python caesar cipher
plaintext = input("Please enter your plaintext: ") shift = input("Please enter your key: ") alphabet = "abcdefghijklmnopqrstuvwxyz" ciphertext = "" # shift value can only be an integer while isinstance(int(shift), int) == False: # asking the user to reenter the shift value shift = input("Please enter your key (integers only!): ") shift = int(shift) new_ind = 0 # this value will be changed later for i in plaintext: if i.lower() in alphabet: new_ind = alphabet.index(i) + shift ciphertext += alphabet[new_ind % 26] else: ciphertext += i print("The ciphertext is: " + ciphertext)