diff --git a/src/ooxml/testcases/org/apache/poi/ss/extractor/TestEmbeddedExtractor.java b/src/ooxml/testcases/org/apache/poi/ss/extractor/TestEmbeddedExtractor.java
index 0b755b91d6e..cb018656e16 100644
--- a/src/ooxml/testcases/org/apache/poi/ss/extractor/TestEmbeddedExtractor.java
+++ b/src/ooxml/testcases/org/apache/poi/ss/extractor/TestEmbeddedExtractor.java
@@ -106,6 +106,7 @@ public void extractFromXSSF() throws IOException, EncryptedDocumentException, In
 
     public static String md5hash(byte[] input) {
         try {
+           /** Note to user MD5 is not secure, recommend "SHA-512" */
             MessageDigest md = MessageDigest.getInstance("MD5");
             byte[] hash = md.digest(input);
             return Base64.getEncoder().encodeToString(hash);