@@ -22,10 +22,17 @@
 #define TAGGED_POINTER_BITS 4
 #define NUM_TAGGED_POINTER_CLASSES (1 << (TAGGED_POINTER_BITS - 1))
 
 Class objc_tagged_pointer_classes[NUM_TAGGED_POINTER_CLASSES];
 static int taggedPointerClassesCount;
+uintptr_t objc_tagged_pointer_secret;
+
+void
+objc_setTaggedPointerSecret(uintptr_t secret)
+{
+	objc_tagged_pointer_secret = secret & ~(uintptr_t)1;
+}
 
 int
 objc_registerTaggedPointerClass(Class class)
 {
 	int i;
@@ -46,11 +53,11 @@
 }
 
 Class
 object_getTaggedPointerClass(id object)
 {
-	uintptr_t pointer = (uintptr_t)object;
+	uintptr_t pointer = (uintptr_t)object ^ objc_tagged_pointer_secret;
 
 	pointer &= (1 << TAGGED_POINTER_BITS) - 1;
 	pointer >>= 1;
 
 	if (pointer >= NUM_TAGGED_POINTER_CLASSES)
@@ -60,11 +67,11 @@
 }
 
 uintptr_t
 object_getTaggedPointerValue(id object)
 {
-	uintptr_t pointer = (uintptr_t)object;
+	uintptr_t pointer = (uintptr_t)object ^ objc_tagged_pointer_secret;
 
 	pointer >>= TAGGED_POINTER_BITS;
 
 	return pointer;
 }
@@ -81,7 +88,7 @@
 		return nil;
 
 	pointer = (class << 1) | 1;
 	pointer |= (value << TAGGED_POINTER_BITS);
 
-	return (id)pointer;
+	return (id)(pointer ^ objc_tagged_pointer_secret);
 }