Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!


Forgot your password?
DEAL: For $25 - Add A Second Phone Number To Your Smartphone for life! Use promo code SLASHDOT25. Also, Slashdot's Facebook page has a chat bot now. Message it for stories and more. Check out the new SourceForge HTML5 Internet speed test! ×

Comment Re:I like the idea (Score 1) 292

Perhaps. But it's hard to say. Let me construct a scenario, and tell me how you (or anyone!) would notice:

Some ciphers work on blocks of fixed size, and add padding to reach this length if message is shorter. (example: message must be n*16 bytes, if not, pad message with random bytes at the end, until it is.)

Let's say I've backdored a program implementing such a cipher. The backdoor is this: Instead of padding with random bytes, I do this:

1) Take as much of the secret key as will fit in the padding-space. (if 9 bytes of padding is needed, I take the first 9 bytes of the secret key)

2) I encrypt this (using a algorithm that can encrypt any-length messages) using a second hidden backdoor-key.

3) I swap the last n bytes of the ciphertext with this encrypted partial-key.

Result: Message-size is unchanged. Encryption and Decryption works as specified. n-last characters (the padding) looks like random noise, and is supposed to BE random. How do you notice ? How do you detect that the last n characters is really part of the key, encrypted, and NOT random noise ?

(To make this more fun: I left one big flaw in the scheme there IS a easy way to detect that this shit is going on -- but there's also a way to patch that flaw, I'll explain that in the next message if you find the flaw)

Comment Re:I like the idea (Score 1) 292

That still only works if you trust the hardware and software of that computer. The problem is that if the software you used to encrypt stuff was backdoored, it could leak the key (or fractions thereof) in the ciphertext.

It could do this only sometimes, so no amount of analyzing the ciphertext could convince you that it's honest. Perhaps it only leaks the key if run on a friday the 13th. You simply don't know.

The leaked key, could itself be encrypted so that only the entity planting the backdoor is able to "open" it.

Comment Re: I like the idea (Score 1) 292

AES256 is entirely public. Furthermore, that's an *algorithm* not a piece of software -- the algorithm has been *implemented* hundreds of times, by hundreds of independent organizations, some implementations are open source, some are closed.

Furthermore, AES256 says precicely *nothing* about how to create a key, what it DOES say is how, given plaintext and key, you create ciphertext, and how, given ciphertext and key, you create plaintext.

Your claim that government could "have their own key" is thus nonsensical -- you can, if you like, create your aes256-keys by tossing a coin.

Comment Re:Poor people are poor because they're lazy (Score 1) 459

Precicely, and statistically plain dumb LUCK is the biggest of those factors. 95% of all Norwegians are wealthier than 95% of all people born in Ghana, yet where you're born is just luck.

The odds of staying in the top quintile if that's where your parents are, is something like 85% (in USA), the odds of climbing to the top quintile if your parents are in the bottom one, are about 11%. In other words, 8 times as good odds if your parents are already wealthy.

That's not to say impossible: 11% still does mean some people make it. But it says it's damn hard, and probably -also- requires luck (in addition to the hard work).

I'm fairly wealthy, me and my wife pull about $200k/year, and sure we've worked for it, but at the same time a LOT of it is just luck: Born in Norway and Germany. Educated parents. Good health. Quick learners. All of these things helped us enormously, yet we have them just because we lucked out in the lottery of life.

If we worked equally hard, but where born in a slum in Nairobi, odds are we'd be living on 2-3 magnitudes less. So while hard work matters, it's pretty arrogant to go around talking as if hard work is the ONLY thing that matters.

Comment Re:One more reason that such systems make no sense (Score 1) 308

Yes. And if Wikipedia didn't get their sources messed up, then between 15% and 30% of the students would not have qualified, if not for their lineage. Meanwhile 75% of americans oppose the practice, which makes perfect sense to me. The American mythical dream is about working hard to achieve your dream - not having positions and educations handed down to people based on who their PARENTS happen to be.

Comment Re:One more reason that such systems make no sense (Score 1) 308

That's an entirely different objections. Are grades actually particularly good at measuring a persons skills in a subject ? The answer, obviously, is "it depends".

