Cryptography: Caesar Cipher Python

hello and welcome back to a little project of making the best cipher in the world just kidding but in this video we try to code the Caesar cipher in Python so let's get started and I've actually already started writing the alphabet I didn't want to mess that part up not on camera but so what we want to do after having our alphabet I included a space because it makes that messages more readable so what we want to do after every one we want to have a dictionary that map's each letter to a number and then we also want to have a mapping back so we can have a dictionary that map's a number to a letter one way we can do this is we create a letter to index want to make a dictionary and so this is one way of doing that we use for each in the alphabet we have a letter which is the range of the Len length of the alphabet so this will be 0 1 2 etc and so a for example would be mapped to 0 B would be mapped to 1 and that this is what the zip function does is that it maps a 2-0 etc and then we make a dictionary out of that now we need to have one more dictionary that map's the letter the index to a letter right this maps a letter to a index and essentially the same thing except ever now we want to do the reverse so it should be something like this and then what is it that we want to do well we want to have a function that encrypts and it should encrypt a message and it should do it with a shift that we could set a standard to make perhaps as we did in the last video that the shift should be 3 and then we want to also have a function of decrypt and it should decrypt a cipher ciphered text and also with a shift and they want to have a main function that perhaps runs runs these function so just a little skeleton of the code we want to write so in if we start with the encrypt function then we want to first have a so the cipher text is empty from the beginning or if you're just writing cipher then we want to for we want to go to each letter in our message so for letter in message then we want to first map that specific letter to a number then we use letter to index of that specific letter then we add a shift the shift that's specified in the input and then we take that modulus the length of our alphabet and we can call this the number or perhaps index we call this index and then what we want to do is that we want to call our index to letter of that specific index and then we wanted what we can do is that we can call this the shifted letter and then the cipher will be added that that shifted letter will be added to our cipher so shifted letter and then at the end we just want to return the cipher so for example if we have a message that is attack at noon and notice that we can write this because we included spaces in our alphabet then we can say that our encrypted message will be encrypt of the message and we don't have to write the shift since we use a shift of 3 but we can write it just to be clear and then we can say that we can just print the encrypted message and the code seems to be working and this so we can see at least at a becomes D makes sense and let's just make sense T becomes X yeah no way it should be at W all right I said I didn't want to mess this up on camera and I still messed it up i SUV W yeah this this should make sense yeah all right so we want to now after we've done that is that we want to run the decryption so decrypted start with a empty message empty string so for letter in our cipher text we now want to do essentially the exact same thing as we did previously right so we can just probably copy this know what we want to do is that we want to subtract this and that's that should be it so then we have a decrypted now we really turn a decrypted and some of the ultimate test let's see if we when we run the decrypt of our encrypted message we should get back the original message so a decrypted message and then let's just say print original message or string or mess it will actually it's just already a string so just plus message copies encrypted message and decrypted message all right let's hope that it works all right so it seems to be working original message attack at noon and then we get this and then the decrypted becomes again attack at noon so hopefully you were able to follow of that if you have any questions about the code or anything then please leave them below thank you so much for watching and I hope you have a great day