Quantum cryptography

Interesting reports in the news recently about using optical fibres to produce a system that is 'uncrackable'. A reaonable summary can be found here - quantum , and no doubt elsewhere as well.
Probably be a few years before it is commercially viable, but from a scientific point of view it would seem to have a lot of merit. In many ways a bit like Heisenburg's uncertainy principle - which basically means that, for a single particle, the better you know its position the worse you know its velocity - or vice-versa.

what if you forgot the password to your key?

Must remember to take up a course in typing soon ;) Edited my post so that the link is correct. Like all encryption systems it won't work if you don't know what your key is - but in many ways that is the point - without the key you can't read it. At a software level this could use something like PGP, or something more sophisticated.

Are you ppl here dealing with the idea of quantum compus?

Well some1 said it could be uncrackable?

Why not use quantum computers to crack the passwd key generated by a quantum compu? Even if it was so complicated as a double helix proteïn string it probably can be cracked by some very fast machine. In the process of time every key or hash can be found and translated into plain text, it's just a matter of time. Perhaps a vvvvvveeeeerrrrrrryyyyyyy long time but in theory it's possible. So uncrackable? No way

Quantum cryptography is not unbreakable. Nothing is. It is just that we do not have the feasible technology to do it yet. Simon Singh's The Code Book has an excellent chapter on Quantum Cyrptography that I found I actually had a clue from. (If you are interested in the history of cryptography, this is a book I'd highly recommend).

Scientific American has also has a small article on it:

http://www.sciam.com/news/122200/2.html

Now, one of the biggest issues is the abilities of our present OSes and hardware to be able to handle this stuff at an efficient and cost-effective manner. I'd humbly suggest that not even by military standards do they have the bucks to do it. It will be a few years before this is viable and proven to work in an environment of work or something like that.

I absolutely love this stuff. Now ask me how good I am at math? =D

Quote:

---

I absolutely love this stuff. Now ask me how good I am at math? =D

---

How good are you at math? ; )

I remember reading something that said DES was uncrackable. Then computers got faster. Then that phone encryption by the NSA was supposed to be uncrakable(can't remember the name), but they finally released the source code. That didn't last long. So now something else is uncrackable, but that is only till someone cracks it.

Simon Singh's The Code Book is a great book like MsMittens said. I am reading it right now. There is also a book called CODE, if you are interested in how computers and encryption work and are related. Can't remember who wrote it, but it was by Microsoft Press, so it wasn't the best book.

MsMittens, I agree with rogue, how good are you at math?

I think the point that they were trying to make was that this makes physical interception of the message all but impossible. Well it is impossible, unless someone is keeping quiet about recent developments in quantum theory. If you try to pysically intercept the message then you alter the information that the other end receives - which is not true of any other method used today. All this is completely irrelevant if you send the data via other computers (e.g. ISPs), as the ISP can take a copy of the message.

And as has been pointed out, the most important thing is how you do the encryption, and any other precautions you take. Really depends on how you would implement this type of technology.

Current cryptograhy tecniques are 'impossible' to crack, it's just a question of using a long enough key.

I heard that to crack a 4000-something length key for the RSA-encrytpion algorithm, you would need all excisting computer power in the world. And it would take the rest of the universe' liftetime to do so. And even then, you couldn't be sure of cracking it, but maybe...

But of course there is only a question of computer power, if the computers are powerful enough, it's no big deal really.... In 1997 a 128 bit RSA was cracked by a program which united lots of pc's around the world. Sort of like the SETI screen-saver. And that too, was supposed to be 'unbreakable'.

I would agree with most of the people in this post. It isn't a question: is it unbreakable? but it's really a question of: how long will it take to crack?
As history tells us that nothing is unbreakable, when things get tougher, other things get faster. And vice versa. We're all in an race through a technological black hole. Looks like it'll never end... or will it?
:confused:

and while we wait, is there anything stronger than 128bit comming in the near future? (6 months)

I absolutely suck at math. I think I actually failed grade 11 math (or dropped out before I did). Anyways, The Code Book resulted in me getting more interested in math and not as afraid. If someone had told me that math could help me with cryptography and decoding, I would have stuck it out.

