Iron Sonata of World War II

However, Helena ultimately insisted on using higher steam parameters for two reasons:

One is that for a destroyer that relies on speed for food, the first goal pursued by its power system is light weight, small size, and high power. In contrast, reliability and thermal efficiency can be sacrificed to a certain extent.And this is also a common practice in various countries. Anyway, destroyers do not have such high requirements for long-term overseas deployment.For the Germans, there is no need for destroyers to be deployed overseas, and the ultimate output of the power system is king!

The second is that Helena hopes to completely solve the reliability problem of the German high-temperature and high-pressure boiler power system through running-in on the destroyer in the next few years.After all, although there were certain problems with the reliability of the power system of the German warships in the previous plane, the root cause of this result was the generational gap in the application of the power system of the German warships, which caused the Germans to directly merge the power systems without sufficient verification. Immature high-temperature and high-pressure boilers are used on battleships.

In addition to the improvement of the power plant, the new destroyer has also made some efforts to improve the protection capability.At this time, some people may be surprised: what?Aren't destroyers all streaking?How come there is still protection?

In this regard, Helena said that it is impossible for a destroyer to withstand large and medium-caliber shells. It is tantamount to putting medieval heavy cavalry armor on an assassin who is good at flying over eaves and walls.But this does not mean that destroyers should give up healing in terms of protection. After all, destroyers face a variety of threats, not just direct hits from opponent shells or bombs.For destroyers during World War II, direct hits from shells, bombs, and torpedoes are certainly terrifying, but another type of threat cannot be ignored.There are three main types of threats: one is fragments, the other is shock waves, and the third is aviation cannons.

Fragments and shock waves are not difficult to understand. Even if shells or aerial bombs do not directly hit the hull, but explode in the water close to the hull, the shrapnel and shock waves produced by them are not a small threat. The shrapnel can penetrate thin steel plates, and the shock waves Then the hull with insufficient strength can be torn apart.

The most confusing thing for the audience here is probably the aviation machine gun. Is it difficult for the small-caliber aviation machine gun to threaten the ship?In fact, this thing really can not help but guard against.In World War II on the previous plane, it was a very common tactic for fighter jets and dive bombers to straf enemy warships with cannons while attacking.For large warships, strafing cannons can destroy surface equipment and kill exposed personnel; for small unarmored destroyers, strafing cannons can easily penetrate its waterline hull, which is only a few millimeters thick, and aggravate its attack. water.In the Pacific War on the previous plane, it is said that the reason why Japan's fastest destroyer "Shimakaze" sank was that the waterline was pierced into a hornet's nest by the 12.7mm machine gun on the American plane, and the cold sea water poured into the cabin and the already overheated ship. The boiler came in close contact... Then the boiler of the "Shimakaze" blew up, and then there was no more (the 12.7mm heirloom of the Bald Eagle can also be used to fight ships).

For these three types of threats, Helena's solution is to provide destroyers with strong hulls and protective longitudinal walls.In the entire power compartment, the new destroyer uses nickel-chromium steel plates with a thickness of 20mm on the side and a thickness of 15mm on the deck to build the hull. Behind the side hull is the oil tank of the destroyer, and a 15mm thick waterproof longitudinal wall is added behind the oil tank. Connected with the double bottom, the main turret and part of the bridge of the new ship are also protected by 20mm armor.Among them, the hull with 20mm on the side and 15mm on the deck, as well as the armor of the turret and bridge can resist the fragments of near-missing bullets, and can withstand the strafing of aircraft guns below 20mm. The oil tank and protective longitudinal walls can absorb near-missing shock waves. .

Since the hull and protective longitudinal walls are part of the load-bearing structure of the hull, Helena's design will not cause too much burden on the displacement of the battleship, but can also increase the longitudinal strength of the hull by the way. The North Sea is particularly important.

Chapter 66 Superalloys

After some hard work by Helena and the designers, after a few months, a 2750-ton large destroyer with a flying shear bow, long forecastle, and double funnels finally stepped off the drawing board and officially started construction.The start of the construction of this type of destroyer marks that the last warship built by Germany within the share allowed by the "Washington Treaty" is on the berth. German ship designers can finally usher in a period of leisure for a while. By the way, summarize the past A phase of design experience too.

The work of the ship designers has temporarily come to an end, but Helena is still continuing her great career of developing the technology tree and enjoying it.After Helena's continuous investment for many years, it is finally time for the German superalloy research and development project to see results.

Superalloys, as the name suggests, refer to a class of alloy materials that can work in high temperature environments for a long time.Although some high-temperature-resistant metal materials were used in the superheater and turbocharger of the booster boiler in Germany before, the temperature in these occasions is basically below 500 degrees Celsius, and the working environment of the parts is not very harsh, so the development The difficulty is not too great.

