Initial commit

lab3-hash-function/app/modes/test_collisions.py

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+import itertools
+import string
+from modes.hash_mode import HashMode
+
+
+class CollisionsTest:
+    """
+    Грубый поиск коллизий: перебираем строки до max_len
+    из заданного алфавита и проверяем, совпадут ли хэши.
+    """
+
+    def run(self, variant: str, max_len: int = 3, alphabet: str = "alnum", bytes: int = 16) -> dict:
+        hasher = HashMode()
+        seen = {}
+
+        # выбор алфавита
+        if alphabet == "alnum":
+            chars = string.ascii_lowercase + string.digits
+        elif alphabet == "alpha":
+            chars = string.ascii_lowercase
+        elif alphabet == "digits":
+            chars = string.digits
+        else:
+            raise ValueError(f"Неизвестный алфавит: {alphabet}")
+
+        for length in range(1, max_len + 1):
+            for msg_tuple in itertools.product(chars, repeat=length):
+                msg = "".join(msg_tuple)
+                h = hasher.run(variant, msg, bytes=bytes)
+                if h in seen:
+                    return {
+                        "collision_found": True,
+                        "hash": h,
+                        "messages": [seen[h], msg],
+                    }
+                seen[h] = msg
+
+        return {"collision_found": False}