a key in Vigenere crytosystem is a string of English letter where the case of the letters does not matter.How many different keys for this cryptosystem are there with three four five or six letter?

Question

anonymous · Answer

please help me

freckles · Answer

What can you tell me about Vigenere cryptosystem that could be helpful?

anonymous · Answer

this is exercise. i don t understand it

freckles · Answer

I need to know what you know about the system

anonymous · Answer

this question in Discreet mathematics

freckles · Answer

Like we have 26 letters in the alphabet.
And I assume you can't use the same letter twice.
If the key has length 3, then maybe it is 26*25*24.
But I really don't know anything about the Vigenere cryptosystem so I don't know.

anonymous · Answer

thank you

freckles · Answer

Like does that make sense to you?
We can choose the first letter 26 ways. That means there are 25 ways to choose the 2nd 1 and 24 ways to choose the last one
But like I'm only assuming I know what is happening in the cryptosystem when I actually don't because this is the first time for me seeing the sysem. That is why I was asking for what you have learned about this system.