Python-сообщество

 abc = list("abcdefghijklmnopqrstuvwxyz")
ABC = list("ABCDEFGHIJKLMNOPQRSTUVWXYZ")
word = input()
key = input()
global wordcount
global count
global abcup
abcup = list()
global keycount
def code(word, key):
    word = list(word)
    key = list(key)
    a = len(word)
    acopy = a
    while(a):
        if(word[count].isupper()):
            wordcount = abc.index(word[count])
            abcup[word[count]] = 0
        else:
            wordcount = ABC.index(word[count])
            abcup[word[count]] = 1
        if(key[count].isupper()):
            keycount = abc.index(key[count])
        else:
            keycount = ABC.index(key[count])
        coded = list()
        coded[count] = wordcount + keycount
        count = count + 1
        a = a - 1
    count = 0
    while(acopy):
        if(abcup[count] == 1):
            keycount = ABC.index(coded[count])
            coded[count] = keycount
        else:
            keycount = abc.index(coded[count])
        count = count + 1
        acopy = acopy - 1
    return(coded)
'''def decode(word, key):
    word = list(word)
    key = list(key)
    '''
code(word, key)

 tabula_recta = ["".join([ chr(x) for x in xrange(97+y, 123+y) if x < 123 ] + [ chr(x-123+97) for x in xrange(97+y, 123+y) if x >= 123 ]) for y in xrange(26) ]
 
def norm_key(key, word):
	return key * (len(word)//len(key)) + key[:len(word)%len(key)]
 
def coder(word, key):
	return "".join([ tabula_recta[ord(x)-97][ord(y)-97] for (i,x) in enumerate(word) for (n,y) in enumerate(norm_key(key, word)) if n == i ])
 
def decoder(word, key):
	return "".join([ chr(tabula_recta[ord(x)-97].index(y)+97) for (i,x) in enumerate(norm_key(key, word)) for (n,y) in enumerate(word) if n == i ])
  
>>> coder("rodegast", "lord")
'ccuhrojw'
>>> decoder("ccuhrojw", "lord")
'rodegast'

 def vegenere(text: str, key: str, encrypt: bool):
	return "".join([chr((ord(text[a]) + (-ord(key[a % len(key)]) if not encrypt else ord(key[a % len(key)])) ) % 0x110000) for a in range(text.__len__())])

 list.index; list[index]