However, Helena couldn't be satisfied with the existing alloy materials.In Helena's plan, whether it is the exhaust gas turbine of an internal combustion engine, the gas turbine pump of a rocket engine, or the hot-end parts of a jet engine, their working temperature is at least 600 degrees Celsius, and some can even reach 800 degrees Celsius. Left and right, the existing materials are definitely not up to the task.Therefore, Helena has not stopped investing in the research and development of high-temperature alloys for a moment in these years.

In the eyes of many people, it is an irrefutable truth that competition brings technological progress.But Helena thinks that this sentence actually has a scope of application.For an industry that has entered practical application and is in a stage of steady development, the saying that competition brings progress is very correct.However, for the technical fields that have just started and are still in the pioneering era, due to the lack of traction by market forces, it is often necessary to rely on the power of the state to maximize the concentration of scientific research resources in order to achieve technological breakthroughs at the fastest speed.

Now the research on high-temperature alloys in various countries is obviously still in its infancy. In order to concentrate resources to achieve technological breakthroughs, Helena did not ask the design teams of each company to come up with a set of plans like the previous engine bidding, but with the "Peace Fund" For traction, major metallurgical industrial enterprises and relevant research institutes in Germany are required to set up a joint research team to jointly participate in the development of a new generation of superalloys.

According to the main components, superalloys can be divided into iron-based superalloys, nickel-based superalloys and cobalt-based superalloys.Due to the high price of cobalt and the small reserves on land, considering that it was difficult for Germany to obtain large-scale cobalt ore from the outside world during the war, Helena decided to focus on the development of iron-based superalloys and nickel-based superalloys.After several years of trial and error (in fact, if Helena hadn't kept insinuating to the technicians during this period, the development cycle would have been longer), the development of iron-based superalloys was the first to succeed, which is a nickel containing about 10%, containing about 20% chromium, and about 3% aluminum, the highest service temperature can reach 780 degrees Celsius.

This achievement can be said to be very exciting for Helena.On the one hand, the cost of this kind of alloy is relatively low, and the consumption of rare metals is not too large; The rocket gas turbine pump is also perfectly fine.

The only thing that makes Helena regret is that if this alloy is to be used as the hot-end blade of a jet engine, it is a bit reluctant.You must know that in the previous plane, the temperature of the vortex front of the German ME262 jet fighter engine was as high as 771 degrees Celsius, which is already very close to the use limit of this iron-based superalloy, which will greatly reduce the service life of the hot-end parts of the engine, and It will make it difficult to further increase the engine thrust.Although this problem can be solved by machining channels inside the turbine blades and using cooling air to cool the blades (convective cooling), this will also greatly increase the difficulty of processing and production costs.

Regrets are regrets, Helena also clearly knows that compared with nickel-based superalloys, iron-based superalloys have a lower technical threshold and are cheaper in price, but their development potential is really not great.According to Helena's experience in her previous life, the limit working temperature of iron-based superalloys is around 800 degrees Celsius, so even if Helena has the metallurgical knowledge of later generations in her mind, there is no way to change the fact that iron-based superalloys are close to the performance ceiling .

So want to get stronger?Then hurry up and krypton gold!In order to break through the performance ceiling of iron-based superalloys, Helena asked the R&D team to develop nickel-based superalloys with better performance, and significant progress has been made in the laboratory.The performance of this nickel-based superalloy is very superior, its maximum working temperature reaches 980 degrees Celsius, and it can be extruded and forged as a deformed alloy, and can be cast as a casting alloy.

The main component of this nickel-based superalloy is nickel, and it also contains 16.5%-19.5% chromium, 13.5%-16% cobalt, 4.5%-5.5% titanium, 2.5%-3.5% molybdenum, 2%-3 % aluminum, 1%-2% tungsten, and a small amount of lanthanide rare earth element cerium.In fact, this ratio is roughly the ratio of the famous GH4710 alloy in later generations. Of course, the specific production process is all perfected bit by bit by German metallurgical experts in countless failures. After all, a new type of alloy is to be developed. , just knowing the ratio of its chemical composition is far from enough, and the poor metallurgical knowledge in Helena's brain is basically fragmented.

However, Helena relied on her timeless talk to shake out these fragments of knowledge, which still greatly accelerated the development process, and by the way made a group of metallurgical experts admire them all. Helena blushed a little.

Helena is very satisfied with the progress of the development of superalloys. The development of nickel-based superalloys has made Germany far ahead on this track. In the early days of the cold war on the plane, they did not lag behind.The only problem now is that if war breaks out, Germany's rare metal reserves don't know whether it can still afford such krypton gold materials.

