Re: M4 project

steve-ZMQM5VTtYHJ+cjeuK/[email protected] wrote:
> 
> I'm contributing to the M4 project, but am a bit surprised at the
> tactics. I don't have a problem with the *concept* as such, but with the
> bit that says "lock the middle wheel ring at 'A'".

If M4, 40% chance there is no double notch wheel. 60% chance with Service wheels that there is no slow turn-over. Therefore the tactic is to try the easier options first.  If that fails then try different rings. 


> no slower wheel to use its notch. The fast wheel ring is dealt-with as
> it must be - wrong ring there is fatal.

Wrong fast ring is not always fatal. See todays break. Many were at incorrect fast rings. If it is out it only damages some letters. You get short stretches of garble every 26 letters. Usually there is enough left to hill climb, depending on the plain text content.


> And why do M3 at all? With the M4 fourth wheel at 'A' it emulates an M3
> anyway! That was the secret of the short weather cipher crib after all.

I thought M3 (equivalent to Greek at A) was done first, This setting would not be included in a subsequent M4 run. Although I'm not involved in the project so don't know all the details.

Regards,

Geoff