diff --git a/src/main/java/com/sunyard/sge/database/SydApi.java b/src/main/java/com/sunyard/sge/database/SydApi.java
index a916767..9bf698c 100644
--- a/src/main/java/com/sunyard/sge/database/SydApi.java
+++ b/src/main/java/com/sunyard/sge/database/SydApi.java
@@ -272,7 +272,7 @@ public interface SydApi {
     );
 
 
-    public SydApiSM4 initSM4(SydApi sydApi, int iKeyIndex, int ende);
+    public SydApiSM4 initSM4( int iKeyIndex, int ende);
 
     public SydApiSM3 initSM3();
 
diff --git a/src/main/java/com/sunyard/sge/database/SydApi4Database.java b/src/main/java/com/sunyard/sge/database/SydApi4Database.java
index 43e3998..a4f3d2e 100644
--- a/src/main/java/com/sunyard/sge/database/SydApi4Database.java
+++ b/src/main/java/com/sunyard/sge/database/SydApi4Database.java
@@ -768,7 +768,7 @@ public class SydApi4Database implements SydApi {
 
 
     @Override
-    public SydApiSM4 initSM4(SydApi sydApi, int iKeyIndex, int ende) {
+    public SydApiSM4 initSM4(int iKeyIndex, int ende) {
 
         return new SydApiSM4(this,iKeyIndex,ende);
     }
diff --git a/src/main/java/com/sunyard/sge/database/SydApiSM4.java b/src/main/java/com/sunyard/sge/database/SydApiSM4.java
index caa62b2..13384be 100644
--- a/src/main/java/com/sunyard/sge/database/SydApiSM4.java
+++ b/src/main/java/com/sunyard/sge/database/SydApiSM4.java
@@ -21,10 +21,10 @@ public class SydApiSM4 {
         this.iKeyIndex = iKeyIndex;
     }
 
-    public void update(byte[] pcData) {
+    public byte[] update(byte[] pcData) {
         this.pcdataResult = pcData;
         if (null == pcData || pcData.length == 0) {
-            return;
+            return new byte[0];
         }
         int plength = pcData.length;
         if (is_finished) {
@@ -58,20 +58,22 @@ public class SydApiSM4 {
                 bufferResult.put(bytes1);
                 sourceWrap = bufferResult;
             }
-            byte[] bytes = api.SYD_SM4_LongData(iKeyIndex, pcdataResult, iPkgNum, iFlag);
-            iPkgNum = 2;
+             iPkgNum = 2;
+             return api.SYD_SM4_LongData(iKeyIndex, pcdataResult, iPkgNum, iFlag);
+
         } else {
             if (16 > pcData.length + sourceWrap.array().length) {
                 ByteBuffer bufferResult = ByteBuffer.allocate(sourceWrap.array().length + plength);
                 bufferResult.put(SydSM4Mac.bytebuffer2ByteArray(sourceWrap));
                 bufferResult.put(pcData);
                 sourceWrap = bufferResult;
+                return new byte[0];
             } else if ((pcData.length + sourceWrap.array().length) % 16 == 0) {
                 ByteBuffer bufferResult = ByteBuffer.allocate(sourceWrap.array().length + plength);
                 bufferResult.put(SydSM4Mac.bytebuffer2ByteArray(sourceWrap));
                 bufferResult.put(pcData);
                 byte[] bytes = SydSM4Mac.bytebuffer2ByteArray(bufferResult);
-                api.SYD_SM4_LongData(iKeyIndex, bytes, iPkgNum, iFlag);
+                return api.SYD_SM4_LongData(iKeyIndex, bytes, iPkgNum, iFlag);
             } else {
                 ByteBuffer bufferResult = ByteBuffer.allocate(sourceWrap.array().length + plength);
                 bufferResult.put(SydSM4Mac.bytebuffer2ByteArray(sourceWrap));
@@ -88,8 +90,8 @@ public class SydApiSM4 {
                 ByteBuffer bufferResults = ByteBuffer.allocate(remainder);
                 bufferResults.put(bytes1);
                 sourceWrap = bufferResults;
-                api.SYD_SM4_LongData(iKeyIndex, pcdataResult, iPkgNum, iFlag);
                 iPkgNum = 2;
+                return  api.SYD_SM4_LongData(iKeyIndex, pcdataResult, iPkgNum, iFlag);
             }
         }
     }
diff --git a/src/test/java/test/LongDataTest.java b/src/test/java/test/LongDataTest.java
index f32ea42..0b4ed09 100644
--- a/src/test/java/test/LongDataTest.java
+++ b/src/test/java/test/LongDataTest.java
@@ -99,7 +99,7 @@ public class LongDataTest {
             int lucky = new Random().nextInt(4065);
             byte[] data = new byte[lucky];
             System.out.println("len="+lucky);
-            new Random().nextBytes( data );
+//            new Random().nextBytes( data );
             sydApiMac.update(data);
         }
 
@@ -113,7 +113,7 @@ public class LongDataTest {
 
     @Test
     public void case5(){
-        SydApiSM4 sydApiSM4 = api.initSM4(api, 1,1);
+        SydApiSM4 sydApiSM4 = api.initSM4(1,1);
         byte[] enData = sydApiSM4.finish();
         System.out.println(Util.bytes2HexString( enData ) );
         Assert.assertArrayEquals( Util.hexString2Bytes("FF49F76AD3A71651FE1A8A9F0D2A689E"), enData );
@@ -121,7 +121,7 @@ public class LongDataTest {
 
     @Test
     public void case6(){
-        SydApiSM4 sydApiSM4 = api.initSM4(api, 1,1);
+        SydApiSM4 sydApiSM4 = api.initSM4(1,1);
 
         for (int i =0 ; i < 10; i ++) {
             int lucky = new Random().nextInt(4065);
@@ -136,6 +136,22 @@ public class LongDataTest {
         System.out.println(Util.bytes2HexString( enData ) );
     }
 
+    @Test
+    public void case12(){
+        for (int i =0 ; i < 1000; i ++) {
+            int lucky = new Random().nextInt(4065);
+            SydApiSM4 sydApiSM4 = api.initSM4( 1,1);
+            byte[] bytes = new byte[lucky];
+            sydApiSM4.update(new byte[lucky]);
+            byte[] finish = sydApiSM4.finish();
+            SydApiSM4 sydApiSM42 = api.initSM4(1,0);
+            sydApiSM42.update(finish);
+            byte[] finish1 = sydApiSM42.finish();
+            System.out.println("原始数据："+Arrays.toString(bytes)+",\n"+"解密后数据："+Arrays.toString(finish1));
+
+        }
+
+    }
 
 
 }