Therefore, for the development of high-temperature alloys in Germany in the future, Helena's basic plan is to walk on two legs: the supercharged turbine of the internal combustion engine and the turbo pump of the rocket engine with a lower working temperature use iron-based high-temperature alloys that are cheap and consume less rare metals. alloy.As for jet engines with higher operating temperatures, it depends on the situation. If there are enough rare metals at that time, nickel-based superalloys will be used. If there are not enough, iron-based superalloys will be used. Anyway, the temperature before the vortex of the first-generation jet engines is also high. not going anywhere.

Chapter 67 The Puzzle

Recently, Professor Bohr of the University of Göttingen suddenly received a large amount of research funding from the "Peace Fund" for the research on the subject of "the process of heat conversion into gas flow energy", which made Professor Bohr feel flattered.Of course, this was Helena's handwriting again, but what Professor Pohl didn't know was that Helena didn't value him, but his proud student—Hans von Olympian, who was studying for a Ph.D. in physics. because.Hans von Ohain, the future aviation master, had already conceived a great idea at this time, the ultimate goal of which was to design an engine powered by gas injection. research group.

In the last plane of history, Dr. O’Haiyin successfully tested the first human jet engine Hes-1937 on the ground in March 3, and in 1 he will send the first human jet engine He-1939 to On the blue sky.However, at that time, many high-level Air Force leaders headed by Goering were not interested in the He-178 at the beginning, because at this time the He-178 had not yet shown a clear speed advantage over the propeller aircraft, and the jet aircraft stayed in the air for a short time and failed. However, the problem of high production rate was more prominent, and the development of German jet aircraft was slowed down for a time, until Germany suffered setbacks on the battlefield.Only then did the top brass of the German Air Force remember to pull out the life-saving straw of the jet aircraft. This is the He-178 and Me-280 that everyone is familiar with.

When Germany was defeated in 1945, the U.S. Navy took the lead, and immediately "hijacked" Dr. O'Hain very politely.Unexpectedly, before the U.S. Navy put Dr. O'Hain in its hands, the U.S. Air Force was established in 1947.

After the establishment of the U.S. Air Force, apart from anything else, the first thing to do was to snatch Dr. O'Hain from the mouth of the U.S. Navy, and then provide it with delicious food and drink, and sent it to the very famous "propulsion laboratory" in later generations.O'Hain later became the chief scientist of the Propulsion Laboratory and worked there until his retirement in 1979.

During his work in the "Propulsion Laboratory", Dr. O'Hane not only helped the United States establish its position as the world's aero-engine hegemony, but also cultivated a large number of outstanding talents for the U.S. aero-engine industry. For example, under the guidance of Dr. O'Hane , his disciple Paul Beveracqua further invented the "lift fan", and it was this "lift fan" that later developed into the front fan of the F-35B vertical take-off and landing fighter.

It is precisely because of the extraordinary achievements of O'Hain in the previous plane, that Helena, who has always been keen on nurturing big cows, couldn't help showing a gratified aunt smile after hearing that O'Hain joined the research group.

Since it is only 1932 now, even with Helena's vigorous promotion, jet engines are still in the early stage of technological exploration, and it will be impossible to see practical products in a short while, so Helena is not in a hurry.But another matter has come to a time when it has to be solved, and this problem that needs to be solved is the confidentiality system of the Enigma cipher machine based on the Germans.

Since ancient times, the value of intelligence to war is self-evident. In order to prevent its own telegrams from being intercepted by opponents and causing intelligence leakage, Germany adopted an advanced mechanical encryption system called "Enigma".

The magic of this kind of encryption machine is that through this kind of cipher machine, a well-written message can be converted into a seemingly random sequence of letters and sent, and the receiver only needs to have the same cipher machine as the sender , you can restore this irregular sequence of letters to a well-written telegram.In this way, even if the enemy intercepts our radio signal, all they get is a string of irregular letters.

In the early days of World War II on the last plane, the German army once relied on the "Enigma" cipher machine to keep its military intelligence extremely confidential, laying a solid foundation for the success of the Blitzkrieg.However, at the end of the war, the "Enigma" cipher system was successfully cracked by the opponent and turned into a broken house with leaks everywhere, which brought greater strategic passiveness to the German army, which was already in trouble, and accelerated the development of the Third Reich. of defeat.

So why did the cipher system based on the "Enigma" cipher machine be unbreakable at first, and then become full of loopholes later?This starts with the principle of the "Enigma" cipher machine.

The specific structure of the "Enigma" cipher machine is relatively complicated. Let's make a long story short. The reason why the sender of "Enigma" can turn the message into an almost irregular sequence of letters, and the receiver can restore the sequence of letters to The telegram mainly relies on three core components, which are: rotor, wiring board and reflector.

