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Questions tagged [enigma]

The Enigma Machine was a piece of cryptographic hardware used by the German military during World War II; successful cryptanalysis was routinely applied against it and the scheme was considered broken. Questions relating to this machine should use this tag and you may also which to use the historic tag.

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Question about Enigma's rotors turnover

I've been trying to make an algorithm work like the real Enigma machine, fully customizable. I use two online emulators to check that my encoded message is correct : https://cryptii.com/pipes/enigma-...
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31 votes
8 answers
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Have any cryptographic breaks been executed in the real world since World War II?

Have there been any publicly known exploits of a cryptographic break in a widely used cryptographic system to actually read encrypted information (or falsely authenticate) since the Ultra program in ...
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2 votes
1 answer
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Does machine cryptography only consist of rotor machines?

For the chronological categorisation of cryptography, I have proceeded as follows: Cryptography by hand (e.g. Caesar, Vigenére, etc., till around 1900/1920) Cryptography using machines (e.g. Enigma, ...
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Enigma machine rotor internal wiring question

I have a question regarding the internal wiring of the rotors of the Enigma machine. I'm trying to understand some details about the original Enigma machine. To the best of my understanding, each ...
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5 votes
1 answer
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What were Alan Turing and their team searching before doing KPA in the movie "The imitation game"?

I just watched the movie "The imitation game" (2014) which is based on Alan Turing's biography. At some point in the movie the machine built by Turing wasn't fast enough to decrypt the ...
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2 answers
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Is a long Enigma message vulnerable to the index of coincidence?

Let's say we have a ciphertext of length 1000. We try to decipher it with an Enigma machine with random rotors and initial positions but no plugboard (so only $5 * 4 * 3 * 26^3 \approx 2^{20}$ ...
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3 votes
1 answer
170 views

Enigma machine Encryption steps

I am trying to build a simulated enigma machine.I am basing it off of this one https://www.101computing.net/enigma-machine-emulator/ I have setup the 3 rotors and I am having trouble understanding the ...
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How many possible settings with enigma machine? [duplicate]

I am currently writing an assignment about the Enigma machine, and im wondering how it makes sense that the highest possible ammount of settings is 158,962,555,217,826,360,000, with 10 wires plugged ...
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1 answer
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Is my Enigma inspired cipher any good?

I am working is a project that would implement a cipher that would output ciphertext that would be easy to transmit through morse code, just like they did in the days of Enigma. Use of AES or the ...
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Enigma Machine rotors math

I have been doing a study about the enigma machine for the past weeks. I managed to get ahold of the formulae used in "Cryptography, Information theory and error-correction" book for the ...
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2 votes
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Why are there only 10 plugboard pairs in the enigma?

The plugboard provides a new layer of security for the enigma but why can we only swap at most 10 letters? I only found things like "10 was the most common." but why stop there? Isn't adding ...
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1 vote
1 answer
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Enigma ring settings - is the relative location of the turnover all that matters?

I understand that the ring setting of an Enigma rotor changes the alignment between the internal wiring and the letters on the ring. For example, in the diagram below, rotor I has ring setting 2 (B), ...
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Looking for books and non-paywalled websites about Enigma "rapid analytic machinery"

I am by now perfectly aware that "Bletchley Park had much more available to them than 'Bombes,'" but I'm finding it difficult to find on-line explanations of their many other types of "...
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1 vote
1 answer
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Enigma - How many possibilities does the plugboard have?

I try to relate my own calculation with the real result being about 150.738.274.937.250. The plugboard has 26 letters, and you have 10 wires to connect pairs of letters. My idea was to calculate first ...
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2 votes
1 answer
166 views

Explanation of Enigma rotor movement

I found this explanation of Enigma rotor movement on this website, but can't quite understand the methodology: Enigma rotation example A ⤑ B → D ⤑ C (rotor III in position B) C ⤑ C → D ⤑ D (rotor II ...
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7 votes
1 answer
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Why does the Bombe not consider the Ringstellung when determining stecker pairs?

I am doing research on the Bombe Machine, and I read that when the Bombe tries to find the stecker (plugboard) partners of letters, it only needs to use the rotor types and arrangement and also the "...
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4 votes
1 answer
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Why are the indicator drums of a Bombe machine labelled from A to Z clockwise?

