1 files changed, 16 insertions, 0 deletions
diff --git a/crypto/src/util/Integers.cs b/crypto/src/util/Integers.cs
index 7d98de586..b243b88b2 100644
--- a/crypto/src/util/Integers.cs
+++ b/crypto/src/util/Integers.cs
@@ -1,5 +1,7 @@
 using System;
 
+using Org.BouncyCastle.Math.Raw;
+
 namespace Org.BouncyCastle.Utilities
 {
     public abstract class Integers
@@ -29,6 +31,20 @@ namespace Org.BouncyCastle.Utilities
             return DeBruijnTZ[(uint)((i & -i) * 0x04D7651F) >> 27];
         }
 
+        public static int Reverse(int i)
+        {
+            i = (int)Bits.BitPermuteStepSimple((uint)i, 0x55555555U, 1);
+            i = (int)Bits.BitPermuteStepSimple((uint)i, 0x33333333U, 2);
+            i = (int)Bits.BitPermuteStepSimple((uint)i, 0x0F0F0F0FU, 4);
+            return ReverseBytes(i);
+        }
+
+        public static int ReverseBytes(int i)
+        {
+            return RotateLeft((int)((uint)i & 0xFF00FF00U),  8) |
+                   RotateLeft((int)((uint)i & 0x00FF00FFU), 24);
+        }
+
         public static int RotateLeft(int i, int distance)
         {
             return (i << distance) ^ (int)((uint)i >> -distance);