Buzz, buzz.

In the middle of the night, Shi Tiezhu suddenly opened his eyes.

The darkness couldn't block his vision, the faint light of the Guanlan Heavenly Eye lit up, and Shi Tiezhu looked at the buzzer placed at the head of his bed.

Shi Tiexin woke up together: "What's wrong?" ”

"The frequency band we set, there is a signal." Shi Tiezhu pressed the button and turned off the buzzer: "The radio has captured a piece of information and has recorded it." ”

"Is there really a signal?!" Shi Tiexin was surprised: "There is also a third front here? ”

"The third front may not be there, but the encrypted frequency band will not disappear by itself, and it is possible for others to use this frequency band to communicate." Although it was the middle of the night, Shi Tiezhu did not feel sleepy at all.

On the one hand, he has long developed the habit of falling asleep at any time, waking up at any time, and being refreshed immediately when he wakes up. On the other hand, there is no big consumption in cultivation, and if you don't sleep, you won't sleep, nothing.

Third, he also raised some alarm.

"It's strange, who would use this near-field encryption band to communicate at such a time?" Shi Tiezhu put on his clothes and strode through the corridor to the radio room.

Sitting in front of the machine screen and taking a look, I did intercept a short message.

Very brief, so short that there are no words.

Visualize the content on the screen, and all that comes out are four dots, arranged at different distances and intervals. There are long or short, interrupted or continuous lines in the middle of the holes.

"It's a special encrypted telecom." Shi Tiezhu glanced at it and understood that he couldn't crack it, because he didn't know what the direction, distance, and interval between these small holes meant.

Shi Tiexin also frowned. Through Heizun, he also learned some encrypted communication methods, but obviously not the one in front of him.

So, what exactly does this inexplicable text message mean?

"It seems that we can only ask an expert."

Shi Tiexin: "Do you know the cryptographic expert?" ”

"It's not me, it's 'us', we know a super-notch cryptographic expert." Shi Tiezhu looked at the time: "It's almost five o'clock, she should wake up, let's wait a few minutes and pass." ”

At 5:15 in the morning, Shi Tiezhu knocked on Sister Mengmeng's door.

Shi Tiexin was wondering if it would be too early, and if he would be yelled at by calling the old lady up so early. As a result, as soon as I opened the door, I saw that Sister Mengmeng had been washed and dressed neatly, looking ready to go out to exercise.

Shi Tiexin was instantly shocked: "Does Sister Mengmeng get up so early every day?" ”

"I'm too old to sleep. Besides, we were all waiting for the day, and we often gathered urgently and ran from long distances, so we were used to getting up early. Shi Tiezhu explained two sentences in his heart, and then showed a well-behaved expression to Sister Mengmeng: "Political commissar, early." ”

"Rare, do you know to come and see me?" Sister Mengmeng shook her arms as she spoke, looking like she was going to do a period of middle-aged and elderly health eight brocades at any time: "It's early in the morning, what's the matter?" ”

"I intercepted a ciphertext, I can't decipher it, you can help me take a look."

"You? Interception of ciphertext? Sister Mengmeng couldn't help but be happy: "When did you have the ability to intercept the ciphertext?" ”

"Isn't this how long I've been able to endure lately, and I won't be able to do it before. Okay commissar, don't make fun of me, I feel that this encrypted communication is still quite strange, you can take a look, don't make a mistake. ”

"Okay, bring it." The efficiency of the soldier is paramount, and Sister Mengmeng immediately began to study the small figure.

When she looked at it, her brow furrowed. I took out a pair of reading glasses again, squinted my eyes and looked at it carefully, looked up and down for two minutes, and suddenly said solemnly: "How did this secret message come from?" ”

Shi Tiezhu talked about the cause and effect. hid Shi Tiexin's situation and didn't mention it, only said that he went to the radio station to make fools and happened to catch the frequency band.

"Happened to bump into? You're too coincidental, isn't it? "Sister Mengmeng obviously doesn't believe it. But after thinking about it, she shook her head again: "No, you can't know this frequency band, maybe you really happened to bump into it." ”

An exclamation mark lit up on Shi Tiexin's head. Listening to the meaning of Sister Mengmeng, what is the origin of co-authoring this frequency band itself?

Hurriedly urged Shi Tiezhu to ask.

Shi Tiezhu: "Sister Mengmeng, what else is wrong with this frequency band?" ”

"This matter is secret, but since you have caught up, it doesn't hurt to tell you, this is the emergency communication frequency band of the Secret Bureau."

Shi Tiezhu frowned: "Secret Bureau? ”

"The Secret Bureau is a secret intelligence unit in our country, deeper than other intelligence agencies, and has made great contributions during the anti-imperialist war, but few people know about its existence."

"At that time, in order to allow high-speed transmission, high-speed docking, and high-speed response of intelligence and operations, I also had contact with people from the Secret Bureau. Many of the missions we carry out have intelligence support from the Secret Bureau, which can be said to be a very reliable group of underground fighters. ”

"But why did the people from the Secret Bureau come to Mars?"

"And now that the times have long changed, even if the Secret Bureau has news that needs to be sent back to Earth, it shouldn't use near-field communication."

"Is it a prank?"

"No, it can't be, this is the third ciphertext of the Secret Bureau, which is the result of the research of top linguists, mathematicians, graphicists, and cryptologists, with the characteristics of ultra-small size, ultra-high density, and super concealment, which ordinary members of the Secret Bureau can't touch or master, and it can't be a prank."

Sister Mengmeng looked at this symbol and said with a serious expression: "This kind of high-density information needs to be decompressed by special equipment, and files of different sizes will be decompressed according to the encryption method. There is no special equipment on the Advance, so it can only be calculated first with general equipment, which takes time. ”

"I'll give you a task, continue to listen to that band, and even all the other communication bands."

"If there's any trouble, report it immediately!"

Sister Mengmeng took off her sports jacket and put on her military uniform, and her whole person was sharp: "Shi Tiezhu first-class non-commissioned officer, we may have encountered some unexpected situations. Now, limited to you and me, enter a wartime state! Until there is a further change in the state of affairs, remember, act in secret. ”

Shi Tiezhu was awe-inspiring, and a standard upright: "Yes!" ”

Sister Mengmeng went to decipher the third ciphertext in a hurry, and she wanted to mobilize the computing power of the central computer of the advance number to crack it.

Shi Tiezhu went back to monitor the wireless frequency band. Until the state of affairs becomes clear, he must remain observant. You can't ask questions, you can't respond, so as to avoid exposing your own existence, which will lead to unpredictable changes.

There are no problems with the other bands, all communication is normal, except for this one band, which is strange.

Half an hour later, buzzing, the figure was monitored.

An hour later, buzzing, the figure was monitored again.

For the next two hours, the other party will send the same figure every half hour. Before it was deconstructed, the size of the information was only 46 bits, and it looked like an invisible ghost assassin in the vast telecommunications field.

"It's weird, it's not like what an intelligence agent should do when he contacts an organization." Shi Tiezhu pinched it and asked in his heart: "What do you think this behavior looks like?" ”

"It's like an intermittent flash of light in the middle of a dark wasteland, or a regular beating of gongs and drums in a fog." Shi Tiexin expressed his opinion: "I think this is a call for help, or a warning. ”

At this moment, Sister Mengmeng's communication came in: "Come to me immediately." ”