Private Key for RSAalgorithm

Question

Hello,
I used RSA algorithm for encryption and i can send the encrypted text to the server , on the server side
in order to decrypt the message i passed the public key, but how to generate the private key on the server side, i am a beginner in cryptography, can anybody help me , if possible give me the coding for encryption and decryption which will work on the client side for encryption and server side for decryption,i need RSA algorithm for it

Answer 1

well, but i just used receivers public key to encrypt the data at the senders side, at the receivers side both secret and public key is generated, and the receivers secret key is used to decrypt. The ecrypted text can be accessed at the receivers side but it can't be decrypted, my program part is given below
Sender's side
// Create a new instance of Message class, to encrypt / decrypt message
Message M = new Message();
// Create a new instance of Keys, to generate keys
Keys K = new Keys ();
// Set the Plain Text message
M.PlainText = ta.getText(); (ta is the text area i displayed the text file)
// Display the Plain Text message
System.out.println (" Message:" + M.PlainText);
// Set the Number of Rounds
M.NumRounds = 2;
// Display the Number of Rounds
System.out.println (" Rounds:" + M.NumRounds);
// Create RSA Public, Secret key pairs
K.CreateKeys();
// Display Public Key individual number
System.out.println ("Public Key:" + K.PublicKey);
// Display Secret Key individual number
System.out.println ("Secret Key:" + K.SecretKey);
// Display n, the shared number (of Public and Secret Keys)
System.out.println (" n:" + K.n);
// Encrypt the Message
M.Encrypt (publicKey, n);
/* where publickey and n are generated at the receivers side and saved in the database, which is taken
at the senders side to encrypt the data. */
// Display the Encrypted Message
System.out.println (" Encrypted Message:" + M.CipherText);
String crp=M.CipherText.toString();
AT the receiving side
// Create a new instance of Message class, to encrypt / decrypt message
Message M = new Message();
// Create a new instance of Keys, to generate keys
Keys K = new Keys ();
// Set the Plain Text message
//M.PlainText = ta.getText();
// Display the Plain Text message
//System.out.println (" Message:" + M.PlainText);
// Set the Number of Rounds
M.NumRounds = 2;
// Display the Number of Rounds
System.out.println (" Rounds:" + M.NumRounds);
// Create RSA Public, Secret key pairs
K.CreateKeys();
// Display Public Key individual number
System.out.println ("Public Key:" + K.PublicKey);
pbk=K.PublicKey.toString();
// Display Secret Key individual number
System.out.println ("Secret Key:" + K.SecretKey);
// Display n, the shared number (of Public and Secret Keys)
System.out.println (" n:" + K.n);
bi=new BigInteger (bi.toString().concat(String.valueOf(K.SecretKey)));
bn=new BigInteger (bn.toString().concat(String.valueOf(K.n)));
System.out.println("SECRET:"+bi);
System.out.println("N:"+bn);
M.Decrypt(bi,bskbi); // where bi is secret generated at the recivers side and bn is retrieved
from the database , n = (p-1)*(q-1) where p and q are two large priome numbers */
at the receivers side the encrypted text can be accessed , but the text can be decrypted, what is the problem here, can u help me to change the codings
thanks in advance