Let’s talk about the rotor first. The “Enigma” cipher machine has three to five rotors in total. Each rotor has two sides, and each side has 26 contacts (representing 26 German letters). There are a series of wires inside the rotor to connect The contacts on both sides are connected in pairs, so that when the current flows from the contacts on one side of the rotor to the contacts on the other side, the typed letter is replaced by another letter.

If it's just such a simple replacement, the password is of course easy to decipher. The ingenuity of the "Enigma" cipher machine is that it has multiple rotors (usually three rotors, but also four or five rotors, three rotors will be used as an example below), and each of these rotors has The connection methods of the wires are different. When the contacts on the adjacent sides of each rotor touch, the circuit between the two rotors is connected.As current flows through these rotors in sequence, the typed letters are replaced multiple times.

The rotor of the "Enigma" cipher machine is equipped with an anti-reversal tooth and anti-reversal claw system, which allows the user to toggle the first rotor to rotate 1/26 of a circle every time a letter is input, and when the first rotor ( When the fast rotor) turns to a certain point, the second rotor (middle rotor) will also be driven, and when the second rotor turns to a certain point, the third rotor (slow rotor) will also be driven... This makes Every time the user enters a letter, the circuit between the three rotors will change once, which is the so-called "duplex replacement".

The double replacement makes the input letter and the output letter no longer a simple one-to-one correspondence, which greatly increases the difficulty of cracking. The different directions of the three rotors can produce 26×26×26=17576 circuit combinations.Moreover, the three rotors of the "Enigma" machine can also replace each other's seats, so there are more combinations.

After talking about the rotor, let's talk about the wiring board, which is another safety measure of the "Enigma" machine.Each wire on the terminal block is connected to a pair of letters.The purpose of these wires is to change the direction of the current before it flows into the rotor.For example, we connect the A jack to the E jack.When the operator presses the A key, the current will first flow to the E socket and then flow into the rotor. Up to 13 wires can be connected to the terminal board at the same time.

Although the wiring board is only a one-to-one simple replacement of letters, since each letter may be replaced by other letters, the wiring board is also connected in a terrifying number of ways. Even if only six pairs of letters are exchanged two by two at a time, 100391791500 combinations.

The combination of the wiring board and the rotor makes the "Enigma" machine combine the advantages of "simple replacement" and "multiple replacement". Nygma" is almost impossible.

The reflector is the third core component of the "Enigma" cipher machine. Its function is to connect the current flowing through the three rotors to another contact of the third rotor, so that the current can be led back from another loop. Then connect to the monitor.

The function of the reflector is to make "encryption-decryption in phase".For example, when the sender inputs the letter "C", after the current flows through the wiring board and the rotor, it is reflected by the reflector through another loop and passes through the display, the light representing "X" on the display lights up, and the letter "C" It is encrypted into "X".At this time, if the receiving party has another "Enigma" cipher machine of the same model, and its wiring board and rotor settings are exactly the same as this one, then the receiving party inputs the encrypted letter "X", Then the light representing "C" on the display will light up, and "C" is exactly the content of the message required by the receiver.This is the magical function of the reflector, which makes the encryption process consistent with the decryption process, greatly improving the efficiency of sending and receiving.

Then in the previous plane, why was the seemingly impeccable password system broken by the Allies? Where is the biggest loophole of the "Enigma" cipher machine?How can these loopholes be remedied?This is exactly what Helena is thinking about right now.

Chapter 68 Closing the Gap

In the previous plane, many military fans relished the story that the British obtained the "Enigma" cipher machine and code book from the sunk German submarine to decipher the German code. In fact, the cipher machine The acquisition of the physical object and a part of the code book by the United Kingdom did speed up the process of the Allied forces in deciphering the code.

But in Helena's view, the main reason why the German "Enigma" code system was deciphered by the opponent is not here. The flaws in the design of the "Enigma" cipher machine itself and the loopholes in the use of the German army are the root causes of the code being deciphered, and the fact that the actual cipher machine and the code book are obtained by the opponent is just to make it easier for the opponent to find these. Flaws and loopholes.

Let us use the attack and defense of the city as a metaphor: the "Enigma" cipher system is like a city built by Germany, and the British engineers responsible for deciphering the code are like an army attacking the city.The leakage of the cipher machine and the code book is like letting the siege army know that a section of the west wall was cut corners during construction, so the siege army concentrated its efforts to attack the weak west wall, and finally wiped out the city. It was attacked.

Now let us ask, was this city broken only because the weak link in the western section of the city wall was known to the opponent?I think most people will understand that the cutting corners during the construction of the western section of the city wall is the main reason for the city's collapse, right?Because even if the weakness of the city wall is not revealed, the siege party can always test out the weak point of the city wall through repeated tentative sieges!The weakness of the city wall was revealed in advance, which only accelerated the process of the city being conquered.

Therefore, the safety of a city cannot be based on the fact that the wall structure is not known by the enemy, but must be based on the fact that even if the enemy knows the structure of the city wall, they cannot find a weak point that is easy to exploit!

