diff --git a/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java b/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java
index 2f35344..d27fcb9 100644
--- a/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java
+++ b/src/main/java/cc/baka9/catseedlogin/util/CommunicationAuth.java
@@ -9,7 +9,7 @@ public class CommunicationAuth {
 
     static {
         try {
-            messageDigest = MessageDigest.getInstance("MD5");
+            messageDigest = MessageDigest.getInstance("SHA-256");
         } catch (NoSuchAlgorithmException e) {
             throw new RuntimeException(e);
         }