helpers.py 文件源码

def do_simple_substitution(ciphertext, pt_charset, ct_charset):
   '''
   Perform simple substitution based on character sets

   Simplifies the use of string.translate(). If, for instance, you wish to
   transform a ciphertext where 'e' is swapped with 't', you would call this
   function like so:

   do_simple_substitution('Simplt subeieueion ciphtrs art silly','et','te')

   ciphertext - A string to translate
   pt_charset - The character set of the plaintext, usually 'abcdefghijk...xyz'
   ct_charset - The character set of the ciphertext
   '''
   #translate ciphertext to plaintext using mapping
   return string.translate(ciphertext, string.maketrans(ct_charset, pt_charset))


# TODO: Implement chi square