The attack and defense of passwords is actually the same as the attack and defense of cities.The secrecy of a cryptographic system cannot only be established on the secrecy of the encryption mechanism itself, but must be established on the secrecy of key generation and distribution!In this way, even if the opponent accidentally obtains the complete cipher machine and cipher book, it is difficult to find a loophole that can be continuously exploited.Just like the 19th century Dutch linguist and cryptographer August Kerkhoff said: the security of the cryptographic mechanism does not depend on the secrecy of the algorithm, and the cryptographic system should be known to everyone as to the operation steps of the system , as long as the key is not compromised, it is still safe.

So now the question is, "Enigma" cipher machine obviously has hundreds of billions of possible settings, and it uses a one-time pad encryption method, why is its key insecure?Below we will continue to illustrate this problem by analogy:

Many people have used suitcases with mechanical combination locks.Assuming that the user is a lazy person, he may use the same password every time (probably his own birthday or phone number), and then even if the password is changed, it is often only a few positions of the rotor of the combination lock. .We don't even need any professional knowledge of cryptography, just relying on intuition to know the potential risks of this password setting method.Because using the same password makes the password repeated, only turning the rotor a few steps destroys the uniformity of the probability distribution of the password.When the German army on the previous plane used the Enigma machine, many of the mistakes made were similar to those made by the lazy suitcase user above.

Specific errors include: sending the password twice for error correction each time (this was changed later), the password uses consecutive letters typed on the keyboard, and so on.The more serious problem is that the old-fashioned Germans send messages in a very standard format every time. They often explain the time, place, weather, people, and events in a fixed order... This is not counted, and many messages are coming to an end. Don't forget to give full play to the spirit of sending people's heads away from thousands of miles away, and add a superfluous "Heil Hitler!".

To solve this problem, Helena's solution is to introduce a pseudo-random number mechanism. The specific method is to first take a real random number as the "seed" (such as the current number of milliseconds), then multiply the "seed" by itself, and intercept the product The middle part is used as the next "seed", and then this process is repeated, so that a large number of pseudo-random numbers are obtained.

These pseudo-random numbers are used not only to specify the key, but also to specify the format of the text each time a message is sent through "Enigma".The specific method is to modularize all elements such as time, place, weather, people, and events, and then use a set of pseudo-random numbers to specify the order in which these modules are arranged.If necessary, some garbled characters can be inserted as modules between these useful element modules, or even between words. Since the human brain can easily distinguish useful information from garbled characters, this will not have much impact on the recipient's reading .In fact, the verification codes used by later generations to prevent machines from posting posts are also based on this principle, such as disrupting the order of an idiom and adding some noise around it for you to recognize.The essence of the verification code is to rely on the inductive ability of the human brain to irregular things to defeat the computing power of the computer.

The biggest advantage of relying on pseudo-random numbers to set passwords and writing order is to eliminate the path dependence and behavioral inertia formed by human beings in long-term repetitive work.The randomness of the password and the order of the text is completely entrusted to the ruthless mathematical model to execute.However, there is a difference between pseudo-random numbers and true random numbers after all. After the generated pseudo-random numbers reach a certain number, there will inevitably be repetitions (as long as the used seeds reappear, the cycle will start).Therefore, the original seed must be replaced or the pseudo-random number generation algorithm must be replaced after a period of time.

If the above problems are all human mistakes, the following problem is the defect of the "Enigma" cipher machine itself, that is, a letter can never be encrypted into itself.For example, "A" can be encrypted into any letter from "B" to "Z", but it cannot be encrypted into "A". A reflector of one of the large core elements.Because the reflector can allow the current to return from another arbitrary path, but it cannot make the current return from the original path.

One of the ways to solve this problem is to add a special rotor. The two sides of the rotor each have 78 contacts. Among these contacts, only any three contacts are connected with the contacts directly opposite it. The contacts are in contact with one electrode respectively, and the two electrodes are respectively connected with a key switch and an indicator light.When the button is not pressed, the rotor is also turned. In most of the time, the rotor has no effect, but as long as the contact connected by the wire and the opposite contact rotates to the electrode position, the current loop will be connected. , and the indicator light corresponding to the switch is on, and the letter is encrypted as itself.And the probability that any letter is encrypted as itself is exactly 1/26.

After Helena's above improvements, the security of the "Enigma" password system has increased by more than an order of magnitude, but Helena really dare not guarantee whether it cannot be cracked under the conditions of World War II.After all, the "Enigma" encryption system still has some inherent defects that cannot be solved.

