An introduction to Quantum Key distribution (QKD). What are quantum keys and how can we use them?
Added: July 2020.
Suggested age range: 16+
Questions and answers
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Qubits, how do they work and how will they help change computational calculations?
A classical computer stores bits as either 0 or 1.
A quantum computer stores qubits in a mixed state where they can (i) be BOTH 0 and 1 at the same time and (ii) can be linked or entangled with all the other qubits in the computer.
So imagine a classical computer with 100 bits. IF each bit can be 0 or 1 then the total number of different states that these 100 bits could represent is given by 2^100. A HUGE number (your calculator won't be able to handle it). But the classical computer can only address ONE of these at a time because each of the 100 bits has to be either 0 or 1.
Imagine a quantum computer with 100 qubits. Now – all qubits are BOTH 0 and 1, and so the 2^100 states can ALL be represented simultaneously!! This compute power is FAR beyond anything that a classical computer could ever achieve. And it is still only 100 qubits!!
Two provisos:
There is only a very limited number of things you can do with an entangled ensemble of 100 qubits and this reduces the potential / means you have to be very cunning how you make use of this new power.
No one has yet managed to make a 100 qubit machine – but they will one day.
Curriculum links
GCSE to A level transition » Networking » Network hardware
Data and information » Encryption » What is encryption?
Data structues and algorithms » data structures » Arrays
