Hold onto my secrets, dear entangled light

Part I: Where they talk about ‘secret codes’ in general

Minnie and DivZ (pronounced Div Zee) were talking one afternoon.

Minnie was in a secretive mood. Minnie said to DivZ ‘Hey, let’s meet somewhere in secret. I will give you the details in code.’

Nffu zpv jo qbsl bu fjhiu qn

DivZ glanced and immediately recognized it. It was a simple code where A became B, B became C, and so on. She quickly substituted the letters and said, “Alright Minnie, I will meet you in the park at 8.00 tonight”.

DivZ:

‘It takes a small percentage of our brain to crack this simple code. Alan Turing invented the valve-based computer to crack the Enigma code and it helped the Allies win the war.’

Minnie:

‘That was decades back. Now, we are safe with all the encryption right? Each message we send is encrypted by a 256-digit code and sent out. Only our private key can open it. I read that computers will take 1000s of years to crack the code. Don’t worry about your bank details being hacked en route.

DivZ:

What if I tell you that the quantum computers that are around the corner, could crack AES encryption in just a few hours? Quantum Computers are really good at tasks like guessing a long sequence of digits.

Minnie:

Which means, there are no secrets? Any code can be broken open? Wow, I am freaking out, will my parents be able to read my boyfriend’s email message?

part II: the implications of cracking open secrets

DivZ:

Ha ha Minnie, always worried about your little shenanigans.

Imagine the secrets of companies – their plans, new products, source codes, and market strategies. If you can crack the (AES) encryption, competitors can read them all en route, like a page of an open book.

And imagine countries? What will happen to military plans and new weapon designs that are stored in encrypted servers? Can’t those secrets be cracked open also?

Minnie:

That’s a dangerous world, a world with no secrets. WhatsApp says their messages are end-to-end encrypted, ain’t it safe then?

DivZ:

That’s what I am saying. Forget about your latest WhatsApp forward. It is not worth the bit it is written with. What happens if someone else on the net drives off your Tesla?

Or worse.

Imagine a signal to a HIMAR (High Mobility Artillery Rocket System) weapon system sent from Ukraine to hit on a Russian armament dump. It is coordinated to hit a precise GPS location in say Dombas, through satellites.

What if Russia can capture that signal and read the message in transit? And use a quantum computer to crack the encrypted code.  

Russia can start making adjustments to the war plans. Further, what if Russia can crack the encryption of the satellite and start mimicking the satellite itself. Suddenly, the HIMARs could turn around and start hitting Keiv.

Secret worlds are dangerous. Secretless worlds are destructive. You pick your peril.

Minnie:

You always think of extreme scenarios DivZ. Isn’t going to happen.

DivZ:

Today, quantum computers are not fully active. But, you know what, governments are sucking up encrypted communication from rival governments and are storing them. Even though they can’t make anything out of them. Today.

They know quantum computers are around the corner. They think ‘this is useless now, but in about a decade, we will have access to quantum computers. We can then can crack open these messages. They might still be valuable.’

Think of a US submarine’s design. It will be valuable for Russia, even if it gets its hand on it a decade from now.

Today’s communication needs to be encrypted by today’s computers in such a way that even future computers cannot crack them.

That is the encryption computing paradox.

part III: Let us encrypt using physics rather than maths

Minnie:

A world without secrets, that is scary. Unimaginable DivZ. Let us change the subject.

DivZ:

You are bang on. Changing the subject is absolutely the right approach Minnie.

If you use Maths to encrypt your messages over the Internet, bigger and bigger computers can come in and crack the code. We have to use Physics to generate the code. Then no one can crack it.

Minnie:

Now you are outright weird. Use Physics for generating codes?

DivZ:

Yeah, you heard of Aspect, Zeilinger, and Clauser. These Physicists got the noble prize for ‘Quantum Entanglement’ in 2022. With Quantum Entanglement you can create codes that no one can crack!

Quantum Entanglement (QE) has been known for over a century now. Einstein wrote a paper on it too (EPR Paper), and said it is ‘Spooky Action at a Distance.’ These scientists, devised wickedly clever experiments to prove that Quantum Entanglement indeed exists.

Minnie:

What is Quantum Entanglement (QE) then? I am now curious.

part IV: kindred particles – till observation do we part:

DivZ:

Suppose you have two dice in two closed boxes. These boxes are then moved miles apart. Can you assure that if one of the dice is 4, the other one is also a 4? Not at all.

When it comes to smaller objects, like electrons, neutrons, bosons, and in this case Photons, the world is different. You can entangle two of these smallies together. Once entangled, they will become connected, kindred souls.

Imagine two closed boxes containing one Photon each, from an entangled pair. Open one box, and you find that the Photon is spinning in one way (1 or 0), you can very readily say, even without opening the other box, that the other Photon in the other box is spinning the other way (0 or 1).

