diff --git a/src/main/java/com/sunyard/sge/database/SydApiSM4.java b/src/main/java/com/sunyard/sge/database/SydApiSM4.java
index 36db984..0d385a1 100644
--- a/src/main/java/com/sunyard/sge/database/SydApiSM4.java
+++ b/src/main/java/com/sunyard/sge/database/SydApiSM4.java
@@ -14,7 +14,7 @@ public class SydApiSM4 {
     private boolean is_finished = false;
     private byte[] dataResult = new byte[0];
 
-    ByteBuffer sourceWrap = ByteBuffer.wrap(new byte[0]);
+    ByteBuffer sourceWrap = ByteBuffer.wrap(new byte[1]);
 
 
     public SydApiSM4(SydApi api, int iKeyIndex, int endeFlag) {