Merge remote-tracking branch 'origin/master'

Verschiebe-Chiffre.py

@@ -1,33 +0,0 @@
-def encrypt_text(cleartext: str = 'Bitcoin', incrementation: int = 13):
-    encrypted_text = ''
-
-    for char in cleartext:
-        encrypted_text += increment_char(char, incrementation)
-
-    return encrypted_text
-
-
-def increment_char(char, incrementation: int = 1):
-    # converting character to byte
-    char_in_bytes = bytes(char, 'utf-8')[0]
-    if char_in_bytes + incrementation >= 91 and char_in_bytes < 91 \
-            or char_in_bytes + incrementation >= 123:  # z -> 122 | 90 -> Z so go backwards
-        new_char_in_bytes = bytes([char_in_bytes - (26 - incrementation)])
-    else:
-        new_char_in_bytes = bytes([char_in_bytes + incrementation])
-
-    return str(new_char_in_bytes)[2]
-
-
-def decrypt_text(encrypted_text: str = 'Ovgpbva', incrementation: int = 13):
-    cleartext = ''
-
-    for char in encrypted_text:
-        cleartext += increment_char(char, 26 - incrementation)
-
-    return cleartext
-
-
-if __name__ == '__main__':
-    print(encrypt_text())
-    print(decrypt_text())

chapter_one/Verschiebe-Chiffre.py

@@ -0,0 +1,75 @@
+def encrypt_text(cleartext: str = 'Bitcoin', incrementation: int = 13):
+    """
+    This method encrypts a text by shifting each letter by the value of incrementation
+
+    :param cleartext: The secret message to encrypt
+    :param incrementation: How much the letters should be shifted
+    :return: Encrypted text
+    """
+    return shift_text(cleartext, (incrementation % 26))  # '%' to repeat after 26 with 0
+
+
+def decrypt_text(encrypted_text: str = 'Ovgpbva', incrementation: int = 13):
+    """
+    This method decrypts a text by shifting each letter by the value of incrementation
+
+    :param encrypted_text: The encrypted secret message to decrypt
+    :param incrementation: How much the letters should be shifted
+    :return: Decrypted text
+    """
+    return shift_text(encrypted_text, 26 - (incrementation % 26))  # '%' to repeat after 26 with 0
+
+
+def shift_text(cleartext: str, incrementation: int):
+    """
+    This method shifts every letter of a string by the value of incrementation
+    :param cleartext: The string to be shifted
+    :param incrementation: How much the letters should be shifted
+    :return: Shifted text
+    """
+    shifted_text = ''
+
+    for char in cleartext:
+        shifted_text += increment_char(char, incrementation)
+
+    return shifted_text
+
+
+def increment_char(char, incrementation: int = 1):
+    """
+    This method shifts one char by the value of incrementation
+
+    :param char: Char to be shifted
+    :param incrementation: How much the char should be shifted
+    :return: Shifted letter
+    """
+    # converting character to byte
+    char_in_bytes = bytes(char, 'utf-8')[0]
+    if char_in_bytes + incrementation >= 91 and char_in_bytes < 91 \
+            or char_in_bytes + incrementation >= 123:  # z -> 122 | 90 -> Z so go backwards
+        new_char_in_bytes = bytes([char_in_bytes - (26 - incrementation)])
+    else:
+        new_char_in_bytes = bytes([char_in_bytes + incrementation])
+
+    return str(new_char_in_bytes)[2]
+
+
+def brute_force_example(cleartext: str = 'Bitcoin', incrementation: int = 7):
+    """
+    This is an example of how to bruteforce an encrypted text. (Encrypted with Letter-Shifting)
+
+    :param cleartext: The secret message to encrypt and decrypt during bruteforcing
+    :param incrementation: How much the letters should be shifted
+    """
+    encrypted_text = encrypt_text(cleartext, incrementation=incrementation)
+
+    for x in range(26):
+        if cleartext == decrypt_text(encrypted_text, incrementation=x):
+            print(f'Text was shifted by {x} letters.')
+
+
+if __name__ == '__main__':
+    print(encrypt_text())
+    print(decrypt_text())
+
+    brute_force_example()