实现“实现对签名推式包的替换编码

src/main/java/security/KeyChain.java

@@ -3,8 +3,10 @@ package security;
 import component.Signature;
 import encoding.Block;
 import encoding.SelfEncodingBase;
+import minsecurity.crypto.AsymKeyException;
 import minsecurity.identity.Identity;
 import minsecurity.identity.IdentityException;
+import org.bouncycastle.crypto.CryptoException;
 import packet.CPacket;
 import packet.Data;
 import packet.Interest;
@@ -16,6 +18,7 @@ import javax.crypto.NoSuchPaddingException;
 import java.security.InvalidKeyException;
 import java.security.NoSuchAlgorithmException;
 import java.security.NoSuchProviderException;
+import java.util.Arrays;
 
 /*
  * @Author: hongyu guo
@@ -260,6 +263,25 @@ public class KeyChain {
         this.sign(data.minPacket);
     }
 
+    /**
+     * 对已经合并好的标识区和只读区进行签名
+     * @param mergeArray 原文：已经合并好的标识区和只读区
+     * @return 密文
+     */
+    public byte[] signBytes(byte[] mergeArray) throws Exception {
+        return this.currentIdentity.sign(mergeArray);
+    }
+
+    /**
+     * 验证签名
+     * @param mergeArray 原文
+     * @param digest 密文
+     * @return
+     */
+    public boolean verifyBytes(byte[] mergeArray,byte[] digest) throws Exception {
+        return this.currentIdentity.verify(mergeArray,digest);
+    }
+
     /**
      * 验证一个MIN网络包中的签名是否有效
      * @param minPacket

src/test/java/mgmt/RegisterPrefixHelperTest.java

@@ -31,10 +31,10 @@ public class RegisterPrefixHelperTest {
         // 初始化KeyChain
 //        KeyChain keyChain=new KeyChain();
 
-        RegisterPrefixHelper helper=new RegisterPrefixHelper();
+//        RegisterPrefixHelper helper=new RegisterPrefixHelper();
         KeyManagerExample.INSTANCE.initKeyChain("/wefree/test","D://");
         face.setKeyChain(KeyManagerExample.INSTANCE.getKeyChain());
-        helper.registerPrefix(identifier,face,KeyManagerExample.INSTANCE.getKeyChain());
+//        helper.registerPrefix(identifier,face,KeyManagerExample.INSTANCE.getKeyChain());
 
         // 测试发包速率
         Identifier serverIden = null;

src/test/java/testPrivate.java

@@ -1,5 +1,16 @@
+import component.ComponentException;
+import component.Identifier;
+import encoding.TLV;
+import encoding.TLVException;
+import encoding.VlInt;
+import encoding.VlIntException;
 import minsecurity.crypto.sm2.SM2KeyPair;
 import org.bouncycastle.pqc.math.linearalgebra.ByteUtils;
+import packet.CPacket;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+import java.util.Random;
 
