Submitted by gregnoone t3_yrbcmo in Futurology

Hi guys - I wrote this piece exploring the current state of post-quantum encryption algorithms for Tech Monitor, and the extent to which they'd actually be able to resist the computational onslaught of mature quantum computers when they eventually emerge (spoilers: a lot of them can't seem to resist classical computers.) As a community with a keen interest in the future of online security, I'd be keen to read your thoughts on the subject. Cheers!

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missinglinknz t1_ivsx29d wrote

Great article, very thorough and thoughtful.

The idea of "harvest now, decrypt later" attacks is terrifying!

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gregnoone OP t1_ivt4jk0 wrote

that's really kind! thanks so much. and yes, completely agree re: HNDL attacks. the idea that so much of the data we've encrypted now is so vulnerable, even though it'll likely only be cracked open in a few decades time, is one i find personally fascinating.

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OliverSparrow t1_ivu625h wrote

Any encryption scheme is algorithmic can be undone with sufficient time and crunch. Current schemes rely on that time being long. It is hard to imagine any scheme that is not algorithmic that is also useful to Bob when Alice uses it. One time pads where the "key" fires off a distinct algorithm are not easily decryptable: caustic schemes for example. You just need a lotta lotta pads to service the internet base.

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Ancient-Sense-2022 t1_ivv62yf wrote

There are studies of Quantum Nonlocality (Quantum Entanglement) that would allow to send encrypt communications and arrive before the communication was sent. Just a fraction of a nano second in the past. “Past” as defined in the Theory of Relativity by Albert Einstein.

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UniversalMomentum t1_ivvxhry wrote

There's no sign that quantum computing is about to become viable for breaking most encryption.

It's much easier to keep current encryption levels up thanit is to make quantum chips.

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gregnoone OP t1_ivxaek7 wrote

Agreed - I'm personally a bit sceptical at the estimates saying it'll be the end of the decade for a mature quantum computer to be built, much less in 20 years' time. But I am convinced that it will happen, and given the long shelf-life of some of the data that's being encrypted now, and its vulnerability to HNDL attacks, I think the argument for coming up with durable post-quantum encryption algos now is actually quite prudent.

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ItsAConspiracy t1_ivxwu97 wrote

For a while, physicists put a lot of work into figuring out whether quantum entanglement would allow faster-than-light communication (which is what would allow messages into the past). They ended up with a proof that it would never work.

Basically, entanglement means you have two coins, such that if you flip one and it comes up heads, the other will come up tails. But you can't make the first coin come up the way you want, it's just random. There's no way to use it to send a message.

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Ancient-Sense-2022 t1_ivyk4tt wrote

Let’s take the 2 coins sample, it doesn’t matter how much apart they are from each other (ei: 100 Lights years away), when you flip one coin, the other one flips “at the same time”.
I said “at the same time” because it is to believe that the time transpire between the event of flip one coin and the reaction of the other coin flipping is zero (Quantum Entanglement).
Now if you take into account that a particle of light travels at 299,792,458 meters per second, cannot reproduce the results of Quantum Nonlocality.
Now, we know everything we see is the past, the time that transpire for a particle of light to bounced on an object into our eyes, makes the image in our eyes an old image.
A particle of light coming from the Sun takes about 8 minutes to arrive to earth. Basically when we see the position of Sun, we see 8 minutes into the past.
So if you are avail to send a communication as a Quantum Nonlocality event, your communication was sent “at the same time”, but we will perceiving to receive the communication in the present. However, we are actually getting the communication in the past as described in Albert Einstein’s Theory of Relativity.

In other words, if we can used Quantum Nonlocality, we could see the position of the Sun 8 minutes into the future.

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Ancient-Sense-2022 t1_iw1ax9a wrote

My bad, I thought you knew what is Quantum Entanglement since you mentioned in your comment.
Quantum Entanglement is when two particles link together in a certain way no matter how far apart they are in space. If you move one particle to the right, the other particle moves to the left instantaneously, even if separated by billions of light-years (simple explanation).
I thought you were using 2 coins to represent 2 particles.

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gsvnvariable t1_iw2avox wrote

Is that different than IBM’s System Two and their goal of 4k qubit machine in 2025 and then linking more together for 16k+ ? I’m learning about all this so I’m not quite up to speed

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ItsAConspiracy t1_iw2bu6g wrote

No that is not how quantum entanglement works. Here's the standard example of how it works:

Electrons have a property called "spin." You can measure the spin and it will have a value of either "up" or "down."

The spin is in an indeterminate state until you measure it. Then when you measure, it will be either up or down, randomly. If two particles are entangled, then if you measure one and find that it's up, you already know that the other one is down.

But if you're that second person and haven't been tipped off by the first person, then you still just have an electron with a spin you don't know. So you'll measure it and find out that it happens to be down. Now you know the other one is up. But it's still just a random value.

Quantum entanglement does not cause particles to move around like you described.

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