It depends on the subject at hand. It depends on what skills you're interested in. And it depends on how the grades are set. All of these vary considerably.

Comment Re:One more reason that such systems make no sense (Score 4, Insightful) 308

You're just coming from different viewpoints. Universities in Germany are overwhelmingly financed by the state. As such, it's reasonable to ask that they admit students according to a objective, measurable standard as opposed to "whomever they like".

The latter would open the door wide for corruption, it has to be tempting for a private university to admit the children of well-known rich people, for example, both for the PR, and for the potential funding. That's incompatible with a meritocracy.

A anonymously graded entry-exam would be fine. But in my experience, the admission-process to many private universities is not really anonymous, and it seems to me the scope for corruption and basically choosing the richest kid rather than the best-qualified one, is high. (plenty of mediocre sports-stars seems to get in no problem, for example)

That's fine if you see university as a private institution that exists to do whatever it wants to do, including maximize profit. It's more of a problem if your univiersities are publicly funded and exist in order to educate students, prioritizing the best-qualified ones.

Comment Re:One more reason that such systems make no sense (Score 4, Informative) 308

Agreed. It's similar in Norway, but with the caveat that certain studies weigh the different grades differently.

Most studies just rank students based on average grades, with a bonus for those who've taken more than the required minimum of advanced courses. But a few educations prioritize certain grades higher.

For example, if you apply to become a engineer, they'll consider your grades in math and physics more important than your grades in history and gymnastics.

But they still all computer your score from the exist-exams in secondary school, so there's no entry-exams required.

Comment Re:One more reason that such systems make no sense (Score 1) 308

Indeed. Why have grades in secondary school at all ? There's basically two points to it. One is to give the students feedback on their performance. The other is to make it possible to (roughly!) sort students based on skills for higher education.

If the grades can't be used for the second purpose, you might aswell drop them entirely, and instead just give the student a summary of his weak and strong sides.

Comment Re:heh (Score 1) 176

That's the thing though, I HIGHLY doubt they've got 60% of the corporate mobile email phone market. Unless you define that market in a so contrived way that most people who have a corporate-bought phone that's primarily used for reading email on the go, are not included.

Not a single one of the 10 biggest corporations where I'm at even offers blackberry as an option. They've all either standardised on Iphones or some Android-model, or they give employees a choice between 2-3 models, none of which are made by RIM.

Comment Re:Freedom to travel (Score 2) 1233

Absolutely. By going away from home, you do not only learn new stuff about the place you're going, you also learn new stuff about your home. A lot of things just aren't VISIBLE if they've been that way every day of your life, you just don't notice, and tend not to consider that alternatives exist.

I learnt a whole lot about my home-country (Norway) while living abroad for 4 years. Things that are hard to notice, when one country is all you *really* know. And no, watching movies or reading books or whatever is not at all the same as actually changing your location.

Comment Re:Dragon Zakura (Score 1) 91

Of course ! The simpler a sentence is, and the smaller a vocabulary you use, the more easy it is to understand.

So if the assignment is: "Write a sentence that is as easy to understand as possible", then something like "I am a boy" should score top grades. It's among the simplest sentences you can write, and it uses only words that tend to be taught in the first couple weeks of english-class.

If you're trying to set a grade for how much english a person has learnt after several years of schooling, then not so much. Then they should actually demonstrate that they understand and can use both a larger vocabulary, and more grammar and syntax. (on a high level, you'd also want to get idioms and nuances right)

Comment Re:Dragon Zakura (Score 5, Insightful) 91

That I've experienced to. It's a *really* stupid way to grade someones language-skills, but it's an easy way to do it, just count the mistakes, so it's basically about caring more about ease of grading than whether grades are meaningful or not.

"My name is Eivind. I am a boy. I come from Norway. Norway is in Europe. Norway is cold." should *never* score higher than:

"I'm called Eivind and come from Norway, it's a coldish place over in Europe, thoug not as cold as some folks assume."

Yeah, the latter has more mistakes. But despite this it demonstrates far higher skills in english. Failing slightly at constructing a complicated sentence should be preferable to constructing a entry-level sentence perfectly.

Slashdot Top Deals

In the realm of scientific observation, luck is granted only to those who are prepared. - Louis Pasteur