Virtual Talk | LACIDA - A Polish Cryptomachine

Jerry McCarthy is a Volunteer Docent at The National Museum of Computing (TNMOC), Bletchley and an occasional speaker at the Piłsudski Institute, Hammersmith, London.
The talk starts with a brief description of the German 3-rotor Enigma and a summary of the various methods which Polish mathematicians and engineers created to decode messages sent by Enigma.
The talk the moves on to a Polish designed machine, the LACIDA, which has some similarities to Enigma but also some major differences. The two machines are compared and contrasted and their relative advantages and disadvantages discussed.
The speaker then demonstrates his software simulation; this is followed by a Q&A session.

[@embeDes]

Thank you very much! Greetings from Poland!

[@CamTarn]

Fascinating talk, thank you!

[@andrzejsmuga7293]

Great work!

[@GreatPolishWingedHussars]

It is important to remember these great Poles who did great things in such difficult times. Their hard work saved many of the Allies' lives in the fight against Germany.

[@Conenion]

Excellent talk! Thank you.

[@matambale]

Very much appreciated sir, thank you.

[@trix3121]

I did meet the late wife of Ludomir Danilewicz in the 90s (Maria Danilewicz Zielińska). She resided outside Lisbon and was a well known figure in the Polish expatriate community. I wish I would've asked her about what she knew about the whereabouts of LACIDA. She would have been on the same evacuation route via Ukraine.

[@alastairdickins]

Thank you, most interesting. Can you say how the rotors implemented having af different number of inputs from outputs?

[@migalito1955]

I have this presentation playing in the background as I work in my shop towards the aim of building a Tim Hunkin style mechanical clock. I chose this video because having two graduate degrees in mathematics and having spent some time years ago towards understanding one way functions or the basis of math based cryptography I find its interesting. On the other hand at the risk of being pedantic I believe the math algorithim the gentleman refers to that tests a cipher for coinciding with a human language is a bit overstated. By this I mean I am almost surely certain that it behaves like a similar test to check whether a number is prime or not where the outcome is not guaranteed, rather the test indicates a high probability of the number being prime or in the case of the cipher a high probability of the cipher being human based. Without going into details I would not bet my life on either one being spot on for various reasons, but they are seemingly better than nothing.

[@fabriziodutto7508]

Interesting, but it is not very clear at some point, in example, @12:44, you said "So, for the 29th of November, which is today... " and then all you said after the "reflector wheel" is not supported by the data shown for the 29th of November. So all the explanation went suddenly weird. Not only that, but @13:50, when you explain where the cables are connected, it is not clear where the "A" plug should be placed, and even in the case I guess it is "under" the "A" letter, it seems to me connected to a "J" not to an "M"... Well, after that I decided I'm too dumb because it is too hard to me to understand the explanation, so I gave up... Merry Christmas.

[@jerrymccarthy5954]

Please don't give up yet; I'll check what I said and put up another comment shortly. Thanks for the Christmas Greetings and, belatedly, the same to you.

[@jerrymccarthy5954]

Your first point: you are quite right. Having read out the correct UKW/reflector value, my eye then went up one line and the rest of the data came from the 30th November line. I was giving this talk on two consecutive days, and must have forgotten what day of the month it was :-) . Your second point; quite right again; "A" is indeed connected to "J". I have no explanation for that one :-( !

[@fabriziodutto7508]

@@jerrymccarthy5954 It's a very interesting argument for me, I was unhappy because I didn't understand. Also my poor English knowledge, unfortunately, didn't came to my help. So maybe my brain is still alive! I'm happy to know it. I will see the video again taking the 30th November data instead of the 29th And also the ("A" to the "J") thing. Happy holidays! Stay safe.