Serialization ruins my hash value...

Question

Hello all,
i am in the stage of switching from asymmetric to symmetric cryptography after the successful receival of a symmetric key..
in the client now i take a string from the user and i create a hash value using the SHA1 algorithm using the following :
public static byte[] hashIt(String str){
          MessageDigest md = null;
          byte[] result=null;
          try {
               md = MessageDigest.getInstance("SHA1");
               result = md.digest(str.getBytes("UTF-8"));     
          }catch(NoSuchAlgorithmException e) {
               System.out.println("No Such Algorithm Exception "+e);     
          }catch(UnsupportedEncodingException e) {
               System.out.println("Unsupported Encoding Exception "+e);     
          System.out.println("I HASHED IT TO : "+result);
          return result;
     }i then save the message and its hashed value into an object called myPacketMessage and i use symmetric encryption to encrypt the object to a sealedObject and then serialize it to a udp packet that is being sent. Unfortunately on the receiver i obtain a different hash value than the one stored (i am not saying that i create the hash of the message and it is different from the one stored, i am saying that the hash value that i just get from the packet is different from the one that client put in it)...
In fact, i did some testing serializing and deserializing the object on the client and again the hashed value stored is different from the one retrieved. i then tried not even encrypt the object to a sealed object but just to serialize it with the following code and again it fails...
//text is a string retrieved from the user
pcktText.setHash(sp.hashIt(text));
pcktText.setMsg(text);
System.out.println("I set hash : "+pcktText.getHash());
sentPacket = sp.serializeObject(pcktText, serverIP, serverPort);
MyPacketMessage textToBeRot13=new MyPacketMessage();
          textToBeRot13=(MyPacketMessage)sp.deserializeObject(sentPacket);
System.out.println("After the serialize/deserialize the hash is : "+textToBeRot13.getHash());
          and the values are :
I set hash : [B@c55e36
After the serialize/deserialize the hash is : [B@1621e42
the function that does the serialization is the following (and i suspect that the problem is in here, but i dont know where (because it works in other cases that i store signatures in the packet!!!)
public static DatagramPacket serializeObject(MyPacketInterface myPacket, InetAddress IP, int PORT){
          byte[] sendBuf=new byte[2048];           
          DatagramPacket tempPacket=new DatagramPacket(sendBuf,sendBuf.length, IP, PORT);
          try{
               ByteArrayOutputStream byteStream = new ByteArrayOutputStream(2048);
               ObjectOutputStream os = new ObjectOutputStream(new BufferedOutputStream(byteStream));
               os.flush();
               os.writeObject(myPacket);
               os.flush();
               os.close();
               sendBuf = byteStream.toByteArray();
               tempPacket.setData(sendBuf);
          } catch (IOException e) {
               System.out.println("IOException "+e);
          return tempPacket;
     }and the deserialize the following :
public static MyPacketInterface deserializeObject(DatagramPacket packet){
          MyPacketInterface myPacket=null;
          byte[] recvBuf = packet.getData();
          try {
               ByteArrayInputStream byteStream = new ByteArrayInputStream(recvBuf);
               ObjectInputStream is = new ObjectInputStream(new BufferedInputStream(byteStream));
               myPacket = (MyPacketInterface)is.readObject();
               is.close();
          } catch (ClassNotFoundException e){
               System.out.println("ClassNotFoundException :"+e);
          } catch(IOException e){
               System.out.println("IOException " +e);
          return myPacket;
     }any help would be greatly appreciated!!!

Answer 1

hm, could you please elaborate on that because i am not getting it...
i am not using the MD5 hash algorithm.. i am using the SHA1 to make a hash and store it on a byte[] variable .. You said that i should print out the bytes right? i think this is what i am doing in the system.out.print statements with the getHash() functions that looks like the following
public class MyPacketMessage extends MyPacket implements Serializable {
     private byte[] hash;
     private String msg;
     public MyPacketMessage(){
          super();
          this.hash=null;
          this.msg=new String();
     public byte[] getHash(){
          return this.hash;
(....)