Inbuilt functions for RSA

Respected Sir,

I am very sorry to write ambigous post. Actually we are students who are keen to learn Cryptography using Java. We are trying to implement 3 crytographic algorithms ie Diffie-hellman to share the keys and then we are using DES to encrypt the secret message using the shared key and then we are incorporating RSA for encrypting the secret key of the DES and then send it to the user from the server. Sir, our project may look very silly to you. But we need guidance from you since we arent getting any proper guidance here. And so,we thought of using inbuilt functions for these algorithms.

We hope you that you will understand our problem and this post too.

Thanking You

KITSa at 2007-7-8 21:58:35 >

sir....

we are nw able to use our own key for encryption but on the client side

its not decrypting. its not getting the correct byte value. we don kno hw to correct it. so plz help.

thank you sir.

waitin for ur reply.

server side:

SecretKey key = new SecretKeySpec(b, "DES");

System.out.println("KEY for encryption:"+key);

byte[] initVector = new byte[] { 0x10, 0x10, 0x01, 0x04, 0x01, 0x01, 0x01, 0x02 };

AlgorithmParameterSpec algParamSpec = new IvParameterSpec(initVector);

Cipher m_encrypter = Cipher.getInstance("DES/CBC/PKCS5Padding");

Cipher m_decrypter = Cipher.getInstance("DES/CBC/PKCS5Padding");

m_encrypter.init(Cipher.ENCRYPT_MODE, key,algParamSpec);

m_decrypter.init(Cipher.DECRYPT_MODE, key,algParamSpec);

System.out.println("\n Enter data to be encrypted : ");

BufferedReader brr=new BufferedReader(new InputStreamReader(System.in));

String strr=brr.readLine();

byte[] clearText = strr.getBytes();

byte[] encryptedText = m_encrypter.doFinal(clearText);

System.out.println("Data for encryption:");

System.out.println(new String(clearText));

System.out.println("Encrypted data:");

System.out.println(new String(encryptedText));

//SENDING

PrintWriter p=new PrintWriter(s.getOutputStream(),true);

p.println(encryptedText);

client side:

//KEY GENERATION

SecretKey key = new SecretKeySpec(b, "DES");

System.out.println("KEY for decryption:"+key);

// for CBC; must be 8 bytes

byte[] initVector = new byte[] { 0x10, 0x10, 0x01, 0x04, 0x01, 0x01, 0x01, 0x02 };

AlgorithmParameterSpec algParamSpec = new IvParameterSpec(initVector);

Cipher m_decrypter = Cipher.getInstance("DES/CBC/PKCS5Padding");

m_decrypter.init(Cipher.DECRYPT_MODE, key,algParamSpec);

//RECEIVING

BufferedReader b2=new BufferedReader(new InputStreamReader(s.getInputStream()));

String key1=b2.readLine();

System.out.println("encrypted text received is:"+key1);

byte[] encryptedText = key1.getBytes("utf-8");

System.out.println("in bytes:"+encryptedText);

//System.out.println(new String(encryptedText));

System.out.println("test1");

byte[] decryptedText = m_decrypter.doFinal(encryptedText);

System.out.println("test1");

System.out.println("\n Decrypted data : ");

System.out.println(new String(decryptedText));

s.close();

KITSa at 2007-7-8 21:58:35 >