Chapter 69 Von Neumann

In the previous plane, before the outbreak of World War II, Poland had begun to use the fatal negligence of Germany to enter the key twice before entering the text to decipher some encrypted messages (the specific deciphering method will not be expanded), after the start of World War II , Poland handed over their research results to the UK.At the beginning, the United Kingdom also followed the old method of the Poles, using the loopholes in the Germans' human nature to support the deciphering of "Enigma". Upgrading, this approach has become increasingly difficult to work.It was the famous mathematician and logician Alan Turing who really made the Allied Forces see the light from their predicament. Turing provided a brand new way of thinking for the deciphering of codes.

Turing found that similar words, phrases or short sentences often appear in similar places in German telegrams.For example, the phrase "Heil Hitler" (Long live Hitler) will be added to many telegrams. For example, the telegrams sent by radar posts far away from the combat zone often simply include the sentence "Keine besonderen Ereignisse" (Everything is normal). The word "wetter" (weather) often appears in telegrams...

Of course, just guessing the words, phrases, and phrases that may appear in the ciphertext is not enough to decipher the ciphertext. It is necessary to further determine the location of these words, phrases, and phrases.Fortunately, the telegrams sent by the old-fashioned Germans often follow a relatively fixed format. For example, "Heil Hitler" is usually placed at the end. When the Navy sends a telegram in the morning, it always reports the weather first, so the word "wetter" usually appears at the beginning of the message.This narrows the search range again.

Next, how to more accurately locate the ciphertexts that these words may correspond to?Turing discovered two weaknesses of Enigma: the first is that the aforementioned "Enigma" cannot encrypt a letter into itself, which is also the most fatal weakness; the second weakness is that when the sender When typing the same letter twice in a row, the result of the two encryptions will not be the same letter.

Knowing these two weaknesses, you can bring those hypothetical words, phrases and short sentences into the areas that may appear in the ciphertext, and move and compare them one by one. If there is something that does not meet the above two rules, you can Exclude this location.After narrowing down the possible scope again in this way, it is possible to roughly determine which letters these words, phrases and short sentences may correspond to.

After finding the possible correspondence, the number of possibilities of "Enigma" has dropped from the level of trillions to the level of millions, and then Turing can use his improved one called "Enigma" These possible correspondences are run on the computer of "bomb" (the specific process is more complicated, so I won't go into details), so as to finally decipher the "Enigma" code.

Knowing the general process of deciphering "Enigma" in England in the previous plane, the goal of Helena's improvement measures for "Enigma" is also very clear, that is, to do everything possible to prevent opponents from guessing and gaining Possible correspondence between plaintext and ciphertext.For example, the random number is used to determine the order of the elements in the text to prevent the opponent from guessing the approximate position of the possible plaintext in the ciphertext. For example, to allow the typed letters to be encrypted into itself is to prevent the opponent from comparing the plaintext and the ciphertext. method to exclude impossible positions.

In order to prevent the rule that the encrypted result will not be the same letter when the same letter is typed twice in a row is exploited by the opponent, Helena even further requires that the more common words with two consecutive letters must be gradually replaced in the text words. Words with the same letter, such as "wetter" (weather), are replaced by less distinctive words.

Helena believes that the above measures should still be very effective in countering Turing's "bomber", and these measures have little impact on the convenience of communication.Relying on random numbers to determine the order of keys and text seems to be troublesome on the surface, but in fact all random arrays can be prefabricated into a small box of marbles and distributed to the telegraph operator. The telegraph operator only needs to shake it before sending the message. Then just draw lots from inside.

In addition to the "Enigma" encryption system, Helena also organized the exploration and research of other types of encryption systems, mainly including the asymmetric encryption system based on large prime factorization, and the encryption system based on rare languages etc.

However, these encryption systems have certain limitations in this era. For example, the key of an asymmetric encryption system that relies on large prime factorization is too long. Another example is that relying on rare language encryption requires special encryption that is proficient in this rare language. and decoders etc.This makes the encryption process and decryption process very troublesome, so Helena is only planning to use these encryption methods as a supplement to the "Enigma" cryptographic system to improve the confidentiality of communication between important nodes.

……

In May 1932, Johann von Neumann, who had just been promoted to professor of mathematics at the University of Hamburg, was in high spirits recently.He was only 5 years old this year. This young professor, who is less than 28 years old, walked vigorously on the boulevards of the University of Hamburg, making it difficult to distinguish him from a group of students who are not much younger than him at the first time. .

Von Neumann, who just arrived at the University of Hamburg three years ago, was just a small guest lecturer. Although von Neumann believed that his talent was no less than anyone else, the competition for professor positions in German universities is extremely fierce today. It is an indisputable fact.According to von Neumann's calculations at the time, there will only be three vacancies for professorships in his major in the next three years, but there are more than 40 lecturers competing for these three positions!So much so that von Neumann was a little bit discouraged at the time. He even planned to try his luck at Princeton University in the United States, which is known for its eclectic recruitment of talents, if there is no hope of promotion within a year.

