diff --git a/ciphers/baconian_cipher.py b/ciphers/baconian_cipher.py new file mode 100644 index 000000000..027fbc50e --- /dev/null +++ b/ciphers/baconian_cipher.py @@ -0,0 +1,89 @@ +""" +Program to encode and decode Baconian or Bacon's Cipher +Wikipedia reference : https://en.wikipedia.org/wiki/Bacon%27s_cipher +""" + +encode_dict = { + "a": "AAAAA", + "b": "AAAAB", + "c": "AAABA", + "d": "AAABB", + "e": "AABAA", + "f": "AABAB", + "g": "AABBA", + "h": "AABBB", + "i": "ABAAA", + "j": "BBBAA", + "k": "ABAAB", + "l": "ABABA", + "m": "ABABB", + "n": "ABBAA", + "o": "ABBAB", + "p": "ABBBA", + "q": "ABBBB", + "r": "BAAAA", + "s": "BAAAB", + "t": "BAABA", + "u": "BAABB", + "v": "BBBAB", + "w": "BABAA", + "x": "BABAB", + "y": "BABBA", + "z": "BABBB", + " ": " ", +} + + +decode_dict = {value: key for key, value in encode_dict.items()} + + +def encode(word: str) -> str: + """ + Encodes to Baconian cipher + + >>> encode("hello") + 'AABBBAABAAABABAABABAABBAB' + >>> encode("hello world") + 'AABBBAABAAABABAABABAABBAB BABAAABBABBAAAAABABAAAABB' + >>> encode("hello world!") + Traceback (most recent call last): + ... + Exception: encode() accepts only letters of the alphabet and spaces + """ + encoded = "" + for letter in word.lower(): + if letter.isalpha() or letter == " ": + encoded += encode_dict[letter] + else: + raise Exception("encode() accepts only letters of the alphabet and spaces") + return encoded + + +def decode(coded: str) -> str: + """ + Decodes from Baconian cipher + + >>> decode("AABBBAABAAABABAABABAABBAB BABAAABBABBAAAAABABAAAABB") + 'hello world' + >>> decode("AABBBAABAAABABAABABAABBAB") + 'hello' + >>> decode("AABBBAABAAABABAABABAABBAB BABAAABBABBAAAAABABAAAABB!") + Traceback (most recent call last): + ... + Exception: decode() accepts only 'A', 'B' and spaces + """ + if set(coded) - {"A", "B", " "} != set(): + raise Exception("decode() accepts only 'A', 'B' and spaces") + decoded = "" + for word in coded.split(): + while len(word) != 0: + decoded += decode_dict[word[:5]] + word = word[5:] + decoded += " " + return decoded.strip() + + +if "__name__" == "__main__": + from doctest import testmod + + testmod()