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Quantum Cryptography

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Minxie Villaver

on 26 September 2013

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Transcript of Quantum Cryptography

Quantum Cryptography
"Unbreakable" Cryptography

It's paramount when communicating sensitive information, and humans have invented some unusual ways to encode their conversations.
What the Enigma machine was used for is called..
Quantum cryptography uses photons to TRANSMIT A KEY. Once the key is transmitted, coding and encoding using the normal secret-key method can take place.
Encrypt a message in such a way that it would NEVER be read by anyone whose eyes it isn’t for!
Quantum cryptology is the first cryptology that safeguards against passive interception.
The GOAL of quantum cryptology is to THWART attempts by a THIRD PARTY to eavesdrop on the encrypted message.
The system is already in use in some expensive and high-profile setups, most notably in Geneva's banking sector, but it comes with SERIOUS LIMITATIONS.
In modern cryptology, Eve (E) can passively intercept Alice and Bob's encrypted message -- she can get her hands on the encrypted message and work to decode it without Bob and Alice knowing she has their message.
Until the 1990s, CRYPTOLOGY was based on
in World War II
It resembles a typewriter on steroids. This machine created one of the most difficult ciphers (encoded messages) of the pre-computer age.
This is the process of encoding (cryptography)
One example is..
and decoding (cryptoanalysis) information or messages (called plaintext)
Collectively, all of these processes combined are called
- a mathematical process or procedure
These algorithms are used in conjunction with a
a collection of bits (usually numbers)
There are two widely used methods of employing keys.
Public-key cryptology (PKC)
Secret-key cryptology (SKC)
In the public-key cryptology (PKC) method, a user chooses TWO interrelated keys. He lets anyone who wants to send him a message KNOW how to encode it using ONE key. He makes this key PUBLIC The other key he keeps to HIMSELF. In this manner, anyone can send the user an encoded message, but only the RECIPIENT of the encoded message KNOWS how to decode it. Even the person sending the message DOESN'T KNOW what code the user employs to decode it.
In both of these methods (and in all cryptology),
The sender (point A) is referred to as Alice.
Point B is known as Bob.
The other usual method of traditional cryptology is secret-key cryptology (SKC). In this method, only ONE key is used by both Bob and Alice. The SAME key is used to BOTH encode and decode the PLAINTEXT. Even the algorithm used in the encoding and decoding process can be announced over an unsecured channel. The code will remain uncracked as long as the key used remains secret.
TRADITIONAL CRYPTOLOGY is certainly clever, but as with all encoding methods in code-breaking history, it's being PHASED OUT.
The keys used to encode messages are so long that it would take a TRILLION years to crack one using conventional computers!
Quantum cryptography uses the properties of LIGHT to create effectively UNBREAKABLE encryption. Any attempt to tap in affects the signal and can be INSTANTLY DETECTED!
PHOTONS are some pretty amazing particles. They have no mass, they're the smallest measure of light, and they can exist in all of their possible states at once, called the..
wave function
This means that whatever direction a photon can spin in -- say, diagonally, vertically and horizontally -- it does all at once.
Light in this state is called UNPOLARIZED.
Mind-boggling? You bet.
But don't let this throw you off; EVEN QUANTUM PHYSICISTS are grappling with the implications of the wave function. Hahaha
So how do you attach information to a photon's spin?

But how does a photon become a key? How do you attach information to a photon's spin?
This is where binary code comes into play.
Each type of a photon's spin represents one piece of information -- usually a 1 or a 0, for binary code.
This code uses strings of 1s and 0s to create a coherent message.
For example, 11100100110 could correspond with h-e-l-l-o.
In cryptology, an eavesdropper is referred to as EVE.
The laser-based process only works over short distances, and it can only be used to connect two computers at a time.
“In this case, it doesn’t matter what technology the adversary has, they’ll never be able to break the laws of physics,” said physicist Richard Hughes of Los Alamos National Laboratory in New Mexico, who works on quantum cryptography.
Any encryption method will only be as secure as the humans running it, added Hughes. Whenever someone claims that a particular technology “is fundamentally unbreakable, people will say that’s snake oil,” he said. “Nothing is unbreakable.”
However, a new breakthrough, published this week in Nature, offers a way to solve the second problem, connecting as many as 64 computers in a setup they describe as a "quantum access network."
The breakthrough comes from an improved photon detector that can handle 1 billion photons per second, allowing it to manage photon streams from more than one computer at once.
That lets quantum engineers build networks on a more common hub-and-spoke model, potentially opening the door for more sophisticated quantum-powered networks in the future.
If you’ve got communications that absolutely cannot be intercepted — whether you’re a NSA whistleblower, the president of Mexico, or Coca-Cola — quantum cryptography is the way to go. <3
Thanks for veiwing this Prezi! :D
France Perez
Minxie Villaver
Jetherine Son
Full transcript