diff --git a/core/src/main/java/com/muwire/core/SharedFile.java b/core/src/main/java/com/muwire/core/SharedFile.java
index 5813c133..7be6e7fd 100644
--- a/core/src/main/java/com/muwire/core/SharedFile.java
+++ b/core/src/main/java/com/muwire/core/SharedFile.java
@@ -20,6 +20,7 @@ public class SharedFile {
 
     private final File file;
     private final byte[] root;
+    private final InfoHash rootInfoHash;
     private final int pieceSize;
 
     private final String cachedPath;
@@ -37,6 +38,7 @@ public class SharedFile {
     public SharedFile(File file, byte[] root, int pieceSize) throws IOException {
         this.file = file;
         this.root = root;
+        this.rootInfoHash = new InfoHash(root);
         this.pieceSize = pieceSize;
         this.cachedPath = file.getAbsolutePath();
         this.cachedLength = file.length();
@@ -64,6 +66,8 @@ public class SharedFile {
         return root;
     }
 
+    public InfoHash getRootInfoHash() {return rootInfoHash;}
+
     public int getPieceSize() {
         return pieceSize;
     }
diff --git a/gui/griffon-app/views/com/muwire/gui/MainFrameView.groovy b/gui/griffon-app/views/com/muwire/gui/MainFrameView.groovy
index fc774634..32df64b6 100644
--- a/gui/griffon-app/views/com/muwire/gui/MainFrameView.groovy
+++ b/gui/griffon-app/views/com/muwire/gui/MainFrameView.groovy
@@ -361,7 +361,7 @@ class MainFrameView {
                                                     closureColumn(header : trans("COMMENTS"), preferredWidth : 50, type : Boolean, read : {it.getComment() != null})
                                                     closureColumn(header : trans("CERTIFIED"), preferredWidth : 50, type : Boolean, read : {
                                                         Core core = application.context.get("core")
-                                                        core.certificateManager.hasLocalCertificate(new InfoHash(it.getRoot()))
+                                                        core.certificateManager.hasLocalCertificate(it.getRootInfoHash())
                                                     })
                                                     closureColumn(header : trans("PUBLISHED"), preferredWidth : 50, type : Boolean, read : {row -> row.isPublished()})
                                                     closureColumn(header : trans("SEARCH_HITS"), preferredWidth: 50, type : Integer, read : {it.getHits()})