Renamed trafid_cipher.py to trifid_cipher.py and added doctests

DIRECTORY.md

@@ -119,7 +119,7 @@
   * [Shuffled Shift Cipher](ciphers/shuffled_shift_cipher.py)
   * [Simple Keyword Cypher](ciphers/simple_keyword_cypher.py)
   * [Simple Substitution Cipher](ciphers/simple_substitution_cipher.py)
-  * [Trafid Cipher](ciphers/trafid_cipher.py)
+  * [Trifid Cipher](ciphers/trifid_cipher.py)
   * [Transposition Cipher](ciphers/transposition_cipher.py)
   * [Transposition Cipher Encrypt Decrypt File](ciphers/transposition_cipher_encrypt_decrypt_file.py)
   * [Vigenere Cipher](ciphers/vigenere_cipher.py)

ciphers/trafid_cipher.py → ciphers/trifid_cipher.py

@@ -1,135 +1,197 @@
-# https://en.wikipedia.org/wiki/Trifid_cipher
-from __future__ import annotations
-
-
-def __encrypt_part(message_part: str, character_to_number: dict[str, str]) -> str:
-    one, two, three = "", "", ""
-    tmp = []
-
-    for character in message_part:
-        tmp.append(character_to_number[character])
-
-    for each in tmp:
-        one += each[0]
-        two += each[1]
-        three += each[2]
-
-    return one + two + three
-
-
-def __decrypt_part(
-    message_part: str, character_to_number: dict[str, str]
-) -> tuple[str, str, str]:
-    tmp, this_part = "", ""
-    result = []
-
-    for character in message_part:
-        this_part += character_to_number[character]
-
-    for digit in this_part:
-        tmp += digit
-        if len(tmp) == len(message_part):
-            result.append(tmp)
-            tmp = ""
-
-    return result[0], result[1], result[2]
-
-
-def __prepare(
-    message: str, alphabet: str
-) -> tuple[str, str, dict[str, str], dict[str, str]]:
-    # Validate message and alphabet, set to upper and remove spaces
-    alphabet = alphabet.replace(" ", "").upper()
-    message = message.replace(" ", "").upper()
-
-    # Check length and characters
-    if len(alphabet) != 27:
-        raise KeyError("Length of alphabet has to be 27.")
-    for each in message:
-        if each not in alphabet:
-            raise ValueError("Each message character has to be included in alphabet!")
-
-    # Generate dictionares
-    numbers = (
-        "111",
-        "112",
-        "113",
-        "121",
-        "122",
-        "123",
-        "131",
-        "132",
-        "133",
-        "211",
-        "212",
-        "213",
-        "221",
-        "222",
-        "223",
-        "231",
-        "232",
-        "233",
-        "311",
-        "312",
-        "313",
-        "321",
-        "322",
-        "323",
-        "331",
-        "332",
-        "333",
-    )
-    character_to_number = {}
-    number_to_character = {}
-    for letter, number in zip(alphabet, numbers):
-        character_to_number[letter] = number
-        number_to_character[number] = letter
-
-    return message, alphabet, character_to_number, number_to_character
-
-
-def encrypt_message(
-    message: str, alphabet: str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ.", period: int = 5
-) -> str:
-    message, alphabet, character_to_number, number_to_character = __prepare(
-        message, alphabet
-    )
-    encrypted, encrypted_numeric = "", ""
-
-    for i in range(0, len(message) + 1, period):
-        encrypted_numeric += __encrypt_part(
-            message[i : i + period], character_to_number
-        )
-
-    for i in range(0, len(encrypted_numeric), 3):
-        encrypted += number_to_character[encrypted_numeric[i : i + 3]]
-
-    return encrypted
-
-
-def decrypt_message(
-    message: str, alphabet: str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ.", period: int = 5
-) -> str:
-    message, alphabet, character_to_number, number_to_character = __prepare(
-        message, alphabet
-    )
-    decrypted_numeric = []
-    decrypted = ""
-
-    for i in range(0, len(message) + 1, period):
-        a, b, c = __decrypt_part(message[i : i + period], character_to_number)
-
-        for j in range(len(a)):
-            decrypted_numeric.append(a[j] + b[j] + c[j])
-
-    for each in decrypted_numeric:
-        decrypted += number_to_character[each]
-
-    return decrypted
-
-
-if __name__ == "__main__":
-    msg = "DEFEND THE EAST WALL OF THE CASTLE."
-    encrypted = encrypt_message(msg, "EPSDUCVWYM.ZLKXNBTFGORIJHAQ")
-    decrypted = decrypt_message(encrypted, "EPSDUCVWYM.ZLKXNBTFGORIJHAQ")
-    print(f"Encrypted: {encrypted}\nDecrypted: {decrypted}")
+from __future__ import annotations
+
+"""
+The trifid cipher is a classical cipher invented by Félix Delastelle in 1902
+
+Wikipedia : https://en.wikipedia.org/wiki/Trifid_cipher
+
+It takes in input the plaintext and the key and encrypts it
+For decryption, the same key used in the encryption is required
+
+Syntax : encrypt_message(plaintext, key)
+         decrypt_message(encrypted, key)
+"""
+
+
+def __encrypt_part(message_part: str, character_to_number: dict[str, str]) -> str:
+    one, two, three = "", "", ""
+    tmp = []
+
+    for character in message_part:
+        tmp.append(character_to_number[character])
+
+    for each in tmp:
