diff --git a/chapter_one/Multiplikative_Chiffre.py b/chapter_one/Multiplikative_Chiffre.py
index 1dc57b3..b885df6 100644
--- a/chapter_one/Multiplikative_Chiffre.py
+++ b/chapter_one/Multiplikative_Chiffre.py
@@ -18,8 +18,8 @@ def encrypt_text(cleartext: str, key: int):
 
 	for char in cleartext:
 		index = au.get_index_of_letter(char)
-		newIndex = (index * key) % 26
-		resulting += au.get_letter_at_index(newIndex)
+		new_index = (index * key) % 26
+		resulting += au.get_letter_at_index(new_index)
 
 	return resulting
 
@@ -41,8 +41,8 @@ def decrypt_text(ciphertext: str, key: int):
 
 	for char in ciphertext:
 		index = au.get_index_of_letter(char)
-		newIndex = (index * decrypt_key) % 26
-		resulting += au.get_letter_at_index(newIndex)
+		new_index = (index * decrypt_key) % 26
+		resulting += au.get_letter_at_index(new_index)
 
 	return resulting
 
diff --git a/chapter_one/Permutations-Chiffre.py b/chapter_one/Permutations-Chiffre.py
index dbcc97e..849ee4d 100644
--- a/chapter_one/Permutations-Chiffre.py
+++ b/chapter_one/Permutations-Chiffre.py
@@ -13,10 +13,10 @@ def encrypt_text(cleartext: str, key: [int]):
 	resulting = ''
 
 	for char in cleartext:
-		charIndex = au.get_index_of_letter(char)
-		cipherIndex = key.index(charIndex)
-		cipherChar = au.get_letter_at_index(cipherIndex)
-		resulting += cipherChar
+		char_index = au.get_index_of_letter(char)
+		cipher_index = key.index(char_index)
+		cipher_char = au.get_letter_at_index(cipher_index)
+		resulting += cipher_char
 
 	return resulting
 
@@ -31,10 +31,10 @@ def decrypt_text(ciphertext: str, key: [int]):
 	resulting = ''
 
 	for char in ciphertext:
-		charIndex = au.get_index_of_letter(char)
-		clearIndex = key[charIndex]
-		clearChar = au.get_letter_at_index(clearIndex)
-		resulting += clearChar
+		char_index = au.get_index_of_letter(char)
+		clear_index = key[char_index]
+		clear_char = au.get_letter_at_index(clear_index)
+		resulting += clear_char
 
 	return resulting
 
@@ -50,20 +50,22 @@ def generate_key():
 
 	return indices
 
+
 def generate_key_with_keyword(keyword: str):
 	result = []
 
 	for char in keyword:
-		charIndex = au.get_index_of_letter(char)
-		if charIndex not in result:
-			result.append(charIndex)
+		char_index = au.get_index_of_letter(char)
+		if char_index not in result:
+			result.append(char_index)
 
-	remainingIndices = [i for i in range(26-len(result))]
+	remaining_indices = [i for i in range(26 - len(result))]
 
-	result.extend(remainingIndices)
+	result.extend(remaining_indices)
 
 	return result
 
+
 if __name__ == '__main__':
 	key = generate_key_with_keyword('patrick')
 	print(key)
diff --git a/chapter_one/Tausch-Chiffre.py b/chapter_one/Tausch-Chiffre.py
index 03fd32f..44c0131 100644
--- a/chapter_one/Tausch-Chiffre.py
+++ b/chapter_one/Tausch-Chiffre.py
@@ -23,8 +23,8 @@ def encrypt_text(cleartext: str, key1: int, key2: int):
 
 	for char in cleartext:
 		index = au.get_index_of_letter(char)
-		newIndex = (index * key1 + key2) % 26
-		resulting += au.get_letter_at_index(newIndex)
+		new_index = (index * key1 + key2) % 26
+		resulting += au.get_letter_at_index(new_index)
 
 	return resulting
 
@@ -51,8 +51,8 @@ def decrypt_text(ciphertext: str, key1: int, key2: int):
 
 	for char in ciphertext:
 		index = au.get_index_of_letter(char)
-		newIndex = ((index - key2) * decrypt_key1) % 26
-		resulting += au.get_letter_at_index(newIndex)
+		new_index = ((index - key2) * decrypt_key1) % 26
+		resulting += au.get_letter_at_index(new_index)
 
 	return resulting