I think the author is too quick to dismiss the impact of the plugboard.
IC attacks only the rotor settings [...] Once you’ve found the right rotors and positions, you can solve the plugboard separately using frequency analysis.
So two steps: first solve for rotor settings with IC analysis, then solve the plugboard.
But IC analysis can't find the solution, just propose a lot of candidates among which a human can spot the correct one by looking for intelligible German text. And how can you spot intelligible German text if some letters are swapped by the plugboard?
Yeah something is wrong there, and I don't see actual breaks in the post, though maybe I missed something. Solving the rotors to get to the plugboard isn't so easy! The permutation changes every character, as the rotors advance.
Comments
I think the author is too quick to dismiss the impact of the plugboard.
So two steps: first solve for rotor settings with IC analysis, then solve the plugboard.
But IC analysis can't find the solution, just propose a lot of candidates among which a human can spot the correct one by looking for intelligible German text. And how can you spot intelligible German text if some letters are swapped by the plugboard?
Yeah something is wrong there, and I don't see actual breaks in the post, though maybe I missed something. Solving the rotors to get to the plugboard isn't so easy! The permutation changes every character, as the rotors advance.