I am researching the Bombe Machine, having just completed a project on the Enigma Machine. I visited The Rutherford Journal - The Turing Bombe, and it claimed that The scales on the three ...
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What was the key length of the Enigma? [closed]

When I type in any plaintext to an Enigma machine (Enigma machine emulator) the substitution does not seem to follow any pattern. In other words, there is no cycle in the use of enciphering alphabets (...
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1 vote
1 answer
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Secure enigma machine?

The enigma machine had a serious flaw: the letters could not be encrypted as themselves. Is there an online enigma simulator I can try that does not have this flaw, which would likely make it secure?
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2 votes
0 answers
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How does a ring affect an inverse rotor?

Rotor I with ring A would look like this: ABCDEFGHIJKLMNOPQRSTUVWXYZ ↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓↓ EKMFLGDQVZNTOWYHXUSPAIBRCJ Inverse rotor I with ring A would look ...
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2 votes
1 answer
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What's different between ground setting and ring set in the Enigma machine?

I am writing a python program for the Enigma machine. I know what the ground setting (Grundstellung) is but I don't know the difference between ground setting and ring setting. What's different ...
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What is the best way to attack enigma without any a priori knowledge about the plaintext?

I know in great (great great great) detail about how they cracked enigma during the second world war. Looking into it, I decided to have a crack at breaking it. I've come apon a single problem with my ...
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1 answer
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How much would removing enigmas biggest flaw improve it?

Enigma's biggest flaw was that a letter could never be encrypted as itself. How much would enigma's security increase if it were possible that a letter could be encrypted as itself? I know that would ...
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2 votes
3 answers
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Was Enigma really that hard to crack, given that you had access to hundreds of messages per network per day?

Well, I guess that I have always been a little bit suspicious ... so to speak ... of the "official stories" about the difficulty of recovering Enigma message texts during WW2, because it seems to me ...
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3 votes
1 answer
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Theory Question with Enigma

I have been reading a bit about how the Enigma machine was cracked in WW2. There was also this wonderful post which highlighted a lot of useful information. Let's assume I know everything about how ...
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1 answer
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Question about Enigmas involutional property and its reduction of possible ciphers

I'm currently learning cryptography at a university. I can't wrap my mind around how the involutional property of Engima reduces its possible ciphers while being poly-alphabetic. Can someone please ...
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3 votes
1 answer
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Enigma message decode errors, and protocols to prevent them

I was looking at some Enigma messages for some random reasons, and I wondered if there were ever issue pulling the correct words out the strings of characters of if there was a protocol for it. For ...
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3 votes
1 answer
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How can the Enigma's plugboard settings be found with partially known plaintext?

I don't quite understand the procedure described on wikipedia, is there a generalized procedure you can follow to rule out a pairing on the plugboard? For example, let's say the cipher text is ...
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2 answers
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Was the Enigma's double stepping mechanism intentional?

It's sometimes refered to as the double stepping anomaly, so was it just a design flaw or was it put in place deliberately?
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1 answer
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Enigma rotation example

According to wikipedia: BDZGO is the expected outcome when doing the enigma chipher on the letters AAAAA with rotors I,II,III and reflector B. ...
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19 votes
4 answers
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Are encryption algorithms with fixed-point free permutations inherently flawed?

Flaw in Enigma One of the Enigma machine's flaw was the derangement (fixed-point free permutation) of the produced ciphertext, or simply put: No plaintext-letter can be enciphered to itself. See this ...
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2 votes
3 answers
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Enigma: a Question from WW2

I have seen in the Imitation Game that the Germans reset the Enigma at midnight sharp, and then they start messaging by sending the weather report in the morning. But the device made by Alan Turing, ...
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3 votes
0 answers
158 views

Fastest / easiest way to find rotor wiring without physical inspection on Enigma Machine emulator

We have an Enigma machine emulator we are trying to replicate. Machine has 3 rotor positions and 6 rotors that can be selected. The input goes through 3 rotors then is reflected back to start as is ...
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0 votes
1 answer
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How to decrypt / break enigma-encrypted ciphertext with given configuraton?

