diff --git a/hadoop-common-project/hadoop-common/CHANGES.txt b/hadoop-common-project/hadoop-common/CHANGES.txt
index f5a260c25cb..38cc8104ade 100644
--- a/hadoop-common-project/hadoop-common/CHANGES.txt
+++ b/hadoop-common-project/hadoop-common/CHANGES.txt
@@ -135,6 +135,9 @@ Release 2.6.0 - UNRELEASED
     HADOOP-10769. Create KeyProvider extension to handle delegation tokens.
     (Arun Suresh via atm)
 
+    HADOOP-10812. Delegate KeyProviderExtension#toString to underlying
+    KeyProvider. (wang)
+
   BUG FIXES
 
     HADOOP-10781. Unportable getgrouplist() usage breaks FreeBSD (Dmitry
diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProviderExtension.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProviderExtension.java
index d5ba8ba6337..3b1eb582aba 100644
--- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProviderExtension.java
+++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/crypto/key/KeyProviderExtension.java
@@ -120,4 +120,9 @@ public abstract class KeyProviderExtension
   public void flush() throws IOException {
     keyProvider.flush();
   }
+
+  @Override
+  public String toString() {
+    return getClass().getSimpleName() + ": " + keyProvider.toString();
+  }
 }