diff --git a/pg/src/main/java/org/bouncycastle/openpgp/PGPSignature.java b/pg/src/main/java/org/bouncycastle/openpgp/PGPSignature.java
index fc2c3d1515..b5060ef848 100644
--- a/pg/src/main/java/org/bouncycastle/openpgp/PGPSignature.java
+++ b/pg/src/main/java/org/bouncycastle/openpgp/PGPSignature.java
@@ -191,10 +191,18 @@ private void checkSaltSize()
     }
 
     private void updateWithSalt()
+            throws PGPException
     {
         if (getVersion() == SignaturePacket.VERSION_6)
         {
-            update(sigPck.getSalt());
+            try
+            {
+                sigOut.write(sigPck.getSalt());
+            }
+            catch (IOException e)
+            {
+                throw new PGPException("Cannot update signature with salt.", e);
+            }
         }
     }