A historical look at decrypting the Enigma

[Baluncore]

what is repeated substitution?

It depends on context, and what happens between the two substitutions.
Where was the term used?

 

[Swamp Thing]

It depends on context, and what happens between the two substitutions.
Where was the term used?

The last two posts in these results: https://www.physicsforums.com/search/7184615/?q="repeated+substitution"&t=post&c[thread]=1046742&o=date

Edit: I asked because it seemed that Vanadium considered Enigma to be a form of rep. subs. Whereas to me, it seems like a very long one-time pad that you recycle through each time you reach the end?

Edit: Plus, the enemy has copies of all the pads you will ever use (like millions of them) but doesn't know which is the current one.

 

[Baluncore]

Each rotor contained 26 wires that connected the 26 contacts on the left face, to 26 different contacts on the right face. That was in effect a (cyclically changing) letter substitution. With three rotors, and a reflector, there were a total of 7 substitutions. The plugboard was another sparse substitution, since only a few steckers were used to exchange the letters.

I don't think the concept of a long "One Time Pad" is a good model of Enigma. The messages were very much shorter than the rotor sequence length. Enigma was broken by the successive preclusion of possible known rotors, based on each assumed crib. An OTP should be truly random, and so could not possibly be factored into the different rotor combination and order employed that day.