def decode(self, ctext: T) -> Optional[U]:
"""
Takes an encoded string and attempts to decode it according to the Atbash cipher.
The Atbash cipher is a very simple substitution cipher without a key.
It operates by replacing every letter in the input by its 'counterpoint'
in the alphabet. Example: A -> Z, B -> Y, ... , M -> N and vice versa.
"""
result = ""
letters = list("abcdefghijklmnopqrstuvwxyz")
atbash_dict = {letters[i]: letters[::-1][i] for i in range(26)}
# Ensure that ciphertext is a string
if type(ctext) == str:
# Normalize the string to all-lowercase letters
ctext = ctext.lower()
else:
return None
for letter in ctext:
if letter in atbash_dict.keys():
# Match every letter of the input to its atbash counterpoint
result += atbash_dict[letter]
else:
# If the current character is not in the defined alphabet,
# just accept it as-is (useful for numbers, punctuation,...)
result += letter
return result
def decode(self, ctext: T) -> Optional[U]:
"""
Takes an encoded string and attempts to decode it according to the Atbash cipher.
The Atbash cipher is a very simple substitution cipher without a key.
It operates by replacing every letter in the input by its 'counterpoint'
in the alphabet. Example: A -> Z, B -> Y, ... , M -> N and vice versa.
"""
result = ""
atbash_dict = {self.ALPHABET[i]: self.ALPHABET[::-1][i] for i in range(26)}
for letter in ctext.lower():
if letter in atbash_dict.keys():
# Match every letter of the input to its atbash counterpoint
result += atbash_dict[letter]
else:
# If the current character is not in the defined alphabet,
# just accept it as-is (useful for numbers, punctuation,...)
result += letter
return fix_case(result, ctext)