A four-digit number represents a chinese word, three rotors and a reflector that completely disables the decipherer — the complexity of coding the matter, far beyond most people's intuition。
Cable code close-link rules
In our standard code book, "002" corresponds to "0447" to "country". A set of four-digit numbers represents a chinese word or a short sentence, with no gaps between all characters and close links. This is completely different from the habit of a series of words per english telegram and a series of four numbers per chinese telegram, which is read as a long stream of constant numbers。
This code was widely used in chinese telegraph communications from the end of the nineteenth century to the beginning of the twentieth century. The person who sent the telegram translated the entire passage verbatim into a series of consecutive numbers, sent through a wired or wireless channel, and the other person returned it to the original with the code book. The entire message was unstoppable, unseparated, and was a series of four-digit numbers immediately adjacent。
Morse code and serial waves
The core idea of morse code is to express the characters with a variable length signal: the short "show" is a point, the longer "show" is a row, the letters are made of points and a combination. This code can be transmitted by smooth, intermittent radio signals, usually called consecutive waves, abbreviated cw, which is the bottom language of the transatlantic service。
In 1997, the french navy officially shut down morse codes, and the last message said, "everyone, this is our last shout before forever silence." prior to that, american morse codes had been used in cable systems, which had operated for hundreds of years from rail to naval communications。
Enigma's three rotors
Enigma keyboards have 26 letters, which are essentially the same as modern computer keyboards, but remove spaces, numbers and markers. There are three rotors 6 cm in diameter above the monitor, hidden under the panel, which is the core of the entire machine. The first a key light bulb b was activated, the second a could become c and the third could be d。
The point is that every time you press a key, the rotor rotates and the letters change. The same annotation is replaced by a different letter in different places, and the same letter in a secret text may represent a different annotation. The traditional alphanumeric frequency analysis is completely ineffective here, which is the security advantage at the core of rotor design。
Reflector symmetrical encryption decryption
Shelbyus added a reflector at the end of the three rotors, connecting the keyboards with the same letters as the monitors. Press the a key signal to the d light bulb, and then press the d key signal in the opposite direction and eventually reach the a light bulb. The recipient simply transfers the rotor to the same initial direction, types it into a secret, and shows it automatically, and the same path is encrypted and declassified。
The reflector also has a side effect: one letter will never be encrypted into itself, because each letter in the reflector is always linked to another letter. In the 1930s, the sender agreed to use the initial direction of the three rotors as a key, typed it in order to record the alphabetical sequence of the light bulbs, then sent it by regular cable, and the other side returned with the same setup machine。
A combination explosion from rotors and connectors
The three rotors can be disassembled into a combination of 123, 132, 213, 231, 312, 321. The parties agree not only on the initial direction of each rotor, but also on the sort of arrangement. Connector panels can be plugged into a maximum of 10 links, allowing for a two-to-two exchange of the ten pair of letters, which alone produces 1003917791,500 possibilities。
These military-type machines and a small number of commercial-type sales vary in the rotor structure and the availability of commercial-type aircraft does not push the internal parameters of military aircraft. Even if the enemy were to intercept the whole secret, it would not be able to keep up with this combination by constantly spinning the secret key, which was the main reason why the german military had long relied on it in world war ii。
Virginia and the fence code
On the basis of a single caesarian code, people have extended the multiple "viginian" passwords to introduce the key concept. Select relations to be the key, specifying the first letter of the t-cipher, the initial letter r, and check in row r that the replacement letter of t is k, and so on. The two basic elements, the secret watch and the key, have been used since the second world war on the primary electronic password machine。
Another more modest approach is a fence password: a clear group of ns, which connects the first word of each group in turn, to form a seemingly irregular phrase. The recipient is aware of the reverse operation behind the n count of the fence. From telegraph code to rotor machine to fence, these methods set up a complete chain of password-based knowledge from manual to mechanical。
From 0022 to the rotor and then to the connector panel, each layer is designed to block the cracks left in the first layer. What do you think the first step would have been if someone had used that idea for encryption? The comment area would be welcome to talk and share it as useful as possible。