+        one += each[0]
+        two += each[1]
+        three += each[2]
+
+    return one + two + three
+
+
+def __decrypt_part(
+    message_part: str, character_to_number: dict[str, str]
+) -> tuple[str, str, str]:
+    tmp, this_part = "", ""
+    result = []
+
+    for character in message_part:
+        this_part += character_to_number[character]
+
+    for digit in this_part:
+        tmp += digit
+        if len(tmp) == len(message_part):
+            result.append(tmp)
+            tmp = ""
+
+    return result[0], result[1], result[2]
+
+
+def __prepare(
+    message: str, alphabet: str
+) -> tuple[str, str, dict[str, str], dict[str, str]]:
+    """__prepare validates the entered message and alphabet to check if
+    it satisfies all the given requirements:
+
+       1) message must not contain numbers like 1,2,3 etc
+       2) Key must have all the alphabets the message has
+       3) Length of the key has to be 27
+
+       >>> __prepare("hello", "ABCDEHG")
+       Traceback (most recent call last):
+       ...
+       KeyError: 'Length of alphabet has to be 27.'
+
+    >>> __prepare("hello", "AABCDEFGGIJKLMNOPQRSTUVWXYZ")
+    Traceback (most recent call last):
+    ...
+     raise ValueError("Each message character has to be included in alphabet!")
+    ValueError: Each message character has to be included in alphabet!
+    """
+    # Validate message and alphabet, set to upper and remove spaces
+    alphabet = alphabet.replace(" ", "").upper()
+    message = message.replace(" ", "").upper()
+
+    # Check length and characters
+    if len(alphabet) != 27:
+        raise KeyError("Length of alphabet has to be 27.")
+    for each in message:
+        if each not in alphabet:
+            raise ValueError("Each message character has to be included in alphabet!")
+
+    # Generate dictionares
+    numbers = (
+        "111",
+        "112",
+        "113",
+        "121",
+        "122",
+        "123",
+        "131",
+        "132",
+        "133",
+        "211",
+        "212",
+        "213",
+        "221",
+        "222",
+        "223",
+        "231",
+        "232",
+        "233",
+        "311",
+        "312",
+        "313",
+        "321",
+        "322",
+        "323",
+        "331",
+        "332",
+        "333",
+    )
+    character_to_number = {}
+    number_to_character = {}
+    for letter, number in zip(alphabet, numbers):
+        character_to_number[letter] = number
+        number_to_character[number] = letter
+
+    return message, alphabet, character_to_number, number_to_character
+
+
+def encrypt_message(
+    message: str, alphabet: str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ.", period: int = 5
+) -> str:
+    """
+    encrypt_message(message, alphabet, period) encrypts the message using the alphabet
+    and period
+
+    1) If not provided, default alphabet is taken as "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    2) If not provided, default period is taken as 5
+    3) message is a compulsory argument
+
+    >>> print(encrypt_message("hello world"))
+    BOJN.WKPOY
+
+    >>> print(encrypt_message("how are you", "BAECDHFGIJKLMNOPRQTSUVXWZY."))
+    HDM.XGULQ
+
+    >>> print(encrypt_message("all aboard the train", "BAECDHFGIJKLMNOPRQTSUVXWZY.", 4))
+    DBAYCKFXFCKIVEFON
+    """
+    message, alphabet, character_to_number, number_to_character = __prepare(
+        message, alphabet
+    )
+    encrypted, encrypted_numeric = "", ""
+
+    for i in range(0, len(message) + 1, period):
+        encrypted_numeric += __encrypt_part(
+            message[i : i + period], character_to_number
+        )
+
+    for i in range(0, len(encrypted_numeric), 3):
+        encrypted += number_to_character[encrypted_numeric[i : i + 3]]
+
+    return encrypted
+
+
+def decrypt_message(
+    message: str, alphabet: str = "ABCDEFGHIJKLMNOPQRSTUVWXYZ.", period: int = 5
+) -> str:
+    """
+    decrypt_message(message, alphabet, period) decrypts the message using the alphabet
+    and period
+
+    1) If not provided, default alphabet is taken as "ABCDEFGHIJKLMNOPQRSTUVWXYZ"
+    2) If not provided, default period is taken as 5
+    3) message is a compulsory argument
+
+    >>> print(decrypt_message("BOJN.IYSS"))
+    HELLOGUYS
+
+    >>> print(decrypt_message("KHQDYRSTJWPYTEAOC", "QWERTYUIOPASDFGHJKLZXCVBNM."))
+    ALLABOARDTHETRAIN
+
+    >>> print(decrypt_message("DBAYCKFXFCKIVEFON", "BAECDHFGIJKLMNOPRQTSUVXWZY.", 4))
+    ALLABOARDTHETRAIN
+    """
+    message, alphabet, character_to_number, number_to_character = __prepare(
+        message, alphabet
+    )
+    decrypted_numeric = []
+    decrypted = ""
+
+    for i in range(0, len(message) + 1, period):
+        a, b, c = __decrypt_part(message[i : i + period], character_to_number)
+
+        for j in range(len(a)):
+            decrypted_numeric.append(a[j] + b[j] + c[j])
+
+    for each in decrypted_numeric:
+        decrypted += number_to_character[each]
+
+    return decrypted
+
+
+if __name__ == "__main__":
+    import doctest
+
+    doctest.testmod()