Solve set 1 challenge 4, and add forgotten sample text file

[sandbox] / cryptopals-python / cryptopals.py

diff --git a/cryptopals-python/cryptopals.py b/cryptopals-python/cryptopals.py
index c5d2704..56501a1 100644 (file)
--- a/cryptopals-python/cryptopals.py
+++ b/cryptopals-python/cryptopals.py
@@ -27,6 +27,11 @@ def compare_frequency_deviation(base_frequency, comparison_frequency):
         for character, frequency in base_frequency.items()
     ) / len(base_frequency)
 
+with open('sample.txt','r') as sample_file:
+    sample_text = sample_file.read()
+
+SAMPLE_FREQUENCIES = get_character_frequencies(sample_text)
+
 class Set1Challenge1Tests(unittest.TestCase):
     def test_converts_hex_to_base64(self):
         expected = 'SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t\n'
@@ -45,11 +50,6 @@ class Set1Challenge2Tests(unittest.TestCase):
 
 class Set1Challenge3Tests(unittest.TestCase):
     def test_gets_message(self):
-        with open('sample.txt','r') as sample_file:
-            sample_text = sample_file.read()
-
-        sample_frequencies = get_character_frequencies(sample_text)
-
         xored_string = bytes.fromhex('1b37373331363f78151b7f2b783431333d78397828372d363c78373e783a393b3736')
 
         lowest_frequency_deviation_string = None
@@ -60,7 +60,7 @@ class Set1Challenge3Tests(unittest.TestCase):
             key = bytes([i]) * len(xored_string)
             try_string = xor_bytes(xored_string, key).decode('utf-8')
             try_string_frequency_deviation = compare_frequency_deviation(
-                sample_frequencies,
+                SAMPLE_FREQUENCIES,
                 get_character_frequencies(try_string),
             )
 
@@ -74,5 +74,39 @@ class Set1Challenge3Tests(unittest.TestCase):
 
         self.assertEqual(expected, actual)
 
+class Set1Challenge4Tests(unittest.TestCase):
+    def test_gets_message(self):
+        with open('set1challenge4.txt','r') as f:
+            lines = f.readlines()
+
+
+        lowest_frequency_deviation_string = None
+        lowest_frequency_deviation = None
+
+        for line in lines:
+            line_bytes = bytes.fromhex(line)
+
+            for i in range(128):
+                key_char = bytes([i]).decode('utf-8')
+                key = bytes([i]) * len(line_bytes)
+
+                try:
+                    try_string = xor_bytes(line_bytes, key).decode('utf-8')
+                    try_string_frequency_deviation = compare_frequency_deviation(
+                        SAMPLE_FREQUENCIES,
+                        get_character_frequencies(try_string),
+                    )
+
+                    if lowest_frequency_deviation is None or try_string_frequency_deviation < lowest_frequency_deviation:
+                        lowest_frequency_deviation_string = try_string
+                        lowest_frequency_deviation = try_string_frequency_deviation
+                except:
+                    pass
+
+        expected = 'Now that the party is jumping\n'
+        actual = lowest_frequency_deviation_string
+
+        self.assertEqual(expected, actual)
+
 if __name__ == '__main__':
     unittest.main()