypted. "Reasonable suspicion" is a very weak requirement, as you can see from the document linked to in the techdirt article, and is exactly the same as what is needed for an extended physical search or an extended search of non-electronic property. In other words, there are no special considerations that apply to property just because it is electronic.


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