diff -r b9f6f8606065 -r c9d3ea14d270 src/java.base/share/classes/sun/security/util/ArrayUtil.java
--- a/src/java.base/share/classes/sun/security/util/ArrayUtil.java	Fri Aug 17 13:40:17 2018 -0400
+++ b/src/java.base/share/classes/sun/security/util/ArrayUtil.java	Fri Aug 17 14:37:01 2018 -0400
@@ -32,7 +32,7 @@
 
 
 /**
- * This class holds the various utility methods for array range checks.
+ * This class holds the various utility methods for arrays.
  */
 
 public final class ArrayUtil {
@@ -52,4 +52,22 @@
         // NPE is thrown when array is null
         Preconditions.checkFromIndexSize(offset, len, array.length, AIOOBE_SUPPLIER);
     }
+
+
+    private static void swap(byte[] arr, int i, int j) {
+        byte tmp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = tmp;
+    }
+
+    public static void reverse(byte [] arr) {
+        int i = 0;
+        int j = arr.length - 1;
+
+        while (i < j) {
+            swap(arr, i, j);
+            i++;
+            j--;
+        }
+    }
 }