But the following things obviously exceeded von Neumann's most optimistic expectations, and everything went smoothly and unbelievably!In just three years, von Neumann was promoted from a guest lecturer to a full professor, and the University of Hamburg also solved his housing and nationality issues, which made von Neumann a little flattered.

Von Neumann believed that the reason why he was able to be reused by the University of Hamburg was largely due to the enthusiastic recommendation letter from his mentor, David Hilbert, from Göttingen.After all, Hilbert is the leader of mathematics in the world today, the leader of the famous Göttingen School, and it seems normal for the University of Hamburg to pay more attention to the people recommended by Hilbert.Thinking of this, von Neumann was full of gratitude to his former teacher and boss.

Chapter 70 Steel Feet

Von Neumann was right. The reason why he was successfully promoted from a lecturer to a professor of mathematics at the University of Hamburg was that David Hilbert’s recommendation played a big role, but Helen was also behind this incident. Na's vigorous operation.

Like the previous plane, von Neumann, who was born in Hungary, came to Germany to study in 1926. He first worked as an assistant under David Hilbert, and later worked as a lecturer at the University of Berlin and the University of Hamburg.Although von Neumann had already begun to make his mark academically at this time, von Neumann, who was only in his 20s at this time, was indeed too young. Becoming a professor at the age of 30 is really not an easy task.

In order to let von Neumann stay in Germany, Helena also went to the University of Göttingen to find David Hilbert, hoping that he could write a letter of recommendation to the University of Hamburg to help him in his efforts to become a professor Von Neumann helped.After all, Helena is not a member of the academic circle, and her words may not be as effective as Hilbert, an academic leader in the field of mathematics in the world.It’s not that Helena didn’t think about using money and power to forcibly interfere in the selection of professors at the University of Hamburg, but it’s too ugly, and the proud von Neumann might regard this behavior as a huge Insulting, so Helena had no choice but to follow the path of curves.

David Hilbert also admired von Neumann very much, and readily agreed to Helena's request.With the recommendation of a master like Hilbert, coupled with the secret help of Helena, von Neumann finally became a professor as he wished, and by the way, he gave up his original Hungarian nationality and joined the German nationality.

You know, in the history of the last plane, von Neumann spent a few years at the University of Hamburg, thinking that he had little hope of being promoted in Germany, so he turned around and went to Princeton University in the United States, which is actually Thirsty for talents, after seeing von Neumann's talent, he hired von Neumann, who was only 1933 years old, as a professor at the Institute for Advanced Study in Princeton in 30.In the last plane, the departure of von Neumann was a great loss to the German mathematics community. In this plane, the University of Hamburg finally retained von Neumann, which made the great collector Helena let out a long breath of relief.

In this plane, because of the existence of Helena, von Neumann did not leave Germany, and Konrad Zuse will not be buried in obscurity. Loewe and Siemens have also maintained a very high level of research on electronic devices. High intensity, if Germany's computer technology is still not world-leading, then Helena said that she can cut the number and re-train earlier.

But now the two future great gods, von Neumann and Konrad Zuse, are still in the growth stage. Helena said that what she needs to do to the great gods now is to feed them quietly and observe quietly.This hobby of collecting great gods has almost become a kind of entertainment in Helena's busy life.

……

A few months ago, at a motorized army training ground in eastern Germany, officers and soldiers were conducting motorized drive-in training, and a dozen strange-looking tracked vehicles were slowly and wobbly driving on the undulating road.At this time, on a small hill on the edge of the training ground, two soldiers in uniforms of German Wehrmacht officers were standing side by side.Through binoculars, they watched the tracked vehicles, which resembled trucks in the upper half, navigate obstacles.

"How's the troops responding to the new RS-1 crawler tractors? Heinz," said Colonel Oswald Lutz, Inspector General of the Wehrmacht's motorized units.He put down the binoculars and looked at the person in the uniform of the lieutenant colonel beside him. The person in the uniform of the lieutenant colonel beside him was Heinz William Guderian, the chief of staff just appointed by Colonel Lutz.

It turned out that since the 20s, the German army established the Motorized Troop Supervision Department to centrally manage the army's automobile troops. In 20, Colonel Oswald Lutz served as the Inspector General of the Motorized Forces, and in October of the same year Guderian was appointed Chief of Staff.Lutz is not only Guderian's first Bole, but also Guderian's mentor.Many of Guderian's ideas for the future mechanized troops were perfected bit by bit during the exchanges and discussions with Lutz.

Faced with his boss's question, Guderian, who has always been quick to talk, hesitated for a few seconds this time before saying: "From the standpoint of our commander, the RS-1 is really a good car. It always Gets what you want where you want it on time and almost never drops the chain. But our drivers may not like it that much, I've heard drivers give the RS-1 a tinge Meaning nickname, called "Parkinson's patient".