 /*
  * @Author: hongyu guo
@@ -17,4 +28,160 @@ public class testPrivate {
         System.out.println("a = " + a);
         System.out.println("private key = " + ByteUtils.toHexString(sm2KeyPair.getSm2PrivateKey().getBytes()));
     }
+
+    public static String getFixLenthString(int strLength) {
+        Random rm = new Random();
+        // 获得随机数
+        double pross = (1 + rm.nextDouble()) * Math.pow(10, strLength);
+        // 将获得的获得随机数转化为字符串
+        String fixLenthString = String.valueOf(pross);
+        // 返回固定的长度的随机数
+        return fixLenthString.substring(1, strLength + 1);
+    }
+
+    public static String getAll0String() {
+        return new String("0000000000");
+    }
+
+    public static void main(String[] args) throws VlIntException {
+        // 测试vlint
+        VlInt a=new VlInt(1200);
+        System.out.println("1200 is bytes: "+ Arrays.toString(a.getVlIntBytes()));
+        System.out.println("1200 len: "+a.size());
+        a=new VlInt(1204);
+        System.out.println("1204 is bytes: "+ Arrays.toString(a.getVlIntBytes()));
+        System.out.println("1204 len: "+a.size());
+        a=new VlInt(1298);
+        System.out.println("1298 is bytes: "+ Arrays.toString(a.getVlIntBytes()));
+        System.out.println("1298 len: "+a.size());
+
+        byte[] matchArray=new byte[]{(byte)11,(byte) 0,(byte) 48,(byte) 48,(byte) 48,(byte) 48,(byte) 48};
+        System.out.println(Arrays.toString(matchArray));
+        System.out.println(findThePos(matchArray));
+
+        int seq=11;
+        Identifier clientIden = null;
+        try {
+            clientIden=new Identifier("/min/gdcni9/default/"+seq);
+        } catch (ComponentException e) {
+            e.printStackTrace();
+            return;
+        }
+        Identifier serverIden = null;
+        try {
+//            serverIden=new Identifier("/hk/vpnserver/10/"+getFixLenthString(10));
+            serverIden=new Identifier("/hk/vpnserver/10/"+getAll0String());
+        } catch (ComponentException e) {
+            e.printStackTrace();
+            return;
+        }
+        CPacket cPacket=new CPacket();
+        cPacket.setSrcIdentifier(clientIden);
+        cPacket.setDstIdentifier(serverIden);
+        cPacket.ttl.setTtl(64);
+        byte[] pay=new byte[10];
+        cPacket.payload.setValue(pay);
+        cPacket.encodeSelf(); // 先编码！！！减少发包阻塞。
+
+        System.out.println(Arrays.toString(cPacket.getRawData()));
+        System.out.println(cPacket.getRawData().length);
+
+//        byte[] ta=cPacket.getRawData();
+//        System.out.println("ta len: "+ta.length);
+        int pos=findThePos(cPacket.getRawData());
+//        System.out.println("pos: "+pos);
+//        byte[] newData=replaceRandomPos(cPacket.getRawData(),pos);
+//        System.out.println("替换结果: "+ Arrays.toString(newData));
+        byte[] newData=replaceRandomPos(cPacket.getRawData(),pos,pos+10,1200);
+        System.out.println("替换结果: "+ Arrays.toString(newData));
+    }
+
+//    [5, 108,
+//   50, 85, 102, 36,
+//  101, 34, 100, 2, 0, 47,
+// 100, 4, 0, 109, 105, 110, 100, 7, 0, 103,
+//100, 99, 110, 105, 57, 100, 8, 0,
+//100, 101, 102, 97, 117, 108, 116,
+//100, 3, 0, 49, 49, 102, 45, 101, 43,
+//100, 2, 0, 47, 100, 3, 0, 104, 107,
+//100, 10, 0, 118, 112, 110, 115, 101, 114, 118, 101, 114,
+//100, 3, 0, 49, 48,
+//100, 11, 0, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 100, 2, 4, 10, 52, 12, -52, 10, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 53, 5, 55, 3, -44, 1, 64
+    // 要找的字符数组是：100, 11, 0, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48
