In fact, according to Kyosuke Takasaka, they knew from the beginning that the so-called absolutely secure means of communication was a false proposition from the beginning. Pen % fun % Pavilion www.biquge.info

But if they don't try, how can they be willing. So the research then rightfully fell into a bottleneck. But at this moment, someone came up with an idea to break the deadlock!

"If we are so careful about being spied on, wouldn't it be nice if we developed a system that would be discovered as soon as someone was snooping?"

This may seem like a fantasy to outsiders, but it is undoubtedly a very practical idea in the secret research and development department of amalgam.

Because of two very famous theories of quantum physics - the "observer effect" and the "uncertainty principle"!

The former means that there is little we can do without affecting what we observe—just to varying degrees.

The latter is to say that when we want to measure an object, the act of measuring something first will inevitably disturb that thing and thus change its state; Second, because the quantum world is not concrete, there are deeper and more fundamental limitations to precisely determining the state of a particle based on probability.

It seems like the two theories are similar, right? But in reality, the two of them are not the same thing. Although you will often encounter misunderstandings and misuses of these two concepts.

If the distinction between the two were to be succinct, the former would focus on the act of "observing", while the latter would focus on the results of "measurement".

In fact, these two theories later extended many hypotheses, the most famous of which is the "PANCI unpredictability theory" proposed by the cat madman - Schrödinger (who currently enjoys a special allowance from the Institute of Amalgam Physics for his outstanding contributions to the world of gentlemen - artificial AI dog headphones) at the 18th Amalgam Conference on Science and Technology - that is, if you don't open the absolute realm, you don't know whether the blue and white bar, pure white, or big JJ are hidden underneath.

Now, according to the principle of the observer effect ...

Mr. Seamus: "Hey! Dead sister control! You've changed the subject a little stiffly! ”

Kyosuke Takasaka ignored his interruption and continued:

Since when we observe quanta, we will change the quanta because of this behavior, then when we store the communication data in a series of quanta according to a certain law, such as light waves, if someone wants to crack it, no matter how we observe, it will cause changes to the original quantum information.

This inevitably affects the interpretation of the data, but what if the regularity of the observation itself is also taken into account? Isn't it possible to devise a means of transmitting information that can only be interpreted in a specific way? And this correct interpretation is still a one-time thing, because as long as it is observed once, the original quantum information will be changed.

By the time I tried to interpret it a second time, the original quantum information had already changed. In this way, it can not only ensure the security of information transmission, but also find out whether the information is leaked in time.

Because if you use the right way to interpret quantum information and find that it can't be solved, then there is only one possibility, this information has already been interpreted by others!

The above is the theoretical basis for the quantum cryptography developed by amalgam.

So what does it look like?

Some physicists have proposed the following system:

Suppose two people want to exchange information securely, and these two people are A and B. A initializes the message by sending B a key, which may be the pattern of encrypting the data message - telling B that the next message is encrypted.

This key is an arbitrary sequence of bits, sent in some type pattern, which can be thought of as two different initial values representing a particular binary bit (0 or 1).

For the time being, consider this key value to be a stream of photons traveling in one direction, with each photon particle representing a single bit of data (0 or 1). In addition to running in a straight line, all the photons also vibrate in some way.

These vibrations occur in a space of 360 degrees along any axis, and for the sake of simplicity (at least in quantum cryptography to simplify the problem), these vibrations can be divided into four specific states, i.e., up, down, left, right, left, right, and right and left, and the angle of vibration is along the poles of the photon.

A special polarizer is then fabricated, which allows atoms in a certain vibrating state to pass through without any change, causing other atoms to pass through after changing the vibrating state.

If A has one or more polarizers that allow photons in these four states to pass through, then she can choose to filter along a straight line (top, bottom, left, right) or diagonally (top left, bottom right, top right, bottom left).

A switches her vibrational pattern between straight and diagonal lines to filter out individual photons that are transmitted at will. Each photon is the quantum information emitted by A, so that one of the two vibrational modes represents a single binary bit, such as 1 or 0.

When a photon is received, B must measure each photon bit with a straight or diagonal polarizer. He may or may choose the right polarization angle, or he may make a mistake.

Since A is very arbitrary when choosing a polarizer, how will the photons react when the wrong polarizer is chosen?

The uncertainty principle states that we cannot be sure what happens to each individual photon because we change its properties when we measure its behavior (if we want to measure two properties of a system, measuring one excludes our right to quantify the other). However, we can estimate what happened in this group.

When B measures upper/lower left/lower right and upper right/lower left (diagonal) photons with a linear sidelight device, the state of these photons changes as they pass through the polarizer, with half changing to an up-and-down vibration pattern and the other half to a left-right pattern. But we can't be sure which state a single photon will transition to.

So B may or may not be right when measuring photons, and it can be seen that A and B have created an insecure communication channel that other people may also be listening into.

But if next A tells B which polarizer she uses to send the photon bits, not how she polarizes the photons. For example, she might say that photon 8597 is (theoretically) sent in a straight line, but she won't say whether it is sent up, down, left or right.

B will then be able to determine how to use the correct polarizer to accept each photon. Then A and B discard all the photons they had measured with the wrong polarizer. So what they have is a sequence of 0s and 1s that are half the length of the original transmission. This forms the basis of the one-timepad (OTP) theory, i.e., once properly implemented, a cryptographic system that is considered completely arbitrary and secure. (To be continued.) )