After coming out of the laboratory, Lu Zhou gestured to Xue Xueshi for a while, then looked at the two security guards standing at the door and shouted in a serious tone.

"Adjust the level of confidentiality here to Class A, unless it is me, no one should be near here."

The two security guards stood up and raised their hands in a clean manner.

"Yes."

After leaving the Semiconductor Research Institute, Academician Xue looked at Lu Zhou, who was walking next to him.

"They are the people of the army?"

Lu Zhou: "I have a good relationship with their heads when I am retired. I will help arrange my work."

From the army, at least the political review does not require him to worry about, and the leader of the political review is not recommended to him. Moreover, in terms of security capabilities, the people coming out of the army are far more powerful than those recruited by the general channels. Even the basic training can be saved, and they can be employed directly.

From the establishment of the Jinling Institute of Advanced Studies to the present, let alone the criminal cases of material theft, even a piece of draft paper has not been lost, relying on these lovely people who are dedicated to their duties.

With Xue Xueshi came to the office, Lu Zhou told the secretary to pour him a cup of tea and pour himself a cup of coffee.

After doing these things, the secretary left the office with great interest and took the door with ease.

Looking at the door closed, Lu Zhou continued to look at the old gentleman sitting opposite him, smiled and said.

"I guess you have a lot of things to ask, please ask first."

Academician Xue was silent for a while, and sighed softly.

"I did have a lot of confusion before coming here, but now... I feel I have got the answer. What's more..."

The old academician’s smile brought a touch of complex feeling.

"...cryptography, you can already withdraw from the stage of history."

Lu Zhou shook his head.

"This is too absolute. It takes time to upgrade any technology. Just like even a clean and efficient energy source like fusion energy, coal power still accounts for this small part of the market in our western region... ”

"Under the circumstances, the exit of the historical stage is only the use of encryption algorithms in long-distance communication, in the short-distance communication from base stations to individuals, and other fields, cryptography can still play a significant role ..."

After a pause, Lu Zhou looked at Xue Xueshi and continued.

"...and all that is needed is to make some adjustments."

Cheering the words of Lu Zhou repeatedly, Xue Academician fell into meditation.

Did not disturb his thinking, Lu Zhou picked up the coffee cup, blew the white mist, and took a slow drink.

After about five minutes, Xue Xueshi finally raised his head and said seriously.

"Is there anything I can do to help?"

Lu Zhou’s face showed a smile of approval.

"of course."

“I have a few questions and I need to consult experts in related fields.”

Academician Xue: "Which aspect?"

"About quantum communication."

Upon hearing this sentence, Academician Xue slightly squatted, his expression slightly embarrassed and said: "Quantum communication... I am not an expert in this area, you should look for a professor at HKUST..."

"Before you came here, I had already sent the mail and the professor of the University of Science and Technology passed, and after hearing my question, they recommended it to you."

Looking at Xue Xueshi, Lu Zhou continued, "In addition to cryptography, you are also an expert in the field of communications engineering. He used to be a senior engineer at China Electronics 46 and participated in the construction of early domestic fiber networks."

After hearing these nostalgic things, Xue Academician floated a few memories.

But in the end, he still shook his head.

"That is all the old things. I have basically moved to the direction of communication security since 10 years. I am afraid it will be difficult to help you."

"But I believe that this kind of experience is not outdated," Lu Zhou said seriously, "especially when we need to re-establish this communication network."

At the moment of hearing this sentence, Xue Academician’s heart was shocked and he couldn’t believe to look at Lu Zhou.

"What do you mean, you intend... Are you going to use that kind of quantum fiber? Re-establishing a domestic communication network?"

"This is not my plan."

Looking at the sound has begun to incoherent Xue Academician, Lu Zhou smiled and said in a joking tone.

"And, I have not said that it is only domestic."

......

Once the problem of quantum repeaters is solved, the entire quantum communication technology has been commercially available.

However, quantum communication technology has a very fatal shortcoming, which is the amount of data transmitted in a unit of time.

Take the submarine cable from the west coast of the United States to the east coast of China as an example. The bandwidth is measured in units of tbps.

Data of this size is not difficult for traditional fiber optics. However, for quantum communication technology that relies on single photon entanglement to achieve information transmission, this is a problem that cannot be solved in a short period of time.

To put it simply, the communication channel based on quantum communication technology is no problem to meet the data exchange between a limited number of enterprises, but it cannot carry the communication of this size on the Internet.

However, this is not the solution.

According to the report of istfp5, a 128-bit key can guarantee the security of 100 gbit data. In theory, only a quantum communication channel with a bandwidth of up to the order of mtps is needed, which is enough to add a lock to all information across the Pacific.

Therefore, a perfect solution is to combine traditional communication means with quantum communication technology, use the traditional communication channel to send "locked" information, and then use the quantum communication channel to distribute the "unlocked" key.

The abstract description is that the big hand sends the parcel and the small hand hands the key.

This kind of encryption method similar to "one time and one secret" can theoretically achieve the degree of "unconditional security". If the key to unlock is unique, then no matter how fast the computer is, it is impossible to steal the key by simple computing power.

In order to achieve the separation of the key and the encrypted information, a new communication protocol is needed to implement. Not only that, in order to improve the efficiency of information transmission, the quantum communication network used to distribute keys must be rigorously designed.

It must be admitted that this is not an easy job.

But in any case, compared to quantum repeaters, it is still much easier.

There was hardly any hesitation. Xue Xueshi took the invitation of Lu Zhou on the spot and participated in the project of building a quantum communication network. He stayed at Jinling University in the name of visiting exchanges.

Just right, he is still worried about how to avoid the colleagues and old friends who are waiting for him to go to the Ministry of Industry and Information.

Although it is easy to control your mouth, the industry circle in which he is engaged is really too small.

A lot of things, even if he doesn't say anything, one eye has guessed anything.

Whether it is for the big picture or for himself, leaving for a while is the best choice...

With the addition of Xue Academician, the speed of advancement of the entire quantum communication network project can be described as speed. With the experience of this old gentleman, Lu Zhou quickly found an optimal method for combining quantum communication technology with traditional communication technology and completed a structural framework for this new communication protocol.

In this way, time passed, and finally arrived at the last day of April.

An experimental quantum communication pipeline with a length of about 500 meters was built at the concealed corner of the Jinling Institute of Advanced Studies. At the same time, this ivory tower standing at the top of the Chinese academic community also ushered in a special guest...

Light pen