+    // 分析其特点，找到连续的五个48，且前面依次是11、0，即可。假定是10个连续随机数
+    public static int findThePos(byte[] targetArray){
+        byte[] matchArray=new byte[]{(byte)11,(byte) 0,(byte) 48};
+        System.out.println("target: "+Arrays.toString(targetArray));
+        System.out.println("match: "+ Arrays.toString(matchArray));
+        for (int i = 0; i < (targetArray.length-7); i++) {
+            if((targetArray[i]==matchArray[0])
+                && (targetArray[i+1]==matchArray[1])
+                    && (targetArray[i+2]==matchArray[2])
+                    && (targetArray[i+3]==matchArray[2])
+                    && (targetArray[i+4]==matchArray[2])
+                    && (targetArray[i+5]==matchArray[2])
+                    && (targetArray[i+6]==matchArray[2])){
+                System.out.println("我中了");
+                return i+2;
+            }
+        }
+        return -1;
+    }
+
+    public static byte[] replaceRandomPos(byte[] targetArray,int pos){
+        System.arraycopy(getFixLenthString(10).getBytes(StandardCharsets.UTF_8),0,targetArray,pos,10);
+        return targetArray;
+    }
+
+    public static byte[] replaceRandomPos(byte[] targetArray,int randomPos,int readPos,int payloadLen)
+            throws VlIntException {
+        System.out.println("ttt1");
+        // 先读取原头部的总长度
+        VlInt oldLen;
+        try {
+            oldLen= TLV.readVarNumber(targetArray,new VlInt(1));
+        } catch (TLVException e) {
+            e.printStackTrace();
+            return null;
+        }
+        System.out.println("ttt2");
+        // 计算需要总长度
+        VlInt payLen=new VlInt(payloadLen); // 负载长度
+        VlInt readLen=new VlInt(payloadLen+payLen.size()+1); // 可读区长度
+        VlInt packetLen=new VlInt((readPos-1-oldLen.size())
+                +(readLen.getVlIntValue2Int()+readLen.size()+1)
+                +7);// 通用包长度
+        System.out.println("pk len: "+packetLen);
+        int allLen=(packetLen.getVlIntValue2Int()+packetLen.size()+1)-7-payloadLen; // 总长度
+        System.out.println("ttt3");
+        // 构造最后的返回数组
+        byte[] totalData=new byte[allLen];
+        // 1. 拷贝包头
+        totalData[0]=(byte)5;
+        System.arraycopy(packetLen.getVlIntBytes(),0,totalData,1,packetLen.size());
+        System.out.println("ttt4");
+        // 2. 拷贝随机段之前的数据（固定标识字段）
+        System.arraycopy(targetArray,1+oldLen.size(),totalData,1+packetLen.size(),
+                randomPos-1-oldLen.size());
+        System.out.println("ttt5");
+        System.out.println("readpos: "+readPos);
+        System.out.println("packetLen.size: "+packetLen.size());
+        System.out.println("oldlen.size: "+oldLen.size());
+        // 3. 拷贝随机段（目的标识的活动字段）
+        System.arraycopy(getFixLenthString(10).getBytes(StandardCharsets.UTF_8),
+                0,totalData,randomPos+packetLen.size()-oldLen.size(),10);
+        System.out.println("ttt6");
+        // 4. 拷贝负载区头部
+        totalData[readPos+packetLen.size()-oldLen.size()]=(byte)52;
+        System.arraycopy(readLen.getVlIntBytes(),0,totalData,
+                readPos+packetLen.size()-oldLen.size()+1,readLen.size());
+        totalData[readPos+packetLen.size()-oldLen.size()+1+readLen.size()]=(byte)204;
+        System.arraycopy(payLen.getVlIntBytes(),0,totalData,
+                readPos+packetLen.size()-oldLen.size()+1+readLen.size()+1,payLen.size());
+        System.out.println("ttt7");
+        int newRandomPos=randomPos-oldLen.size()+packetLen.size();
+        System.out.println("pos: "+randomPos);
+        System.out.println("newpos: "+newRandomPos);
+        return totalData;
+    }
 }

