# Quantum encryption: How it works

Futurist Isaac Arthur explains how to stay safe from quantum encryption hacking.

Quantum encryption: How it works

Dan Patterson, a Senior Producer for CBS News and CNET, interviewed futurist Isaac Arthur about quantum encryption. The following is an edited transcript of the interview.

Isaac Arthur: We were using prime factorials--really large prime numbers--and factoring them as a way of doing encryption. Because again, that produces problems, where even a relatively simple one would require more processing to brute-force attack it than all the computers we have for the rest of the universe, running together. It just can't be done with classic computing.

With quantum computing, it's really easy. It's going to give you the result in about a second or two. It's not a magic wand, but for that particular example, it can crack it very easily.

An example we often like to use with this would be, if I put two cards on the table, I know what the two cards are, but I don't know which one's which. I only have to flip over one card to know what both cards are. If I put three cards out there, I have to flip over at least one card, and maybe another, to know what they all are. By the time we have 100 cards out there, it becomes so difficult to know what each one is, and you have to do so many flips, that it's going to--and this is a classic computing case--really bog down processing.

A quantum computer only ever has to flip over one card in that example, and it knows what all of them are. It gets the right answer there. That's going to screw with the prime factorial method of encryption, but there are many other ones we could use that would be safe against that. You'd only be vulnerable to quantum encryption hacking if it was being done before anyone made that changeover.

There are other methods we can use for encryption that are safe against quantum computing. We all just have to start switching over as these get better. I suspect we will know well in advance when that time comes.

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### By Dan Patterson

Dan is a writer, reporter, and producer. He is currently a reporter for at CBS News and was previously a Senior Writer for TechRepublic.