diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index 4136e40acf..a389b1b0b0 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -830,6 +830,10 @@ Release 2.1.0-beta - 2013-07-02
     HADOOP-8440. HarFileSystem.decodeHarURI fails for URIs whose host contains
     numbers. (Ivan Mitic via cnauroth)
 
+    HADOOP-9643. org.apache.hadoop.security.SecurityUtil calls 
+    toUpperCase(Locale.getDefault()) as well as toLowerCase(Locale.getDefault()) 
+    on hadoop.security.authentication value. (markrmiller@gmail.com via tucu)
+
 Release 2.0.5-alpha - 06/06/2013
 
   INCOMPATIBLE CHANGES
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
index b6bd06af39..416a442f12 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/SecurityUtil.java
@@ -672,7 +672,7 @@ public class SecurityUtil {
   public static AuthenticationMethod getAuthenticationMethod(Configuration conf) {
     String value = conf.get(HADOOP_SECURITY_AUTHENTICATION, "simple");
     try {
-      return Enum.valueOf(AuthenticationMethod.class, value.toUpperCase());
+      return Enum.valueOf(AuthenticationMethod.class, value.toUpperCase(Locale.ENGLISH));
     } catch (IllegalArgumentException iae) {
       throw new IllegalArgumentException("Invalid attribute value for " +
           HADOOP_SECURITY_AUTHENTICATION + " of " + value);
@@ -685,6 +685,6 @@ public class SecurityUtil {
       authenticationMethod = AuthenticationMethod.SIMPLE;
     }
     conf.set(HADOOP_SECURITY_AUTHENTICATION,
-             authenticationMethod.toString().toLowerCase());
+             authenticationMethod.toString().toLowerCase(Locale.ENGLISH));
   }
 }