src/test/java/testQuickEncodeWithSignature.java

@@ -0,0 +1,314 @@
+import component.ComponentException;
+import component.Identifier;
+import encoding.TLV;
+import encoding.TLVException;
+import encoding.VlInt;
+import encoding.VlIntException;
+import examples.KeyManagerExample;
+import org.bouncycastle.crypto.CryptoException;
+import packet.CPacket;
+
+import java.nio.charset.StandardCharsets;
+import java.util.Arrays;
+
+/*
+ * @Author: Wang Feng
+ * @Description: 测试带签名的打印信息
+ * @Version: 1.0.0
+ * @Date: 11:00 2021/10/28
+ * @Copyright: MIN-Group；国家重大科技基础设施——未来网络北大实验室；深圳市信息论与未来网络重点实验室
+ */
+public class testQuickEncodeWithSignature {
+    public static void main(String[] args){
+        Identifier clientIden = null;
+        try {
+            clientIden=new Identifier("/wefree/test");
+        } catch (ComponentException e) {
+            e.printStackTrace();
+            return;
+        }
+        Identifier serverIden = null;
+        try {
+//            serverIden=new Identifier("/hk/vpnserver/10/"+getFixLenthString(10));
+            serverIden=new Identifier("/hk/vpnserver/10/"+testPrivate.getAll0String());
+        } catch (ComponentException e) {
+            e.printStackTrace();
+            return;
+        }
+        CPacket cPacket=new CPacket();
+        cPacket.setSrcIdentifier(clientIden);
+        cPacket.setDstIdentifier(serverIden);
+        cPacket.ttl.setTtl(64);
+        byte[] pay=new byte[10];
+        cPacket.payload.setValue(pay);
+        cPacket.encodeSelf(); // 先编码！！！减少发包阻塞。
+
+        System.out.println("签名前: "+Arrays.toString(cPacket.getRawData()));
+        System.out.println("签名前len: "+cPacket.getRawData().length);
+
+//        byte[] ta=cPacket.getRawData();
+//        System.out.println("ta len: "+ta.length);
+        int pos=testPrivate.findThePos(cPacket.getRawData());
+        System.out.println("pos: "+pos);
+//        byte[] newData=replaceRandomPos(cPacket.getRawData(),pos);
+//        System.out.println("替换结果: "+ Arrays.toString(newData));
+//        byte[] newData=replaceRandomPos(cPacket.getRawData(),pos,pos+10,1200);
+//        System.out.println("替换结果: "+ Arrays.toString(newData));
+
+        // 签名CPacket
+        KeyManagerExample.INSTANCE.initKeyChain("/wefree/test","D://");
+        try {
+            KeyManagerExample.INSTANCE.getKeyChain().signCPacket(cPacket);
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        cPacket.encodeSelf();
+        // 打印分析签名字段
+        System.out.println("签名后: "+Arrays.toString(cPacket.getRawData()));
+        System.out.println("签名后len: "+cPacket.getRawData().length);
+
+        // 打印带签名的CPacket的标识区
+        byte[] oldIdentifierArea=extractIdentifierArea(cPacket.getRawData());
+        System.out.println("&标识区: "+Arrays.toString(oldIdentifierArea));
+
+        // 更新标识区
+//        byte[] newIdentifierArea=getNewIdentifierArea(oldIdentifierArea);
+//        System.out.println("新标识区："+ Arrays.toString(newIdentifierArea));
+
+        // 提取签名参数区
+        byte[] sigParamsArea=extractSigParamsArea(cPacket.getRawData());
+        System.out.println("&签名参数区："+ Arrays.toString(sigParamsArea));
+
+        // 制造只读区
+        byte[] bytes=new byte[10];
+        byte[] reayonlyArea=genReayonlyArea(bytes);
+        System.out.println("&只读区: "+Arrays.toString(reayonlyArea));
+
+        // 合并标识区和只读区
+        assert oldIdentifierArea != null;
+//        byte[] idenAndReadonly=new byte[oldIdentifierArea.length+reayonlyArea.length];
+//        System.arraycopy(oldIdentifierArea,0,idenAndReadonly,0,oldIdentifierArea.length);
+//        System.arraycopy(reayonlyArea,0,idenAndReadonly,oldIdentifierArea.length,reayonlyArea.length);
+        byte[] idenAndReadonly=mergeIdentityAndReayonly(oldIdentifierArea,reayonlyArea);
+        System.out.println("合并标识区和只读区："+ Arrays.toString(idenAndReadonly));
+        // 计算签名值区的密文
+        byte[] signValueBytes;
+        try {
+            System.out.println("签名名称: "+KeyManagerExample.INSTANCE.getKeyChain().getCurrentIdentity().getName());
+            signValueBytes=KeyManagerExample.INSTANCE.getKeyChain().signBytes(idenAndReadonly);
+        } catch (Exception e) {
+            e.printStackTrace();
+            return;
