diff --git a/aes.c b/aes.c
index 42eca9e..4870670 100644
--- a/aes.c
+++ b/aes.c
@@ -9,7 +9,7 @@
 #define MUL(x,y) aes_GaloisFieldMultiply((x),(y))
 #define MUL2(x)  (((x) << 1) ^ (0x1B & (((x) >> 7) * 0xFF))) & 0xFF
 #define MUL3(x)  ((x) ^ MUL2(x))
-#define SUB4(x)  ((s_box[((x) & 0xFF000000) >> 24] << 24) | (s_box[((x) & 0xFF0000) >> 16] << 16) | (s_box[((x) & 0xFF00) >> 8] << 8) | s_box[((x) & 0xFF)])
+
 
 // AES Tables
 
@@ -65,6 +65,13 @@ void aes_InvMixColumns (uint8_t state[16]);
 void aes_AddRoundKey   (uint8_t state[16], uint8_t sub_key[16]);
 
 // Maths Operation Definitions
+void sub4(uint8_t * t)
+{
+	t[0]=s_box[t[0]];
+	t[1]=s_box[t[1]];
+	t[2]=s_box[t[2]];
+	t[3]=s_box[t[3]];
+}
 
 uint8_t aes_GaloisFieldMultiply (uint8_t fixed, uint8_t variable);
 
@@ -82,10 +89,10 @@ void aes_init(uint32_t *round_key, counter b, uint32_t *key, counter n)
       cycle = 0;
 
       aes_Rotate((uint8_t *) &t);
-      t = SUB4(t);
+      sub4((uint8_t *)&t);
       ((uint8_t *) &t)[0] ^= rcon[i++];
     } else if (cycle == 4 && n == 8) {
-      t = SUB4(t);
+      sub4((uint8_t *)&t);
     }
 
     t ^= round_key[position - n];
diff --git a/test/test.py b/test/test.py
index 931b984..270034d 100644
--- a/test/test.py
+++ b/test/test.py
@@ -41,19 +41,22 @@ def test_file(file_path, size):
 
     command += " -s " + str(size)
 
+    print ("Running command: "+command);
     output = subprocess.check_output(command, shell=True).strip()
+    output =  str(output).strip('b').strip("'");
+
 
     if decrypt:
         if output.upper() != plainText.upper():
-            print 'Failed decrypting {} to {}'.format(cipherText, plainText.upper())
-            print "Got: {}".format(output.upper())
-            print "Key: {}".format(key)
+            print ('Failed decrypting '+ cipherText+ ' to ' + plainText.upper())
+            print ("Got: ",output.upper())
+            print ("Key: ",key)
             sys.exit(1)
     else:
         if output.upper() is not cipherText.upper():
-            print 'Failed encrypting {} to {}'.format(plainText, cipherText.upper())
-            print "Got: {}".format(output.upper())
-            print "Key: {}".format(key)
+            print ('Failed encrypting '+plainText+' to '+cipherText.upper())
+            print ("Got: ",output.upper())
+            print ("Key: ",key)
             sys.exit(1)
 
     tests = tests + 1
@@ -73,4 +76,4 @@ def test_file(file_path, size):
     test_file(files[2][0], 128)
     test_file(files[2][1], 128)
     test_file(files[2][2], 128)
-    print "{} have passed successfully".format(tests)
+    print (str(tests) + " have passed successfully")