Взлом Vigenere cipher

Скрипты

python

def encryption(plaintext, keyword):

   txt_len = len(plaintext)
   keyword *= txt_len // len(keyword) + 1
   keyword = keyword[:txt_len]
   encoded = ""
   for c in range(txt_len):
       newchar = ord(plaintext[c]) + ord(keyword[c]) - 194
       newchar %= 25
       encoded += chr(newchar + 97)  # 97 = ord('a')
   return encoded