parallelize attack

main.py

@@ -98,10 +98,14 @@ def gen_6_bytes(key=[randint(0, 1) for _ in range(40)]):
     cipher = css_encrypt(text, key)
     return cipher
 
-def attack(Bytes=gen_6_bytes()):
+import multiprocessing
+
+def attack_worker(start, end, Bytes, result_queue, stop_event):
     taps17 = [0, 14]
     taps25 = [0, 3, 4, 12]
-    for i in range((2**16)-1):
+    for i in range(start, end):
+        if stop_event.is_set():
+            return
         lfsr17_init = [int(bit) for bit in bin(i)[2:].zfill(16)]+[1]
         lfsr17 = lfsr(lfsr17_init, taps17)
         x = []
@@ -134,17 +138,46 @@ def attack(Bytes=gen_6_bytes()):
         c=1 if x[4]+y[4]>255 else 0
         z6 = (x[5]+y[5]+c)%256
         if z4 == Bytes[3] and z5 == Bytes[4] and z6 == Bytes[5]:
-            print("key found: ", end='\t')
             key = bin(x[0])[2:].zfill(8)[::-1] + bin(x[1])[2:].zfill(8)[::-1] + bin(y[0])[2:].zfill(8)[::-1] + bin(y[1])[2:].zfill(8)[::-1] + bin(y[2])[2:].zfill(8)[::-1]
-            print(key)
-            return [int(bit) for bit in key]
-            break
+            result_queue.put(key)
+            stop_event.set()
+            return
+
+def attack(Bytes=gen_6_bytes()):
+    result_queue = multiprocessing.Queue()
+    stop_event = multiprocessing.Event()
+    processes = []
+    num_cores = multiprocessing.cpu_count()
+    max_upper_limit = 2**16
+    chunk_size = max_upper_limit // num_cores
+
+    for i in range(num_cores):
+        start = i * chunk_size
+        end = start + chunk_size
+        process = multiprocessing.Process(target=attack_worker, args=(start, end, Bytes, result_queue, stop_event))
+        processes.append(process)
+        process.start()
+    # # last process
+    # start = (num_cores-1) * chunk_size
+    # end = max_upper_limit
+    # process = multiprocessing.Process(target=attack_worker, args=(start, end, Bytes, result_queue, stop_event))
+    # processes.append(process)
+    # process.start()
+
+    for process in processes:
+        process.join()
+
+    while not result_queue.empty():
+        key = result_queue.get()
+        print(f'key found: \t{key}')
+        return [int(bit) for bit in key]
 
 def test_attack(n=1):
     success = 0
     print(f'testing attack in 2^16 against CSS {n} times (keys randomly generated each time)\n')
     for _ in range(n):
         key = [randint(0, 1) for _ in range(40)]
+        # key = [1]*40
         key_string = ''.join(str(bit) for bit in key)
         print(f'key generated: \t{key_string}')
         Bytes = gen_6_bytes(key)
@@ -159,5 +192,4 @@ test_lfsr17()
 print()
 test_encrypt()
 print()
-#gen_6_bytes()
-test_attack(100)
+test_attack(5)