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)