problem usding RSA encode/decode while sending data via sockets

[mahta_gh]

hi
i need to encode data by public key and send them to server via sockets and decode them using private key there
i generated pairkeys and i think i'v done every thing
but in server side , when i am trying to decode , i get -> Exception in thread "main" javax.crypto.BadPaddingException: Data must start with zero

the RSAHandler which i'm using is not written by me , i just found it in internet
here is my code

PublicKey readKeyFromFileC(String keyFileName) throws IOException {

InputStream in = new FileInputStream(keyFileName);
ObjectInputStream oin = new ObjectInputStream(new BufferedInputStream(in));
try {
BigInteger m = (BigInteger) oin.readObject();
BigInteger e = (BigInteger) oin.readObject();
RSAPublicKeySpec keySpec = new RSAPublicKeySpec(m, e);
KeyFactory fact = KeyFactory.getInstance("RSA");
PublicKey pubKey = fact.generatePublic(keySpec);
return pubKey;
} catch (Exception e) {
throw new RuntimeException("Spurious serialisation error", e);
} finally {
oin.close();
}
}

PrivateKey readKeyFromFileS(String keyFileName) throws IOException {


InputStream in = new FileInputStream(keyFileName);
ObjectInputStream oin = new ObjectInputStream(new BufferedInputStream(in));
try {
BigInteger m = (BigInteger) oin.readObject();
BigInteger e = (BigInteger) oin.readObject();
RSAPrivateKeySpec keySpec = new RSAPrivateKeySpec(m, e);
KeyFactory fact = KeyFactory.getInstance("RSA");
PrivateKey privKey = fact.generatePrivate(keySpec);
return privKey;
} catch (Exception e) {
throw new RuntimeException("Spurious serialisation error", e);
} finally {
oin.close();
}
}

public String rsaEncrypt(byte[] data) throws Exception {
PublicKey pubKey = (PublicKey) readKeyFromFileC("/public.key");
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, pubKey);
byte[] cipherData = cipher.doFinal(data);
return cipherData.toString();
}


public String rsaDecrypt(byte[] data) throws Exception {
PrivateKey privKey = (PrivateKey) readKeyFromFileS("/private.key");
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.DECRYPT_MODE, privKey);
byte[] deCipherData = cipher.doFinal(data);
return deCipherData.toString();
}


--------------
here is the client side code

public void sendToServer(String sendText) throws Exception {
Socket clientSocket = new Socket("localhost", 5000);
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter (clientSocket.getOutputStream())), true);
out.println(new String(sendText));
}

tcpClient.sendToServer(rsaHandler.rsaEncrypt(login Info.getBytes()));
String res = tcpClient.RecieveFromServer();

-------------------------------
and server side code

RSAHandler rsaHandler = new RSAHandler();
Message = rsaHandler.rsaDecrypt(fromclient.getBytes()).toCha rArray();





please help me , its long time that i'm dealing with this code
i think maybe the problem is in converting string to byte / byte to string in encoding/decoding and sending process , but i can't fix it
thanks in advance if somebody can solve my problem


the italic line , is where i get that exception javax.crypto.BadPaddingException: Data must start with zero

[DarrylBurke]

Don't double post the same question and don't hijack another poster's thread. Also, don't post to old, long dead threads.

Your post in Padding Problem as been removed.

db