From 1ea46419ca7e2ce58fff1bbd5b0761a2020dac2f Mon Sep 17 00:00:00 2001
From: David Huh <38101884+qt1337@users.noreply.github.com>
Date: Mon, 18 Oct 2021 11:42:09 +0200
Subject: [PATCH] :sparkles: Added comments and bruteforce example

---
 Verschiebe-Chiffre.py | 58 +++++++++++++++++++++++++++++++++++++------
 1 file changed, 50 insertions(+), 8 deletions(-)

diff --git a/Verschiebe-Chiffre.py b/Verschiebe-Chiffre.py
index 1dfbfad..34cb9a8 100644
--- a/Verschiebe-Chiffre.py
+++ b/Verschiebe-Chiffre.py
@@ -1,13 +1,48 @@
 def encrypt_text(cleartext: str = 'Bitcoin', incrementation: int = 13):
-    encrypted_text = ''
+    """
+    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:
-        encrypted_text += increment_char(char, incrementation)
+        shifted_text += increment_char(char, incrementation)
 
-    return encrypted_text
+    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 \
@@ -19,15 +54,22 @@ def increment_char(char, incrementation: int = 1):
     return str(new_char_in_bytes)[2]
 
 
-def decrypt_text(encrypted_text: str = 'Ovgpbva', incrementation: int = 13):
-    cleartext = ''
+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)
 
-    for char in encrypted_text:
-        cleartext += increment_char(char, 26 - incrementation)
+    :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)
 
-    return cleartext
+    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()