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# The future of ciphers

When one day, a man sits down to analyze everything that computers have affected (and by default, improved) in the existence of the human race, that man would be doomed - that work would never get done completely. We’re saving ourselves and you a lot of time by not going into the details of the issue, but lets just say that computers are awesome, and leave it at that. So, ciphers. To give you an idea of what was ‘groundbreaking’ in ancient times, try cracking this.

**THE FUTURE OF CIPHERS**

**Change is the only constant, because nothing else can afford to stop**

**What Ciphers Used To Be**

When one day, a man sits down to analyze everything that computers have affected (and by default, improved) in the existence of the human race, that man would be doomed - that work would never get done completely. We’re saving ourselves and you a lot of time by not going into the details of the issue, but lets just say that computers are awesome, and leave it at that. So, ciphers. To give you an idea of what was ‘groundbreaking’ in ancient times, try cracking this.

L ORYB GLJLW.

We would’ve loved to see your chain of thought here, but let’s get to the point here. That meant:

I LOVE DIGIT.

Look closely, and you’ll see that all we’ve done is shift the alphabets by 3. You might now remember this from the general quizzes to took as a child. Now this exact code is said to have a great history - people claim that Caesar himself devised this, and used it to keep his political adversaries from understanding his messages across the empire, even if they got hold of the message. Now, this code may have proved effective then, but this code has scarcely fooled anyone since. But it continued to be used, because the main area of application of cryptology in olden times was the battlefield, and in devising a new code, many areas are to be considered, not least the intelligence of the man who sits to write down the encoded message. Too complex, and the sender might mess up the sending, or the receiver might mess up understanding. Enter, the computer.

**What Ciphers Are Today**

If Caesar was a proud man, he would feel incredibly belittled by the heights that a field that he was one of the chief propagators of, has reached. Where we stand today, the kind of algorithms that are used to secure our world would take the brute force attacks anywhere between 1010-1020 years to crack. Did we mention that it would take the parallel processing power of all the computers in the world, along with mobile, laptops, tablets, and everything else that says 1+1=2. Yeah, it all seem well and good for as long as we talk in such grand scale of things. There is one problem, though. And it is a huge problem. It is...

**Cryptography in a Quantum World**

Ah, well. Finally we get to discuss this issue in some detail. Last month, we gave you a teaser of the capabilities of Quantum sciences in the ‘How Safe is Your Online Transaction?’ chapter in the Fast Track to E-commerce. Now is the time we get down to what exactly prompted us to speculate of such unpredictable times.

So, at the last page, we left the issue of computers at ‘computers are awesome’. Well, they are. But they’re not as awesome as they can be. Not yet. Let us treat you with an example here. We give you a number. Say, 287. Now, we tell you to factorize it. Those of you who do not get chills solving class 5th problem at this point (need not worry if you are in class 5th right now, though), might come up with something like 210+33. Good on you, sir. What you did was absolutely incredible, if we’re talking in terms of computing power. This is called the factorization problem, and this (though not in such an easy form, obviously) is what is used in all forms of cryptography known to you. Because, as it turns out, our computers cannot factorize that well. In the grand scale of things, they cannot do it at all. And that’s why RSA loves this problem - so much so that their entire work model is structured around this problem. That is the reason the world fears Quantum Computing as much as it lusts for it. The moment someone announces that a full fledged quantum computer has been built, panic would ensue across everything that is based on money and the internet. So basically the global economy.

Why, you ask? Well, as it turns out, a computer that can use qubits (quantum bits) instead of bits can crack this problem in about as much time as it took you to read the last word of this sentence. Interested (and really really smart)? Check out Shor’s algorithm for prime factoring. Really, please do. There are few mathematical formulae in the world that can bring it to its knees the moment one knows how to use them. No kidding.

**Quantum Cryptography**

We might not have built a quantum computer, but the field has seen incredible advancements, and today you can possibly use quantum techniques in your friendly neighbourhood ciphers. Let us take, for example, something called the BB84 cryptography protocol. The super stripped-down idea is that if Alice wants to send data to Bob (because apparently, when it comes to a quantum situation needing 2 people, it is always Alice and Bob), what would be done is that Alice would encode her data in qubits (something like photons - the light particles), and send them to Bob in some arbitrary bases. Now, Bob would receive the inflow in some arbitrary bases of his choice. His results would be phased by the difference of bases chosen by him and those chosen by Alice. This problem, though can easily be corrected by a simple communication to clear the air on this topic. Oh, and forget about eavesdropping, because if a third listener tried to copy the data with them, it would not be allowed. The network won’t stop him, and neither would Bob or Alice. That’s because they don’t need to - the Universe is on it already. It is impossible to copy quantum bits exactly.

**Post-Quantum Cryptography**

There are many, many allegations that you might throw at mankind, and most of them would probably be true. But one thing that you can never say that humans lack is vision. Yes, today’s attempts at Quantum Computing are a far cry from the kind that would be needed in order to tackle the awesome power bursting from the proper concept that is Quantum Computing. But because no concept would ever be allowed to run loose in today’s world, counterideas for the force of Quantum Computing are topics of hot debate, and of course, research. It is well known that unless we stumble upon another hitherto unforeseen blockage in nature (we’re looking at you Heisenberg Principle), Quantum Computers would make it through. That day might not be today, and it might not be tomorrow, but it will be here someday.

And if a power exists, we need to consider that it will be used for at least some sort of evil, especially when it holds such never-seen-before capabilities. Consider this: the moment the day comes that a Quantum Computer is announced to the world, RSA is dead, DSA is dead; hyperbolic, elliptic, hyperelliptic, and every other curve based encryption technique is dead. And if we really want to make sure that every form of data protection technique known to man is not dead with all of that, we need to find remedies. And we need to find them now.

There are some ideas in that space in existence, though. These include:

**1. Hash based cryptography**

If you have any background in computer science, you might have heard of hash tables. And if you have some serious background, you probably love them, like some of us. To hear that these little things are quantum proof in the broad sense is a huge relief. Yes, folks, hashing would survive even in the era of quantum computers, because the idea here is that we shouldn’t be solely reliant on a secret trapdoor functions to produce our keys for us. Then again, if random number based keys are the only hope for the future, then it might not be that great after all.

**2. Code based cryptography**

Wild Goppa codes are codes over small finite fields GF(q) obtained from Goppa polynomials (yes, that name). While the whole process of polynomial based cryptography is as old as our regular, everyday public key systems, they are rarely used due to the unreal key lengths they produce, in comparison to the much loved (and feared) RSA.

**3. Lattice based cryptography**

As you might have guessed, this kind of cryptography is based on lattice study. And there is no easy way to say this, but a lattice L is the set of points in an n-dimensional Euclidean space, Rn, each with unique basis. If you must know, a basis of L is a bunch of vectors, uniquely represented as a set of numerical coefficients.

If you find these terms to be challenging/interesting/overwhelming/all of these, we suggest that you look it up yourself, because not only is it beyond the scope of the topic, but also this chapter, and the FastTrack itself. But, it is interesting, nevertheless. We, here, spent quite a few afternoons going through this incredible pool of knowledge ourselves.

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