Need help with generating keys from xml

Question

Hello,
I am just learning about JCE and am haveing some problems with implementing a basic program.
I have the following information:
<RSAKeyValue>
<Modulus>Base64EncodedString</Modulus>
<Exponent>Base64EncodedString</Exponent>
<P>Base64EncodedString</P>
<Q>Base64EncodedString</Q>
<DP>Base64EncodedString</DP>
<DQ>Base64EncodedString</DQ>
<InverseQ>Base64EncodedString</InverseQ>
<D>Base64EncodedString</D>
</RSAKeyValue>
From which I need to construct a public and private key. I am using RSA algorithm for the encrypting and decrypting. I am using the org.bouncycastle.jce.provider.BouncyCastleProvider provider. Any help would be greatly appreciated.
My questions are:
1) Is it possible to create the public and private key from this data?
2) How can I construct a public and private key from this data.
Thank you in advance.
Sunit.

Answer 1

Thanks for your help...I am still having problems.
I am now creating the public and private keys. I am generating the public exp, modulus, private exp, and the encrypted text from another source.
so my questions are:
1) How do I verfiy that the private and public keys that I generate are valid?
2) How do I get the decrypted text back in a readable form?
3) the decrypted text should read "ADAM"
Here is a test I wrote:
_________________STARTCODE_____________________
import java.security.*;
import java.security.spec.*;
import javax.crypto.*;
import javax.crypto.spec.*;
import java.math.BigInteger;
import org.bouncycastle.jce.provider.BouncyCastleProvider;
public class CryptTester
     protected Cipher encryptCipher = null;
     protected Cipher decryptCipher = null;
     private KeyFactory keyFactory = null;
     protected PublicKey publicKey = null;
     protected PrivateKey privateKey = null;
     private RSAPublicKeySpec publicKeySpec = null;
     private RSAPrivateKeySpec privateKeySpec = null;
     public CryptTester()
          /* Create Cipher for asymmetric encryption (
          * e.g., RSA),
          try
               encryptCipher = Cipher.getInstance("RSA", "BC");
               System.out.println("Successfully got encrypt Cipher" );
               decryptCipher = Cipher.getInstance("RSA", "BC");
               System.out.println("Successfully got decrypt Cipher" );
               keyFactory = KeyFactory.getInstance("RSA" , "BC");
               System.out.println("Successfully got keyFactory" );
          }catch ( NoSuchAlgorithmException nsae)
               System.out.println("Exception1: " + nsae.toString() );
          catch ( NoSuchPaddingException nspe)
               System.out.println("Exception2: " + nspe.toString() );
          catch ( java.security.NoSuchProviderException nspe)
               System.out.println("Exceptiont6: " + nspe.toString() );
          /* Get the private and public keys specs
          BigInteger publicMod = new BigInteger ("86e0ff4b9e95bc6dcbfd6673b33971d4f728218496adcad92021923a9be815ddb7ecf17c06f437634c62fa999a293da90d964172a21d8ce74bd33938994fbd93377f7d83ce93d523782639c75221a3c91b53927a081b2b089a61770c6d112d78d5da8a6abc452d39a276787892080d6cf17dd09537c1ec5551d89567345068ef", 16);
          BigInteger publicExp = new BigInteger ("5");
          BigInteger privateExp = new BigInteger ("50ed65fa2bf3710ead980a456b88dde62de4e0e9", 16);
          publicKeySpec = new java.security.spec.RSAPublicKeySpec( publicMod, publicExp );
          privateKeySpec = new java.security.spec.RSAPrivateKeySpec( publicMod, privateExp);
          try
               privateKey = keyFactory.generatePrivate(privateKeySpec);
               publicKey = keyFactory.generatePublic(publicKeySpec);
          }catch ( InvalidKeySpecException ivse)
               System.out.println("Exception3: " + ivse.toString() );
          try
          * initialize it for encryption with
          * recipient's public key
               encryptCipher.init(Cipher.ENCRYPT_MODE, publicKey );
               decryptCipher.init(Cipher.DECRYPT_MODE, privateKey );
     }catch ( InvalidKeyException ivse)
               System.out.println("Exception4: " + ivse.toString() );
     public String getPublicKey()
          //return new String(publicKey.getEncoded());
          return publicKey.toString();
     public String getPrivateKey()
     //          return new String(privateKey.getEncoded());
          return privateKey.toString();
     public String encryptIt(String toencrypt)
          * Encrypt the message
          try
               byte [] result = null;
               try
                    result = encryptCipher.doFinal(toencrypt.getBytes());
               catch ( IllegalStateException ise )
                    System.out.println("Exception5: " + ise.toString() );
               return new String(result);
          }catch (Exception e)
               e.printStackTrace();
          return "did not work";
     public String decryptIt(String todecrypt)
                    * decrypt the message
          try
               byte [] result = null;
               try
                    result = decryptCipher.doFinal(todecrypt.getBytes());
               catch ( IllegalStateException ise )
                    System.out.println("Exception6: " + ise.toString() );
               return new String(result);
          }catch (Exception e )
               e.printStackTrace() ;
          return "did not work";
     public static void main(String[] args)
          try
          Security.addProvider(new BouncyCastleProvider());
          CryptTester tester = new CryptTester();
          String encrypted = "307203c3f5827266f5e11af2958271c4";
          System.out.println("Decoding string " + encrypted + "returns : " + tester.decryptIt(encoded) );
          } catch (Exception e)
               e.printStackTrace();
_________________ENDPROGRAM_____________________