Hi Michael Doornbos, Thank you :-) If you need furhter details for implementing the SIGABA, you may have a look at (1) the MysterytwisterC3 challenges zip; here, you find a paper about the SIGABA's inner workings (www.mysterytwisterc3.org/en/challenges/level-2/sigaba-csp-889-part-1) (2) the source code written in C# (svn.cryptool.org/CrypTool2/trunk/CrypPlugins/SIGABA/SIGABAImplementation.cs). Username "anonymous", passwort blank. Greetings, Nils
hi i'm a french person preparing an oral about different cipher machines used during wwII so thanks for your very useful video ! i have one thing i don't understand : why are the index rotors for ?
Hi thank you, the index rotors are fed with current by the control rotors and output the current to the stepping control. basically they are just changing the input based on their positions and rotations. They never move but since they can be put in any configuration into the machine they are also part of the key. I hope this answers the question 🙂 Greetings, Nils
@@CryptographyForEverybody thank you I think I understood ! i just have two more questions : for the maths of the key space size, why don't you take into account the 2^35.5 for the positions of the rotors ? also, is there any chance you have worked on the purple cipher machine by the japanese side during WWII ? it's also called the type b cipher machine or the code 97 I think thank you for all your work it's really helping 🙏🫶
Nice and well-structured video. Thx Could u pls answer some more questions? - So now we can encrypt and decrypt messages in ct2 with the sigaba emulator by our own. This is done instantly. Do you know how quick this was done by the operators then in history? - What is the weight of such a device? - Will the cryptanalysis algorithms mentioned be implemented someday too? Will they also be open-source?
Hello Ed, Answers to your questions: a) "Do you know how quick this was done by the operators then in history?" --> Not sure how fast they were. I know that Enigma operators often worked in teams of... One operator typed in the plaintext letters and another one read out the ciphertext letters. Often, a third one also morsed the message. Since the U.S. Sigaba was used on battleships and in headquarters and not in the field (in contrast to Enigma), I assume it was operated by only one person. Also, I think, Sigaba could be directly connected to a telewriter... So I think it could be operated fastly (telewriter) or "slowly" (by hand) b) "Will the cryptanalysis algorithms mentioned be implemented someday too? Will they also be open-source?" --> Probably I will implement it. George Lasry told me, that the analysis takes several hours and is rather complex. Therefore, I am not sure which part we will put into CT2. And yes, of course, everything will be open-source :-) Greetings, Nils
Hello Richard Roddenberry, I am by far no expert of the KL-7 :-). But it is a quite interesting machine. I think I will have to look at it in detail to answer that correctly. Maybe, we have to implement it in CT2 and I will also create a video about it. Nevertheless, I think, they always used knowledge gained based on analyses of previous machines for developing the new ones. I think that for example William Friedman was even inspired by Enigma. Knowing Enigma's weaknesses, he designed SIGABA in such a way that it has none of the Enigma weaknesses, e.g. the reflector. Greetings, Nils
