3 votes

Under what conditions did a Bletchley bombe stop?

Suppose it is an Army Enigma I. Choose reflector UKW-B or UKW-C. Choose three rotors from I, II, III, IV and V. For each of the 120 reflector/rotors permutations, there are 17,576 starting indicator ...
Chan Tai Man's user avatar
3 votes

How to recover ring settings for the slow and the middle rotors on Enigma Checking Machine?

In this case there is simply not enough information to make a determination. The Ringstellung for the middle rotor only comes into play every 25x26=650 steps. A message of length 174 characters only ...
Daniel S's user avatar
  • 23.6k
3 votes

Enigma encryption

What you missed is that the signal goes through the plugboard twice. Quoting Wikipedia: Current flows from the battery (1) through a depressed bi-directional keyboard switch (2) to the plugboard (3). ...
Eugene Styer's user avatar
  • 1,676
2 votes

Why isn't my Enigma simulator working?

Rotors are I, II and III. Rings and indicator settings are at their home positions. Reflector is UKW-B. Suppose $E_0$ is an Enigma I machine without a plugboard; at $t=0$, $n_{\text{indicator}}=1$, i....
Chan Tai Man's user avatar
2 votes

Why isn't my Enigma simulator working?

Looks like you've misunderstood what happens to the permutation implemented by a rotor when it rotates. If a rotor which does permutation $\pi$ rotates through one step, the permutation it implements ...
Matthew Towers's user avatar
2 votes

Enigma encryption

Short answer: Enigma, with or without a plugboard, is self-inverse and never encode to itself. If $\mathtt{A}$ maps to $\mathtt{W}$, for the same machine state $\mathtt{W}$ maps to $\mathtt{A}$. ...
Chan Tai Man's user avatar
2 votes

Enigma encryption

Here is a partial Enigma schematic showing only 4 keys and light-bulbs, and 6 contacts per reflector (UKW), rotor side, and plug-board (Stecker) side (out of 26 due to space limitation). Simplified ...
fgrieu's user avatar
  • 141k
2 votes

How much would removing enigmas biggest flaw improve it?

Remember this was a mechanical device. Holding the signal in the reflector, rotating the device, and then releasing the signal, that would have been very difficult. But also remember that what made ...
gnasher729's user avatar
  • 1,218
1 vote

Why the permutation of the right hand rotor given in Rejewski's paper is $PNP^{-1}$?

When ring setting is 01 (A) and indicator shown through the corresponding window is A (01) as well, the wiring core is at its home position. Suppose ring setting is $r$ (variable $r$ not letter $\tt R$...
Chan Tai Man's user avatar
1 vote
Accepted

Enigma Questions: Eliminating the can't encode to itself flaw? Maybe not a flaw

The issue here is that you have a cryptographic scheme that is easy to implement in software, but not in the electro-mechanical technology of the Enigma machine. Mathematically, the Umkehrwalze pairs ...
Daniel S's user avatar
  • 23.6k
1 vote

Problem with implementation of Enigma Machine

Not sure if you figured this out. The process flow without the plugboard is more like; Press key on keyboard. Right rotor moves one step. 2a) If right rotor notch at prowl, rotate middle rotor 2b) If ...
DJ in Colorado's user avatar
1 vote

Problem with implementation of Enigma Machine

There are many accessible resources. As @kodlu has suggested, page 25 of the operation manual for the Enigma Cipher Machine Simulator by Dirk Rijmenants has all the necessary information. Dirk ...
Chan Tai Man's user avatar
1 vote

Enigma machine rotor internal wiring question

One other point, rotor wiring was not fixed. I'm not sure when they change the rotor, but they had ring settings. This changed the offset of the output side of the rotor. For a rotor where A translate ...
DJ in Colorado's user avatar
1 vote

Enigma machine rotor internal wiring question

I had this same question and reached out to Dan Perera the Director of the Enigma Museum and EnigmaMuseum.com We had some back and forth and his last letter sent was this: Yes. Enigma rotors can be ...
fnielson1's user avatar
1 vote

Enigma Machine rotors math

There are three small mistakes. The first two are related. Along the outward signal path, you are absolutely right to change the value by +r1 before entering the wire core of rotor α1. It translates ...
Chan Tai Man's user avatar
1 vote

Enigma - How many possibilities does the plugboard have?

The above answer is correct, but I know from teaching this problem to others some still have trouble grasping why it is right. If that is you, think of it this way: You have ten wires. Consider them ...
Tom Wilcox's user avatar

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