Quantum computers

[SATtva]

The cryptography with open key will simply be useless with appearance of quantum computers.

Not quite so. There are public key crypto schemes (error correction codes-based McEliece cryptosystem for example) which are resistant to QC algorithms, but not used at the moment due to exceedingly large keys or other factors.

However, there is quantum cryptography. ... It provides absolutely secure secret key distribution which is later used to encode a message.

...with classic crypto algorithms. The real problem with so called quantum crypto (which actually is quantum key distribution) is that it requires dedicated physical end-to-end channels. So QKD is as much absolutely theoretically secure as absolutely useless for practical purposes.

I don't say it isn't worth to research that field (in fact i have a couple of friends with PhD in quantum physics who work on quantum channels and QKD, and it's quite fascinating to listen to them), but all the hype around this topic created by commercial vendors is sometimes very frustrating.

[Vutshi]

Not quite so. There are public key crypto schemes (error correction codes-based McEliece cryptosystem for example) which are resistant to QC algorithms, but not used at the moment due to exceedingly large keys or other factors.

I'm not familiar with the algorithm but I bet it is possible to crack. Maybe some other quantum algorithm will do the work. If it would be mathematically proven to be absolutely secure against any attack then it would be a huge thing, everyone would know about it.

...with classic crypto algorithms.

This simple classical algorithm (just add a random numbers to your message) is actually absolutely impossible to decipher. The only problem is that you can't use it. It requires first to share the secret key and this is an insecure procedure. This is where one needs QKD.

The real problem with so called quantum crypto (which actually is quantum key distribution) is that it requires dedicated physical end-to-end channels. So QKD is as much absolutely theoretically secure as absolutely useless for practical purposes.

This is not the problem of quantum crypto. This is life. This is the only way of having secure communications when the public key crypto doesn't work due to QC. That is why cryptography will be very different from what it is being now.

[Carbonflux]

Again back to Penrose, the mind itself is the most advanced QC. Maybe someday we will be able to leverage entanglement for secure communications but even then the weak link will always be the human mind, if two people are involved it will always be possible to break encryption, the dirty secret the NSA keeps and others like them is that there is another form of entanglement that will never allow anything to be kept secret so long as a human mind is aware of it, so long as we ignore this there will never be perfect security.

I suspect even a 1000 years from now we will still be stuck with the fact that the human mind is the safe we need to crack, not maths.

Always the most successful intelligence operations involve hacking the people, not the computers.

"Three people can keep a secret if two of them are dead..." - Benjamin Franklin.

[SATtva]

Yep. https://xkcd.com/538/

[Carbonflux]

Baaaahahahaaa! xkcd is just brilliant, who is this cartoonist with such wisdom, it seems like there is always a cartoon for every case.

[filanwizard]

Quite true, No matter how secure something is there is always the human factor and humans can be socially engineered to give up information. either through direct interrogation or through pure smart social engineering.

This is how some of the worlds most secure systems have actually been hacked. Someone calls the right person and hammers off a series of questions and the hackers who are good can assemble that info into the password if they did not simply get it outright.

[B.Y.O.B.]

Baaaahahahaaa! xkcd is just brilliant, who is this cartoonist with such wisdom, it seems like there is always a cartoon for every case.

Exactly my thoughts about this site

[Pilchard123]

I do love xkcd, particularly the "film/interesting science" VS "real science" strips.

http://xkcd.com/683/
http://xkcd.com/242/

EDIT: Vaguely on-topic, I know nowt about QC stuff, other that a while ago they had a 7-qubit adder or something.

[neroe23[TheOne]]

Mini-necro, but here is what I've found. Looks more like scientific trolling than real stuff.
http://www.dwavesys.com/en/dw_homepage.html

[SATtva]

Considering D-Wave and its adiabatic black box, i recommend you a recent blog post by Scott Aaronson, one of D-Wave's skeptics (sic).