I now have a greater interest in math as I've recently picked up Singh's other book Fermat's Enigma. =)

A quote to live by, in dealing with computers and how far we've come as far as cryptography/uses/etc...someone stated it but I don't remember the source:

I can see the use for up to 5 computers in the world...

Now that's not entirely correct (memory going stale here) but that was back in 195[0-9]. That's like Albert Tanenbaum telling Linus that his "writing of another OS for the i286 earns him his second F for the semester". Or the HS basketball coach telling Michael Jordan that he wasn't good enough to play on the team.

It's just a matter of time. I'm sure the people that wrote the DVD encoding didn't think that 7 lines of code could break it. Everything's "unbreakable" at the beginning. Such is the way of Open Source when you can start hax0r1ng it right away to reverse-engineer it. That's probably the only downside I see to Open Source material.

I'm not criticizing anyone, but it is my strong opinion that no system is completely 'uncrackable'. I believe that within time EVERYTHING can be broken into, reverse engineered, etc. I know that many others feel this way about 'uncrackable' systems.

Agree in principle that nothing is uncrackable, which is why I put 'uncrackable' in quotes :) But if you want to be pedantic there is one exception to this - the so called 'one time pad' which has been used by secret agents since at least the beginning of this centuary. The algorithm used to encrypt/decrypt is very simple, just using a single key, and can be done with pencil and paper (not much else available in 1900!). As long as the key is random then this is completely uncrackable - both parties use the key only once, and then physically destroy it (the key).
I think that is the sort of approach being proposed for quantum based computers talking to each other over a fibre optic link.

This is certainly an awesome development! As Darkes said, the true value of quantum cryptography is not just the fact that there will real random numbers, not the pseudo-random number currently used, or that it might be impossible to "crack," but the value is in the fact that it is impossible to intercept quantumly encrypted data (light in this case). The idea behind this, is that once someone "looks" at the data, the light goes out of superposition (an infinite number of possible "spins") and is forced into a certain state, which won't be what it is supposed to be, and obviously the receiving end of the communication will be able to recogize this.

It is difficult to speculate on the ability to "crack" such encryption techniques because we barely have a grasp on how these superpositions work, and how we can get them to work for us, let alone using other elements of quantum mechanics to "crack" the encryption. As I like to say, the science comes first, then the engineering builds from what the science learns. At this point, science has just begun to learn enough to understand general concepts of quantum mechanics, so it would be presumptious to say it can or can't be cracked until everything is learned about quantum mechanics...and by the way things are going (especially with what looks like some serious changes in theory on the horizon by the solid-state physicists) we won't know the correct answers for quite a while...

If anyone wants to discuss quantum cryptography, or any subject matter of quantum mechanics related to computing, please let me know...I love discussing this stuff...

-Wizeman

Wizeman said:

Quote:

---

If anyone wants to discuss quantum cryptography, or any subject matter of quantum mechanics related to computing, please let me know...I love discussing this stuff...

---

I, for one, would be very interested in this discussion. Now mind you, I'm not a mathematician (nor am I a great speller) but I do like learning about this kind of stuff.

Teach, oh Jedi Master, teach! =)

Well, I'm far from a master at this stuff. I've just read a couple of books and taken some classes involving quantum mechanics. I'm also not a mathematician, and most of the mathematics just back up the theories concerning probability waves and tunneling. Either way, I've been really very interested in this stuff since my senior year in high school, and the applications of quantum mechanics are just enormous. Not only are we just talking about computers that can compute multiple things at one time using (no I'm not talking about multiple processor stuff, but calculating all possible solutions at one time) superpositions, we are also talking about cryptography that could be uncrackable (for good or bad) and some even believe that quantum computing is the only way that we can truly make artificial intelligence.

Anyway, let me know of your interests, so I can speak in more detail about them, or just throw out some theories for discusion.

-Wizeman