This is a certainity, even if the boxes are moved to the opposite ends of the galaxy (before opening and observing them)

The movement or the distance will not alter this. This is called Quantum Entanglement.

Einstein found it bizarre. The 2022 Noble laureates worked out the reason. When the two Photons get entangled, they become part of the same wave function. Hence they remain paired.

Minnie:

You know, that’s why I tell my friends not to get entangled. How do you generate these defanged, entangled Photons? And how do you move them around?

DivZ:

It turns out that generating these ‘entangled pairs’ is an easy enough exercise. NASA says that there are many ways to do it, including moving two Photons close to each other at low temperatures or bombarding them in pairs over non-linear crystals.

You can move these entangled photons quite easily too. You can move them inside a fiber optic cable or even through space. Distance and sunlight (being a river of Photons, by itself) do affect the entanglement. But, Scotty, you can pretty much beam one of the entangled photons from a satellite, through space, to a ground station in the night.

China is ahead in this race of the Entangled Photon movement. They even have a satellite that communicates to the ground station with EPs. That has got the Western governments worried. In a future world, China can read the West’s secrets, but the West fears that they cannot hear the ‘Chinese Whisper’.

Minnie:

So, how do you hash up secrets through these photons?

WinZ:

Turns out, that is pretty easy to imagine. Suppose a Chinese satellite has got a secret photo of US Government facilities at Los Alamos. The photo has to be secretly transmitted to the ground station in Qingdao, China.

The satellite comes above the ground station in the line of sight, deep in the night.

The satellite generates 512 pairs of randomly entangled photons by bombarding Photons on a non-linear crystal onboard. It uses one of the pair sequences for encrypting the secret photo. And it sends the other entangled pair sequence, through space, to the ground station.

The ground station first receives these 512 photons (or bits). Now, due to the property of QE, it can accurately guess the unique encryption sequence used in the satellite. (Treat all 0 as 1 and 1 and 0). The ground station confirms the receipt of the code and asks the satellite to send out the picture.

Then the Ground Station receives the encrypted picture and uses this unique, one-time code to decrypt the message. And voila, the Chinese securely get that research vehicle photograph for their analysis.

So, unlike a conventional system where the encryption sequences are fixed and can be reverse-engineered by Quantum Computers, with QE, the encryption sequences are just in time, every time.

part V: THE UNCERTAINTY IS THE SOURCE OF CERTAINTY

Minnie:

It is not so easy WinZ. What if an American vehicle is parked near the ground station. It can read the sequence also. And crack the entire code.

WinZ:

Now, as per the Uncertainty Principle, if you observe a particle and measure its angular momentum (spin, in our case 0 or 1), then the spin of the particle is unpredictably altered.

Once observed by the US spy mid-way, the Heisenberg’s principle of Uncertainty jumps in. The very act of observation itself changes the property of the photon. This phenomena is used to ensure no one else can access the code.

Now, along with the encryption sequence, the satellite also sends a pre-known sign-off sequence. If the US spy near the ground station reads the secret code through the photon stream, the secret code is altered. Then the sign-off sequence is also altered, forever. When the ground station notices the alteration in the sign-off code, it knows that the secret code has been compromised. It will ask the satellite not to send out the encrypted file.

So, uncertainty is the only certain path to certainty.

Minnie:

So, you are saying with QE, in the future we can generate a 512-digit encryption code securely, in real-time, every time. And like Mission Impossible, the message will self-destruct if anyone else reads the sequence en route? And this is possible because the encryption depends on Physical processes rather than mathematical codes.

WinZ

Exactly Minnie, no one else can summarise it better. Now companies like Microsoft and Google have big interests in security and are racing towards Quantum Entanglement technologies for encryption.

There are many ways this scheme can go wrong. The ability to transport the entangled Photons is lossy. Cracking the ‘sign-off’ sequence can give the spy a back door entry. The Photon entanglement grid might not be random after all. Scientists are still working on all these problems.

It will take many decades for the existing systems to switch over to quantum encryption. But over time, the world will start using Physics rather than Maths to maintain its secrets.

Minnie:

Huh, Physics, Maths… these are concepts created by our human minds. Unencumbered by such simple insularities, the Universe lumbers on with its business anyways, can you say?

WinZ:

< For once, speechless >.

The current encryption standards are inadequate in the future world of Qubits and Quantum Computing.

With Quantum Computers AES256 can be broken in days. Secret communications can become open books.

Countries and corporations are now working on encrypting messages through Quantum Entanglement with Photons. Once entangled, a pair of Protons to maintain their ‘relationship’ even if they are galaxies apart.

One set of the entangled Protons can be used to encrypt the message. The other corresponding set can be transported through fibre optic cables or through space. They can be used to decrypt the message at the receiving end.

These codes cannot be read by a third party observer en route as it is protected by the ‘Principle of Uncertainity’. Just reading those codes change them.