Index: java/org/apache/catalina/realm/RealmBase.java
===================================================================
--- java/org/apache/catalina/realm/RealmBase.java       (revision 1303279)
+++ java/org/apache/catalina/realm/RealmBase.java       (working copy)
@@ -381,7 +381,7 @@
                                   String qop, String realm,
                                   String md5a2) {

-        String md5a1 = getDigest(username, realm);
+        String md5a1 = getDigest(username, realm).toLowerCase();
         if (md5a1 == null)
             return null;
         String serverDigestValue;