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Quantum Computing and Optically Controlled Electrons
eldavojohn writes "Researchers have released a new paper on quantum computing theorizing how to use optically controlled electrons to make an ultrafast quantum computer. From the article, "Scientists have designed a scheme to create one of the fastest quantum computers to date using light pulses to rotate electron spins, which serve as quantum bits. This technique improves the overall clock rate of the quantum computer, which could lead to the fastest potentially scalable quantum computing scheme of which the scientists are aware.""
Because a quantum computer does fundamentally more at each clock.
Factoring an 1000-bigt integer takes CPU centuries on modern procesors but would be just afew million operations for a quantum computer.
Quantum Cryptography in that case is using the normal cryptographic method , just use a secure line to exchange the private key. But once the data are stored and the public key is known, it does not matter whether the private key has been transmitted on secure line or NOT. It is only a matter of cracking the crypto-algorithm itself which is then as weak against quantum computer factorisation. The only way to avoid that would be to get ride of public/private key system altogether, and use an OTP as key transmitted on a secure QC line.
But in the very end, QC is only a way of transmission without eavesdropping. It is NOT an encryption algorithm.
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Don't get too excited-- most quantum computing ideas are rather far-fetched-- there are really hard roadblocks that are theoretically and practically very hard to solve. The basic one is you have to keep all the electrons from interacting in ANY WAY with the rest of the universes for a considerable length of time (on the quantum scale). The slightest interaction with anything else and the quantum magic goes *poof*.