Double-Cut During the War of Resistance: My Wife Came from 1937

"1946?"

Commissar Luo calculated, "It's 1937 now, which means that in less than 10 years, there will be computers on the other side of the Pacific?"

"The United States today truly has an amazing level of industrial development and technology!"

Upon hearing this, Deputy Division Commander Xu laughed and said, "So what? Don't we now have computers that are even more advanced than theirs?"

"Comrade Hongwei!"

Deputy Division Commander Xiao asked with a smile, "Could you show us what this computer actually looks like?"

As far as he knew, even the atomic bomb was created in just 45 years.

This computer appeared even later than the atomic bomb; it must have required very advanced technology.

"Computers? Actually, a mobile phone is just a miniaturized computer!"

As Ma Hongwei spoke, a thought struck him, and he took out a monitor, a host, a keyboard, a mouse, and a power strip.

Of course, he didn't forget to remove the battery as well.

Without a battery, the computer cannot function.

Upon seeing the large display screen, Deputy Division Commander Xu nodded and said, "Yes, it does resemble a large mobile phone."

"In the earliest days, mobile phones could only make calls, not make video calls or access the internet."

As Ma Hongwei explained, he connected the power supply and pressed the power button: "Back then, the only way to access the internet was to use a computer, but with the development of technology, computers have become smaller and smaller."

"Technology is constantly advancing, and eventually, many functions on computers can be directly ported to mobile phones."

"However, a mobile phone is still just a mobile phone, and in many ways it is still not as powerful as a computer."

At this point, he looked at the leaders and said, "The reason I brought the computer with me this time is to use its powerful computing capabilities to help calculate the Japanese army's radio codes."

Commander Liu's expression turned serious as he inquired, "Comrade Hongwei, is it really possible to crack the Japanese army's field codes?"

Japan has many types of radio codes, and strictly adheres to the separation of the army and navy, diplomatic independence, and battlefield tiered use, none of which are universal.

The main enemy facing the Eighth Route Army was the Japanese army, so the Japanese army's field codes were their primary target for eavesdropping.

"It's very easy if it's simple. If it's top secret, it might require capturing the Japanese codebook."

Ma Hongwei didn't make any guarantees, but rather cautiously said, "This one computer alone can do the work of many people doing the calculations together."

He paused for a moment, then continued, "In addition, I also brought some books and materials published in later years about Japanese military codes during World War II. Some of these materials were from the Military Intelligence Bureau, some from the American imperialists, and some were deciphered by our Eighth Route Army's codebreakers."

As he spoke, Ma Hongwei casually waved his hand and took out some printed books and papers.

He pulled out a few sheets of paper and said to the group of leaders, "Gentlemen, look at this. It's the Japanese Army's code, divided into four levels: battlefield simplified, divisional field, high-level military intelligence, and logistics-specific."

"The mainstream cryptography of the Japanese army is a five-digit character set plus random number addition encryption (addition table encryption), which consists of two systems."

"The codebook contains tens of thousands of words, place names, and unit numbers, which are then encrypted twice by overlaying a random five-digit number table. The random number table will be replaced regularly during wartime."

"Simple field codes used at the grassroots level are used by squads and brigades. They consist of only three-digit short codes and single-label replacement codes. The frequency of replacement is low, and such simple codes are the easiest to crack."

Ma Hongwei recalled that in 39, the Second Bureau of the Military Commission cracked this rudimentary field code and accurately located the position where Abe Norihide was trapped during the Battle of Huangtuling, killing the Japanese lieutenant general.

"The main code used by the Japanese divisions was a seven-digit encryption system used by regiments and divisions."

Ma Hongwei continued, "This kind of code is a fixed codebook. The addition random number table is changed every 10 to 30 days. Before each sweep or encirclement operation by the Japanese army, the key would be changed temporarily."

"That being said, as long as we grasp the pattern, we can determine and predict the timing of the Japanese sweep by observing the changes in the code."

"The most difficult one is the Japanese Army's high-level military secret code. This is a code that can only be used by the front-level army. It has a special mechanical rotary encryption machine and is a simplified version of Enigma. The key is changed every week."

"At this stage, our main enemy is still the Japanese army in North China, not all of the Japanese army. Therefore, we can prioritize cracking the basic field codes at the grassroots level, as well as the 'seven codes' of the main forces at the regimental and divisional levels."

Pointing to the contents of the paper, Ma Hongwei continued, "According to the information summarized in the book, the passwords are strictly hierarchical and will never be mixed. Only during sweeping operations will the front-line troops temporarily use wartime temporary keys, and they will switch back to the regular passwords after the war."

"When it's an emergency request for assistance or a call for artillery support at close range, they often take the easy way out and send the message directly using Japanese kana in plain text. This is when their intelligence is most easily intercepted."

"In addition, each of their regiments and independent battalions has its own radio call sign. We can accurately determine the organization and movement of Japanese troops by using the call sign and code words, but we can only find out after we decipher it."

Upon hearing Ma Hongwei's account, Political Commissar Luo said, "Comrade Hongwei, please help us purchase more Japanese language books when you get back. This will be beneficial for our comrades in monitoring Japanese radio broadcasts and deciphering codes."

"OK."

Ma Hongwei nodded and said, "I will buy it when I get back, and Weiwei will transport it over."

Then he said to the leaders, "Sirs, my main task here today is to teach some people how to use computers."

"On this computer, I have deployed local AI and Python scripts that can batch clean and segment ciphertext based on a large number of telegram samples and statistical code group patterns, extract duplicate fragments, process this data, and then use large models for reasoning to help cryptanalysts eliminate a large number of hypotheses and speed up the trial and error process."

"In this way, what used to be hundreds or thousands of tasks that required manual statistics and analysis can now be handled with just one computer."

"If you are skilled enough, it will only take a few weeks to crack some of the Japanese army's logistics and garrison radios, which have relatively weak security."

"As for the main force's codes, we still need to analyze the data captured on the battlefield to figure them out."

"While computers have powerful computing capabilities, they are not omnipotent."