According to Heisenberg its meaning is that it is impossible to determine simultaneously both the position and velocity of an electron or any other particle with any degree of accuracy or certainty
Cryptography is basically the making and breaking of codes. So quantum cryptography is the making and breaking of codes using quantum physics.
At the moment, we use complicated maths equations to code important (and secret) information that we want to send around the place - things like banking details or credit card info. Now, these codes are really hard to break - so hard it would take millions of computers millions of hours to solve them. But if we end up with quantum computers (and we're heading that way pretty fast), these codes could be broken in moments. So we need to find a new way of encrypting our data to keep it safe, and the answer may well be quantum cryptography.
If you've read about quantum physics and quantum computing, you'll know that in the quantum world you can't measure something without changing it, and this quirk could be used to make the safest coding system around!
To use quantum cryptography, you firstly need a pair of photons (little packets of light). These photons must be "linked" at the quantum level. This way, if you do something to one (like measure its polarity for example), the other one will be affected. This pair of photons (or lots of pairs) can then be used to send the "key" for your code. If anyone, other than your receiver, tries to look at your photon key they'll change it and end up with nothing. Not only that, but you'll be able to tell that someone tried to hack into your system!
What is Quantum Computing?
So…Quantum Computing…yeah, what is it? Hey, some of us still have trouble with understanding just plain old computing , let alone the extra confusing quantum stuff. Quantum Computing can be a very confusing thing, that doesn’t mean we should ignore it and put in the too hard basket, because the applications for this are incredible.
In the future, quantum computing will allow us to do the work that millions of conventional computers would take millions of years of to do, in a fraction of a second. And Australians (surprise, surprise) are leading the way in this research. Good on us!
Quantum Computing relies quite heavily on something called quantum uncertainty, that just means you can’t know all the information about a quantum particle (eg. an electron) without changing it. It is impossible to measure both the position and momentum (movement) of a quantum particle at the same time.
In a conventional computer, information is stored as ‘bits’, 8bits = 1 byte, 1000 bytes = 1 megabyte…etc. Bits are either 1’s or 0’s, or On or Off. This is how the whole computer and digital thing works, using bits that are either on or not. The quantum bit or ‘quibit’ (pronounced kwibit) is a variation of this with the uncertainty thrown in. Quibits can be both 1 AND 0 at the same time, not one or the other, as well all the combinations of the other numbers in between. This makes an infinite amount of information that can be stored in just 1 quibit.
With this kind of computing power, the applications for high powered computing is enourmous. People used to talk about mobile phones having more computing power than NASA did to send people to the moon, imagine having that, and more, in one single bit!