def grille(a, b):
    return chr(65 + (ord(a) + ord(b)) % 26)

def invGrille(a, b):
    return chr(65 + (ord(a) - ord(b)) % 26)

def chiffreAutoclaveV1(phrase:str, cle:str):
    phrase = phrase.upper()
    chiffre = ''
    for c in phrase:
        cle = grille(c, cle)
        chiffre += cle
    return chiffre

def dechiffreAutoclaveV1(chiffre:str, cle:str):
    clair = ''
    for c in chiffre:
        clair += invGrille(c, cle)
        cle = c
    return clair    
  
phrase = 'OPERATIONURGENTE'
cle = 'K'
chiffre = chiffreAutoclaveV1(phrase, cle)
print('Chiffrée :', chiffre)
print('Déchiffrée :', dechiffreAutoclaveV1(chiffre, cle))


def chiffreAutoclaveV2(phrase:str, mot:str):
    phrase = phrase.upper()
    cle = mot.upper() + phrase
    chiffre = ''
    for i, c in enumerate(phrase): chiffre += grille(c, cle[i])
    return chiffre

def dechiffreAutoclaveV2(chiffre:str, mot:str):
    clair = ''
    cle = mot
    for i, c in enumerate(chiffre):
        lettre = invGrille(c, cle[i])
        clair += lettre
        cle += lettre
    return clair

phrase = 'MESSAGEIMPORTANTPOURNESTORLAGIRAFEAUNLONGCOU'
mot = 'POIRIER'
chiffre = chiffreAutoclaveV2(phrase, mot)
print('Chiffrée :', chiffre)
print('Déchiffrée :', dechiffreAutoclaveV2(chiffre, mot))