diff --git a/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/authentication/DigestMD5Authenticator.java b/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/authentication/DigestMD5Authenticator.java
index 5784ec3..0272b24 100644
--- a/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/authentication/DigestMD5Authenticator.java
+++ b/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/authentication/DigestMD5Authenticator.java
@@ -272,7 +272,7 @@
             digest.update(authString.getBytes("US-ASCII"));
 
             // this gets added on to the client response
-            String responseString = clientResponse + new String(Hex.encode(digest.digest()), "US_ASCII");
+            String responseString = clientResponse + new String(Hex.encode(digest.digest()), "US-ASCII");
             // and this gets fed back into the digest
             digest.update(responseString.getBytes("US-ASCII"));
 
diff --git a/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/pop3/connection/POP3Connection.java b/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/pop3/connection/POP3Connection.java
index 8e854b0..aa33ed7 100644
--- a/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/pop3/connection/POP3Connection.java
+++ b/geronimo-javamail_1.4/geronimo-javamail_1.4_provider/src/main/java/org/apache/geronimo/javamail/store/pop3/connection/POP3Connection.java
@@ -632,7 +632,7 @@
                 byte[] challenge = response.decodeChallengeResponse();
 
                 try {
-                    String responseString = new String(Base64.encode(authenticator.evaluateChallenge(challenge)), "US_ASCII");
+                    String responseString = new String(Base64.encode(authenticator.evaluateChallenge(challenge)), "US-ASCII");
 
                     // have the authenticator evaluate and send back the encoded response.
                     response = sendCommand(responseString);