I'm new here--seriously I don't know anything, but my close friend sending me a code and I must solve it. The code uses Rotor III, V, VIII; starting point ABC; reflector BB; and pair OA LU. Can ...
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1 answer
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Enigma: Theorie Rotors [closed]

I wanted to programm the enigma (using C#). But it seems like i dont understand how the rotors work. Becouse if we take the first three rotors: ekmflgdqvzntowyhxuspaibrcj ajdksiruxblhwtmcqgznpyfvoe ...
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3 votes
3 answers
371 views

Rotor machines: secrecy of the wiring

During the heyday of rotor machines, the internal rotor wiring was always a closely guarded secret. Even fully cleared repair staff was not allowed to do anything that could reveal it. As the wiring ...
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6 votes
2 answers
1k views

When does the first rotor in Enigma machine rotate?

I read a ton of articles about the Enigma machine. And the one thing that I can't get is when the first rotor stars rotating. Some articles says the rotor rotates after the first letter of message ...
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1 vote
2 answers
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Using enigma and missing one word/sentence

After you set up all rotors, position and plugs in Enigma machine. If you don´t get the signal of one word or one sentence... your enigma settings are desynchronized. How you can recover from this ...
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4 votes
4 answers
874 views

Modifying an Enigma machine to allow unchanged letters

One of the biggest flaws of Enigma was that a letter couldn’t represent itself because the route through the machine was one-way. I was thinking a quick fix could be to introduce a rotor position that ...
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2 votes
1 answer
184 views

What is the difference in exchanging the Enigma rotors in their slots?

I have a question regarding the exchange of the rotors in a enigma machine. I know that there are 3 slots and that up to 8 rotors can be used in those slots. What I don't understand is, as all the ...
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1 vote
1 answer
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Order of letters on 3-rd rotor: Enigma III

In the photo you can see the three Enigma's rotors. On the 1-st rotor (marked with number 50 on the photo) letters put on clockwise. On the 2-nd rotor letters put on counterclockwise. Question. ...
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3 votes
1 answer
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Is it right that the Bomba can halt, but give you a different settings other than the one Germans really used for encryption using an Enigma?

Considering different groundsettings for these messages: AWE RDE AFR AFG HIU HKQ (where similar letters were known as (1,4) ,(2,5) females etc. I think the cipher clerk rotated the rotors based on ...
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2 votes
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Why the permutation of the right hand rotor given in Rejewski's paper is $PNP^{-1}$?

I would like to know why the permutation of the right hand rotor given in Rejewski's paper is $PNP^{-1}$. First of all I can't get how he added an $P$(alphabetic permutation) at the front of $N$(...
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3 votes
1 answer
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Why Rejewski advanced three position for the right rotor in the second set of rotors in the Cyclometer he devised?

In this article about decryption of Enigma(p.259), author says that the second set of rotors was stepped three positions beyond the groundsetting in the Cyclometer Rejewski devised. I would like ...
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2 answers
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How to calculate the key size of a redesign of Enigma

I have a 'for fun' project, which is a pure software based redesign of the Enigma I. I'd like to compute the key length of my design, but I need some help with that. I have a write-up here (see ...
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2 answers
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Key vs Algorithm when applied to Enigma

I've just been reading the Why should I make my cipher public? question and answers on this site. I understand Kerckhoffs's principle, but I'm unsure exactly how this applies to Enigma - i.e. where ...
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3 votes
2 answers
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A Modernized Enigma?

I've seen answers here and elsewhere discussing how well the WWII Enigma could hold up to modern cryptanalysis, however, those answers always seem to assume the WWII conditions where the Germans had a ...
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6 votes
1 answer
605 views

Does adding more characters to the Enigma rotors improve crypto strength?

This seems like an obvious question but I haven't been able to find it, so here goes: Enigma is based on an alphabet of A-Z (26 characters); obviously this directly affects message content (e.g. ...
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7 votes
0 answers
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culling equivalent Enigma keys for short messages [closed]

The following for-loop iterates over all possible keys for an M3 Enigma for three selected rotors: ...
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1 vote
0 answers
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Possible enigma settings? [duplicate]

I'm writing an assignment about the Enigma machine, and i'm trying to calculate the amount of settings the enigma machine has. I have found several sites regarding this topic, but it seems like there ...
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