+        }
+        System.out.println("签名值区的密文: "+ Arrays.toString(signValueBytes));
+        System.out.println("签名值区的密文长度: "+signValueBytes.length);
+        // 验签：由于每次签名的结果（长度和数值）有一定随机性，因此这里使用验签来辩证是否成功签名
+        try {
+            System.out.println("验签结果: "+KeyManagerExample.INSTANCE.getKeyChain().verifyBytes(
+                    idenAndReadonly,signValueBytes));
+        } catch (Exception e) {
+            e.printStackTrace();
+        }
+        // 根据密文构造签名值区
+        byte[] sigValueArea=genSigValueArea(signValueBytes);
+        System.out.println("&签名值区: "+ Arrays.toString(sigValueArea));
+
+        // 构造签名区
+        assert sigParamsArea != null;
+        byte[] sigArea=genSigArea(sigParamsArea,sigValueArea);
+        System.out.println("签名区: "+ Arrays.toString(sigArea));
+
+        // 构造可变区
+        byte[] varDataArea = new byte[]{(byte)53,(byte)5,(byte)55,(byte)3,
+                (byte)212,(byte)1,(byte)64};   // 可变区：TTL字段，TTL为64
+
+        // 构造整个包
+        System.out.println(Arrays.toString(genCPacket(oldIdentifierArea, sigArea, reayonlyArea, varDataArea)));
+    }
+
+    /**
+     *
+     * @param identifierArea 标识区
+     * @param sigArea 签名区
+     * @param reayonlyArea 只读区
+     * @param varDataArea 可变区
+     * @return
+     */
+    public static byte[] genCPacket(byte[] identifierArea,byte[] sigArea,
+                                    byte[] reayonlyArea,byte[] varDataArea){
+        VlInt packetlen=new VlInt(identifierArea.length+sigArea.length
+                        +reayonlyArea.length+varDataArea.length);
+        int allLen;
+        try {
+            allLen=1+packetlen.size()+packetlen.getVlIntValue2Int();
+        } catch (VlIntException e) {
+            e.printStackTrace();
+            return null;
+        }
+        int startIndex=0;
+        byte[] cpacketBytes=new byte[allLen];
+        cpacketBytes[startIndex]=(byte) 5;
+        startIndex++;
+        System.arraycopy(packetlen.getVlIntBytes(),0,cpacketBytes,startIndex,packetlen.size());
+        startIndex+=packetlen.size();
+        System.arraycopy(identifierArea,0,cpacketBytes,startIndex,identifierArea.length);
+        startIndex+=identifierArea.length;
+        System.arraycopy(sigArea,0,cpacketBytes,startIndex,sigArea.length);
+        startIndex+=sigArea.length;
+        System.arraycopy(reayonlyArea,0,cpacketBytes,startIndex,reayonlyArea.length);
+        startIndex+=reayonlyArea.length;
+        System.arraycopy(varDataArea,0,cpacketBytes,startIndex,varDataArea.length);
+        return cpacketBytes;
+    }
+
+    public static byte[] genSigArea(byte[] sigParamsArea,byte[] sigValueArea){
+        VlInt siglen=new VlInt(sigParamsArea.length+sigValueArea.length);
+        int allLen=1+siglen.size()+sigParamsArea.length+sigValueArea.length;
+        byte[] sigArea=new byte[allLen];
+        sigArea[0]=(byte) 51;
+        System.arraycopy(siglen.getVlIntBytes(),0,sigArea,1,siglen.size());
+        System.arraycopy(sigParamsArea,0,sigArea,1+siglen.size(),sigParamsArea.length);
+        System.arraycopy(sigValueArea,0,sigArea,1+siglen.size()+sigParamsArea.length,sigValueArea.length);
+        return sigArea;
+    }
+
+    public static byte[] genSigValueArea(byte[] sigValue){
+        VlInt vlInt=new VlInt(sigValue.length);
+        int allLen=sigValue.length+vlInt.size()+1;
+        byte[] sigValueArea=new byte[allLen];
+        sigValueArea[0]=(byte) 200;
+        System.arraycopy(vlInt.getVlIntBytes(),0,sigValueArea,1,vlInt.size());
+        System.arraycopy(sigValue,0,sigValueArea,1+vlInt.size(),sigValue.length);
+        return sigValueArea;
+    }
+
+    public static byte[] mergeIdentityAndReayonly(byte[] identifierArea,byte[] readonlyArea){
+        // 读取标识区负载长度
+        VlInt identifierLen;
+        try {
+            identifierLen= TLV.readVarNumber(identifierArea,new VlInt(1));
+        } catch (TLVException e) {
+            e.printStackTrace();
+            return null;
+        }
+        // 读取只读区负载长度
+        VlInt readLen;
+        try {
+            readLen= TLV.readVarNumber(readonlyArea,new VlInt(1));
+        } catch (TLVException e) {
+            e.printStackTrace();
+            return null;
+        }
