I want to get specific values from a for loop to add to another string to create a vigenere cipher.
here's the code.
userinput = input('enter message')
keyword = input('enter keyword')
new = ''
for a in keyword:
pass
for i in (ord(x) for x in userinput):
if 96 < i < 123: #lowercase
new += chr(97 + (i+ord(a)-97)#keeps all values in alphabet
print(new)
so the answer i want if i do 'abcd' as my message and 'ab' as my keyword the desired outcome is 'bddf' as 'a' + 'a' is 'b' and 'b' + 'b' = 'd' and etc. how would i change the code to match my desired outcome or will i have to change it completely and how would i go about doing so.
try this (you are missing the mod 26-part):
from itertools import cycle
plaintext = input('enter message: ')
keyword = input('enter keyword: ')
def chr_to_int(char):
return 0 if char == 'z' else ord(char)-96
def int_to_chr(integer):
return 'z' if integer == 0 else chr(integer+96)
def add_chars(a, b):
return int_to_chr(( chr_to_int(a) + chr_to_int(b) ) % 26 )
def vigenere(plaintext, keyword):
keystream = cycle(keyword)
ciphertext = ''
for pln, key in zip(plaintext, keystream):
ciphertext += add_chars(pln, key)
return ciphertext
ciphertext = vigenere(plaintext, keyword)
print(ciphertext)
if you like list comprehensions, you can also write
def vigenere(plaintext, keyword):
keystream = cycle(keyword)
return ''.join(add_chars(pln, key)
for pln, key in zip(plaintext, keystream))
UPDATE
updated according to the wish that a+a=b. note that z is in that case the neutral element for the addition (z+char=z).
