There is more to computer security than cryptography schemes. And besides, as was said , in the hard-drive encryption example, symmetric ciphers are still useful just by themselves.
Specifically, it is said that a quantum computer gives a quadratic speedup in the kind of searches involved in breaking symmetric ciphers. That means it's enough to double the size of the key in order to account for quantum computing...
If you are going to reply to a post about complexity theory, at least know complexity theory, don't just pretend to.
By "number size", I obviously meant the number of digits, since the input to the problem is the number. What base is used is irrelevant, since it only affects the input size by a constant factor. Constant factors are irrelevant in big O notation.
It has been predicted that quantum computing will make current computer security obsolete, cracking any current cryptography scheme
Wrong. As far as current knowledge goes, a quantum computer is not a big help for cracking symmetric ciphers such as Triple DES or AES. It is a big help for RSA, since it can factor numbers in O(number size) time.
Once, someone suggested building in voice recognition for entering an SMS...My reply was, "why don't you just call them instead."
Because it's usually more expensive. That would be a great idea for a cellphone - voice recognition + voice synthesis + SMS for extremely cheap and slow voice calls.
Well, you should probably start by reading related literature. Understanding the problem is easy, knowing the state of the art in complexity theory is much harder, and, even though I can't say I know it, I do know that this problem seems to be much harder than it would initially seem. Read here, for example:
The practical consequence of this is that any proof which can be modified to account for the existence of these oracles cannot solve the problem. Unfortunately, most known methods and nearly all classical methods can be modified in such a way (we say they are relativizing).
Furthermore, a 1993 result by Alexander Razborov and Steven Rudich showed that, given a certain credible assumption, proofs that are "natural" in a certain sense cannot solve the P = NP problem (see natural proof). This demonstrated that some of the most seemingly-promising methods of the time were also unlikely to succeed. As more theorems of this kind are proved, a potential proof of the theorem has more and more traps to avoid.
This is actually another reason why NP-complete problems are useful: if a polynomial-time algorithm can be demonstrated for an NP-complete problem, this would solve the P = NP problem in a way which is not excluded by the above results.
This makes it scary enough for me. Unless, of course, the hope lies in the last paragraph I pasted, but most scientists don't think that P=NP.
Yes, it would be really funny if it was proved that to get the algorithm for solving NP-complete problems quickly, you had to solve a really huge NP-complete problem first. Sort of a self-encrypted cosmical joke.
Here the hard-core gamers may disagree, but the fact is that most new laptops today have enough programming power to be useful for at least a decade.
I think that could be true, but won't because most new software doesn't use the hardware efficiently. If you give a lousy programmer a doubly faster CPU today, his next program will be twice as inefficient to compensate...
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There is more to computer security than cryptography schemes. And besides, as was said , in the hard-drive encryption example, symmetric ciphers are still useful just by themselves.
That's not true, as far as I've read regarding attacks on symmetric ciphers with quantum computing. See these links:
y mmetric+ciphers+double+size&rls=com.microsoft:en-u s&ie=UTF-8&oe=UTF-8&startIndex=&startPage=1
http://www.google.com/search?q=quantum+computer+s
Specifically, it is said that a quantum computer gives a quadratic speedup in the kind of searches involved in breaking symmetric ciphers. That means it's enough to double the size of the key in order to account for quantum computing...
You have a point there, but that's quite far from saying that "computer security" is rendered obselete by QC.
If you are going to reply to a post about complexity theory, at least know complexity theory, don't just pretend to.
By "number size", I obviously meant the number of digits, since the input to the problem is the number. What base is used is irrelevant, since it only affects the input size by a constant factor. Constant factors are irrelevant in big O notation.
Any other questions?
Wrong. As far as current knowledge goes, a quantum computer is not a big help for cracking symmetric ciphers such as Triple DES or AES. It is a big help for RSA, since it can factor numbers in O(number size) time.
The phone I currently use is much simpler than that!
Hotmail? I had a hotmail account before MS bought Hotmail and it worked fine!
Yes. All I want in a phone is to make/receive calls, SMS's, clock and date and a phone book. I don't buy expensive phones.
Did anyone mention third-party software besides you?
Then you probably still pay for a whole minute. At least you would with my operator.
Correction - I meant "I use a prepaid card as do most of the people in the countries I've lived at".
Which won't work very well if you don't have access to email where you are.
Your "free minutes" theory doesn't work for me, I use a prepaid card in the countries I've lived at.
With the added advantage that you don't have to write down the damn shopping list, it's on your SMS memory already.
Nah, the real question is - "how to convince people that the concept of electronic voting is fundamentally retarded?".
Yes, it would be really funny if it was proved that to get the algorithm for solving NP-complete problems quickly, you had to solve a really huge NP-complete problem first. Sort of a self-encrypted cosmical joke.
Maybe it's because you were targeting windows?
Or you can just move to another country...
Xerox invented the GUI, not Apple...
Especially if the patch caused any problems for the computer...
Malaria is also a very big problem. Only in 2005 did AIDS surpass Malaria in terms of death toll.
See this.