"Oh? 'Parkinson'? That doesn't seem like a very good adjective, so why did our driver call it 'Parkinson'?" Colonel Lutz suddenly became curious and asked.

"Mainly because it is not fast when it starts, but the jitter is indeed a bit large." Guderian replied.

"How big is the shaking? Let me try it too." Oswald Lutz said as he walked down the hillside. Ten minutes later, Colonel Lutz came to an RS-10 crawler tractor in the training ground.Taking off the binoculars around his neck and handing them to the guard beside him, Colonel Lutz stepped into the almost open passenger cab of RS-1.

"Let's drive, drive around the training ground, let me try to see how this car has 'Parkinson'." Colonel Lutz ordered the driver standing in the car.The area of ​​the chariot training ground is very large, and a circle around the training ground is several kilometers long.

"Yes!" The driver climbed into the driver's seat of the RS-1, accompanied by a harsh sound of track friction, the RS-1 started, and after a puff of smoke was emitted from the exhaust pipe, the RS-1 crawler tractor started , and slowly drove to the distance.

Half an hour later, the tractor slowly returned to the starting point.Colonel Lutz, whose old bones were almost shaken to pieces, managed to climb down from the passenger seat. The first thing he said after getting out of the car was: "I finally know why this car is called Parkinson's. That's really apt."

Chapter 71 Planning Dad

Looking at all kinds of tracked vehicles during World War II, those majestic tanks, invincible tank destroyers and self-propelled artillery roaring to the sky all make military fans of later generations lick their fingers.In contrast, those "dads" who are mainly responsible for auxiliary tasks such as personnel and material transportation and heavy equipment traction are much less popular.

However, this does not affect the importance of this type of equipment in the armies of various countries. The principle of soldiers and horses moving ahead without food and grass is the same in ancient and modern times.In fact, in the process of planning the blueprint for the future equipment of the German Army, Helena paid no less attention to these "dads" than she did to main battle weapons such as tanks.

When it comes to the auxiliary vehicles of the German army in World War II in the last plane, the first thing everyone thinks of is those various half-track vehicles. After all, the title of "half-track madman" is not just talking.However, Helena is not going to repeat what the Germans did in the previous plane. Although the half-track vehicles in the upper plane contributed a lot to the success of the Blitz, Helena still insists that the Germans vigorously developed the half-track vehicles, and Not a cost-effective vehicle.

The essence of the half-track vehicle is actually an attempt to integrate wheeled vehicles and A product of the advantages of tracked vehicles.According to the expectations of the designers, the price of the half-track vehicle will be cheaper than that of the full-track vehicle, and its off-road performance will be better than that of the all-wheel vehicle. It is a design that can greatly improve the mobility of troops with less capital.However, most of these assumptions are wishful thinking of designers.

The reason why the German designers expected that the half-track vehicle could be made cheaper than the full-track vehicle was mainly because the designers thought that the half-track vehicle could steer only by the front wheels, which could save the troublesome steering of the full-track vehicle Mechanism design (if a tracked vehicle wants to turn, it must produce a speed difference between the tracks on both sides, unlike a wheeled vehicle, it only needs to deflect the front wheels).However, the ideal is very full, and the reality is very skinny.German designers soon discovered that it is no problem for a half-track vehicle to rely on the front wheels to steer on the road, but when it comes to off-road, the steering force generated by the front wheels is often insufficient, making the turning radius of the vehicle very large.So the designers had to bring back the tracked steering mechanism that was expected to be removed, so that there are two types of steering mechanisms on a tracked vehicle.On the contrary, the steering mechanism has become more complicated than before, and the so-called cost advantage will naturally disappear.

It is precisely because the half-track vehicle did not reach its original design intention at all, so with the maturity of the all-wheel drive wheeled vehicle technology in the late World War II, the half-track vehicle quickly fell out of favor among the armies of various countries after the end of World War II, and no longer Major military powers continue to develop and equip more than half tracked vehicles on a large scale.

Therefore, in Helena's view, instead of spending a lot of effort to develop a bunch of half-track vehicles that will soon become obsolete, it is better to invest these scientific research funds in the research and development of all-track and all-wheel drive wheeled vehicles.In fact, the evaluation of the sdkfz234 8×8 heavy-duty wheeled armored vehicle launched by Germany in the last plane at the end of the war was quite good. Its transmission and suspension systems already have the main features of later wheeled tanks. Click this thing out at once, and there must be nothing wrong with the half-track vehicle.Although Helena didn't think highly of the half-tracked vehicles of the Germans in the previous plane, Helena highly praised another auxiliary vehicle in Germany. This equipment was the RSO crawler tractor.