Linked by Hadrien Grasland on Sun 23rd Jan 2011 17:30 UTC, submitted by fran
Hardware, Embedded Systems "Scientists from Oxford University have made a significant step towards an ultrafast quantum computer by successfully generating 10 billion bits of quantum entanglement in silicon for the first time -- entanglement is the key ingredient that promises to make quantum computers far more powerful than conventional computing devices."
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RE[7]: Niche product?
by GeorgesBraque on Sun 23rd Jan 2011 22:11 UTC in reply to "RE[6]: Niche product?"
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The problem is when I try to go beyond that basic principle...

Moreover, extreme parallelism is more the realm of computers than it is the one of human minds. Trying to picture oneself what "You get a quantum machine to generate every possible alternate password and have them used AND changed all at the same time, at once, in a single instance." means in practice is difficult. How exactly could I be using several passwords at once ? I mean, as soon as an intruder measures my stored data, I have only used one single password on it, right ?

Guessing a password is not a computational problem, but decryption is. Suppose that your data is encrypted with a really really really hard to determine password. Also, suppose that there is a reasonably reliable test to determine when data is decrypted successfully.

With conventional computing devices, an attacker must try to guess your password. For every guess, he/she must attempt to decrypt your data and determine if the decryption is successful. This takes a lot of time and computing resources (this is essentially the justification for password encryption - decryption without knowing the password is too much trouble to be worth the time of an attacker).

A possible fear (and a valid one, IMHO) is that an attacker with a quantum computing device can skip the step of guessing your password. He/she can attempt decryption by all password possibilities simultaneously.

In this way, a whole level of complexity (and a whole order of magnitude) would be removed.

Make more sense?

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