Uebung 03

.idea/misc.xml

@@ -1,4 +1,4 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <project version="4">
-  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.9 (python)" project-jdk-type="Python SDK" />
+  <component name="ProjectRootManager" version="2" project-jdk-name="Python 3.9 (UNI_Python)" project-jdk-type="Python SDK" />
 </project>

.idea/python.iml

@@ -2,9 +2,10 @@
 <module type="PYTHON_MODULE" version="4">
   <component name="NewModuleRootManager">
     <content url="file://$MODULE_DIR$">
+      <excludeFolder url="file://$MODULE_DIR$/Virtualenv" />
       <excludeFolder url="file://$MODULE_DIR$/venv" />
     </content>
-    <orderEntry type="inheritedJdk" />
+    <orderEntry type="jdk" jdkName="Python 3.9 (UNI_Python)" jdkType="Python SDK" />
     <orderEntry type="sourceFolder" forTests="false" />
   </component>
 </module>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="" vcs="Git" />
+  </component>
+</project>

ha_02/loosen_janniclas_1540907_03.py

@@ -0,0 +1,114 @@
+# APPROACH: All keyboard keys can be interpreted as an ASCII-Code.
+# => Shift them on the ascii table, with the factor of shift
+# COMMENT: Admittedly, this cipher everything else then secure, but it serves its purpose.
+# => This implementation can create 256 different encryption mappings
+import time
+
+
+def shift_cipher(shift):
+    codes = {}
+    for char_code in range(0, 255):  # all ASCII-letters
+        char = chr((char_code + shift) % 255)
+        codes[chr(char_code)] = char
+    return codes
+
+
+# OBSERVATION: If the encryption map is known, anyone can decode the text.
+# => Security of this procedure depends on how many combinations the cipher algorithm creates.
+# COMMENT: Thanks to the weak cipher, a brute force attack cracks the encryption after a maximum of 256 attempts.
+def caesar(text, cipher, mode):
+    mode = mode.upper()
+    if mode not in ["ENCODE", "DECODE"]:  # Use 'in' to check for multiple conditions
+        return text
+
+    tokens = list(text)
+    if mode == "DECODE":
+        cipher = {value: key for key, value in cipher.items()}
+
+    for i in range(len(tokens)):
+        if tokens[i] in cipher:  # Check if the character exists in the cipher before replacing
+            tokens[i] = cipher[tokens[i]]
+    return "".join(tokens)
+
+
+# COMMENT: Ciphers are binary bijective mappings over an alphabet A, of which |A|! exist (for ours 256!).
+# In practice, security should be strengthened through better cipher algorithms.
+# Because our cipher works so poorly, here is an optimized variant of the caesar process.
+# APPROACH: Set a starting position for the encryption and then encrypt recursively to the right and left.
+# => An Encryption can only be successful, if the starting point is known.
+# => An brute force attack cracks the encryption after a maximum of 256*len(text) attempts.
+def caesar_amplified(text, pos, cipher, mode):
+    mode = mode.upper()
+    if mode not in ["ENCODE", "DECODE"]:  # Use 'in' to check for multiple conditions
+        return text
+
+    tokens = list(text)
+    if mode == "DECODE":
+        cipher = {value: key for key, value in cipher.items()}
+
+    tokens[pos] = cipher[tokens[pos]]
+    tokens = caesar_recursive(tokens, pos - 1, cipher, "l")  # start left recursion
+    tokens = caesar_recursive(tokens, pos + 1, cipher, "r")  # start right recursion
+    return "".join(tokens)
+
+
+def caesar_recursive(tokens, pos, cipher, mode):
+    if pos == -1 or pos == len(tokens):
+        return tokens
+    cipher = update_cipher(cipher)
+    tokens[pos] = cipher[tokens[pos]]
+    if mode == "l":
+        return caesar_recursive(tokens, pos - 1, cipher, "l")
+    else:
+        return caesar_recursive(tokens, pos + 1, cipher, "r")
+
+
+def update_cipher(codes_old):
+    codes_new = {}
+    for key, value in codes_old.items():
+        codes_new[key] = codes_old[codes_old[key]]
+    return codes_new
+
+
+# Write message into these lines:
+string = ''' 
+Liebe/r Empfänger,
+
+Herzliche Grüße aus dem hohen Norden! Ich hoffe, diese Nachricht erreicht dich in guter Verfassung und fügt einen Hauch 
+von festlicher Stimmung zu deinem Tag hinzu.
+
+Santa und seine Wichtel arbeiten fleißig daran, diese Jahreszeit für alle magisch zu gestalten. Die Werkstatt ist voller 
+Aktivität, während Spielzeuge mit Sorgfalt hergestellt werden.
+
+Ich wünsche dir Freude, Gelächter und einen festlichen Geist, der dein Herz erwärmt. Genieße die Magie der Feiertage!
+
+Herzliche Grüße,
+Rudolph
+'''
+enc_time = time.time()
+encoded = caesar(string, shift_cipher(2), "ENCODE")
+enc_time = (time.time() - enc_time) * 1000  # Convert to milliseconds
+
+dec_time = time.time()
+decoded = caesar(encoded, shift_cipher(2), "DECODE")
+dec_time = (time.time() - dec_time) * 1000  # Convert to milliseconds
+
+print("Encoded Caesar-Encryption: (calculated in " + str(enc_time) + "ms)")
+print(encoded + "\n")
+print("Decoded Caesar-Encryption:  (calculated in " + str(dec_time) + "ms)")
+print(decoded)
+
+print("\n")
+
+enc_rec_time = time.time()
+encoded_rec = caesar_amplified(string, 5, shift_cipher(2), "ENCODE")
+enc_rec_time = (time.time() - enc_rec_time) * 1000  # Convert to milliseconds
+
+dec_rec_time = time.time()
+decoded_rec = caesar_amplified(encoded_rec, 5, shift_cipher(2), "DECODE")
+dec_rec_time = (time.time() - dec_rec_time) * 1000  # Convert to milliseconds
+
+print("Encoded Caesar-Encryption amplified: (calculated in " + str(enc_rec_time) + "ms)")
+print(encoded_rec + "\n")
+print("Decoded Caesar-Encryption amplified: (calculated in " + str(dec_rec_time) + "ms)")
+print(decoded_rec)