+        // 合并区总长度
+        int allLen;
+        try {
+            allLen=identifierLen.getVlIntValue2Int()+readLen.getVlIntValue2Int();
+        } catch (VlIntException e) {
+            e.printStackTrace();
+            return null;
+        }
+        // 拷贝到合并数组
+        byte[] mergeArray=new byte[allLen];
+        try {
+            System.arraycopy(identifierArea,1+identifierLen.size(),
+                    mergeArray,0,identifierLen.getVlIntValue2Int());
+            System.arraycopy(readonlyArea,1+readLen.size(),
+                    mergeArray,identifierLen.getVlIntValue2Int(),readLen.getVlIntValue2Int());
+        } catch (VlIntException e) {
+            e.printStackTrace();
+            return null;
+        }
+        return mergeArray;
+    }
+
+    /**
+     * 计算整个标识区的长度，并返回该标识区
+     * @param targetArray 带签名的CPacket做编码得到的byte[]
+     * @return
+     */
+    public static byte[] extractIdentifierArea(byte[] targetArray){
+        int identifierEndPos=testPrivate.findThePos(targetArray)+10;
+        // 读取整个CPacket的总长度
+        VlInt allLen;
+        try {
+            allLen= TLV.readVarNumber(targetArray,new VlInt(1));
+        } catch (TLVException e) {
+            e.printStackTrace();
+            return null;
+        }
+        System.out.println("CPacket-负载长度: "+allLen);
+        // 计算标识区的长度
+        int identifierLen=identifierEndPos-1-allLen.size();
+        // 提取标识区
+        byte[] identifierArea=new byte[identifierLen];
+        System.arraycopy(targetArray,1+allLen.size(),identifierArea,0,identifierLen);
+        return identifierArea;
+    }
+
+    /**
+     * 提取签名参数区
+     * @param targetArray
+     * @return
+     */
+    public static byte[] extractSigParamsArea(byte[] targetArray){
+        int identifierEndPos=testPrivate.findThePos(targetArray)+10;
+        // 读取整个签名区的总长度
+        VlInt sigAreaLen;
+        try {
+            sigAreaLen = TLV.readVarNumber(targetArray,new VlInt(identifierEndPos+1));
+        } catch (TLVException e) {
+            e.printStackTrace();
+            return null;
+        }
+        System.out.println("签名区-负载长度: "+sigAreaLen);
+        // 计算签名参数区的长度
+        VlInt sigParamsAreaLen;
+        try {
+            sigParamsAreaLen=TLV.readVarNumber(targetArray,new VlInt(identifierEndPos+1
+                    +sigAreaLen.size()+1));
+        } catch (TLVException e) {
+            e.printStackTrace();
+            return null;
+        }
+        System.out.println("签名参数区-负载长度: "+sigParamsAreaLen);
+        // 提取签名参数区
+        int sigParamsAllLen;
+        byte[] sigParamsArea;
+        try {
+            sigParamsAllLen=sigParamsAreaLen.getVlIntValue2Int()+1+sigParamsAreaLen.size();
+            sigParamsArea = new byte[sigParamsAllLen];
+        } catch (VlIntException e) {
+            e.printStackTrace();
+            return null;
+        }
+        System.out.println("签名参数区-总长度："+sigParamsAllLen);
+        System.arraycopy(targetArray,identifierEndPos+1+sigAreaLen.size(),
+                sigParamsArea,0,sigParamsAllLen);
+        return sigParamsArea;
+    }
+
+    /**
+     * 产生一个新的标识区：替换最后10个字节为随机的byte[]
+     * @return
+     */
+    public static byte[] getNewIdentifierArea(byte[] oldIdentifierArray){
+        System.arraycopy(testPrivate.getFixLenthString(10).getBytes(StandardCharsets.UTF_8),
+                0,oldIdentifierArray,oldIdentifierArray.length-10,10);
+        return oldIdentifierArray;
+    }
+
+    public static byte[] genReayonlyArea(byte[] buf){
+        VlInt payloadLen=new VlInt(buf.length);
+        VlInt readonlyLen=new VlInt(buf.length+payloadLen.size()+1);
+        int allLen=buf.length+payloadLen.size()+1+readonlyLen.size()+1;
+        byte[] readonlyArea=new byte[allLen];
+        readonlyArea[0]=(byte)52;
+        System.arraycopy(readonlyLen.getVlIntBytes(),0,readonlyArea,1,readonlyLen.size());
+        readonlyArea[1+readonlyLen.size()]=(byte)204;
+        System.arraycopy(payloadLen.getVlIntBytes(),0,readonlyArea,
+                1+readonlyLen.size()+1,payloadLen.size());
+        System.arraycopy(buf,0,readonlyArea,
+                1+readonlyLen.size()+1+payloadLen.size(),buf.length);
+        return readonlyArea;
+    }
+}