BJA-450 extra optimisation

1 files changed, 23 insertions, 5 deletions

diff --git a/src/main/java/org/bouncycastle/crypto/macs/HMac.java b/src/main/java/org/bouncycastle/crypto/macs/HMac.java
index e9f070f9..d4345d9b 100644
--- a/src/main/java/org/bouncycastle/crypto/macs/HMac.java
+++ b/src/main/java/org/bouncycastle/crypto/macs/HMac.java
@@ -24,7 +24,8 @@ public class HMac
     private Digest digest;
     private int digestSize;
     private int blockLength;
-    private Memoable savedState;
+    private Memoable ipadState;
+    private Memoable opadState;
 
     private byte[] inputPad;
     private byte[] outputBuf;
@@ -135,11 +136,18 @@ public class HMac
         xorPad(inputPad, blockLength, IPAD);
         xorPad(outputBuf, blockLength, OPAD);
 
+        if (digest instanceof Memoable)
+        {
+            opadState = ((Memoable)digest).copy();
+
+            ((Digest)opadState).update(outputBuf, 0, blockLength);
+        }
+
         digest.update(inputPad, 0, inputPad.length);
 
         if (digest instanceof Memoable)
         {
-            savedState = ((Memoable)digest).copy();
+            ipadState = ((Memoable)digest).copy();
         }
     }
 
@@ -167,7 +175,17 @@ public class HMac
         int outOff)
     {
         digest.doFinal(outputBuf, blockLength);
-        digest.update(outputBuf, 0, outputBuf.length);
+
+        if (opadState != null)
+        {
+            ((Memoable)digest).reset(opadState);
+            digest.update(outputBuf, blockLength, digest.getDigestSize());
+        }
+        else
+        {
+            digest.update(outputBuf, 0, outputBuf.length);
+        }
+
         int len = digest.doFinal(out, outOff);
 
         for (int i = blockLength; i < outputBuf.length; i++)
@@ -175,9 +193,9 @@ public class HMac
             outputBuf[i] = 0;
         }
 
-        if (savedState != null)
+        if (ipadState != null)
         {
-            ((Memoable)digest).reset(savedState);
+            ((Memoable)digest).reset(ipadState);
         }
         else
         {