RSA with Cryptix: can encrypt but not decrypt? Please help.. :)

Question

Hi all,
I've been trying to do RSA encryption/decryption using a pair of keys created with keytool. I've been able to encrypt some bytes, but when I attempt to decrypt the results immediately using the private key, I received the following exception:
IllegalBlockSizeException: RSA: Cipher in DECRYPT state with an incomplete final block
Please can anyone save me out of my misery and shed some light on this problem? Thanks a great deal in advance.
Best Regards,
Kenshin
Here are the code snippets:
// 1. imported APIs:
import javax.net.ssl.*;
import java.io.*;
import java.security.*;
import java.security.interfaces.*;
import java.security.spec.*;
import java.security.cert.*;
import java.security.cert.Certificate;
import javax.crypto.*;
import javax.crypto.spec.*;
import cryptix.provider.Cryptix;
import xjava.security.Cipher;
import xjava.security.CipherInputStream;
import xjava.security.CipherOutputStream;
import xjava.security.interfaces.*;
import cryptix.provider.rsa.*;
// 2. Getting the Public Key from the created cert:
File certFile = new File("c:/keystore/jbossSSL.cer");
FileInputStream certFileInStream = new FileInputStream(certFile);
CertificateFactory cf = CertificateFactory.getInstance("X509");
Certificate cert = (Certificate)cf.generateCertificate(certFileInStream);
RSAPublicKey serverPublicKey = (RSAPublicKey)cert.getPublicKey();
// 3. Doing the encryption:
Security.addProvider( new cryptix.provider.Cryptix());
Cipher cipherInstance = Cipher.getInstance("RSA/ECB/PKCS7", "Cryptix");
CryptixRSAPublicKey vCryptixRSAPubKey = (CryptixRSAPublicKey) new RawRSAPublicKey(serverPublicKey.getPublicExponent());
cipherInstance.initEncrypt(vCryptixRSAPubKey);
System.out.println("String to be encypted: " + sRandomString);
// Sample of what is printed: String to be encypted: 2201162506010696613
ByteArrayInputStream clearTextInStream = new ByteArrayInputStream(sRandomString.getBytes());
CipherInputStream cInStream = new CipherInputStream(clearTextInStream, cipherInstance);
ByteArrayOutputStream cipherTextOutStream = new ByteArrayOutputStream();
CipherOutputStream cOutStream = new CipherOutputStream(cipherTextOutStream, cipherInstance);
byte[] buffer = new byte[8192];
int length;
while((length= cInStream.read(buffer))!=-1)
cOutStream.write(buffer, 0, length);
cOutStream.close();
cInStream.close();
cipherTextOutStream.close();
clearTextInStream.close();
String sEncodedString = new String(cipherTextOutStream.toByteArray());
System.out.println("String encrpted: " + sEncodedString);
// Sample of what is printed: String to encrpted: 2 2 01 1 6 25 0 6 01 0 6 96 6 1 3☺ ☻☻
// 4. Getting the Private key from the keystore
FileInputStream in = new FileInputStream("C:/keystore/jbossSSL.keystore");
KeyStore catalinaKeyStore = KeyStore.getInstance("jks");
catalinaKeyStore.load(in, "jbossSSL".toCharArray());
RSAPrivateKey privateK = (RSAPrivateKey)catalinaKeyStore.getKey("jbossSSL", "jbossSSL".toCharArray());
CryptixRSAPrivateKey vCryptixRSAPriKey = (CryptixRSAPrivateKey) new RawRSAPrivateKey(privateK.getPrivateExponent(), privateK.getModulus());
cipherInstance.initDecrypt(vCryptixRSAPriKey);
// 5. Doing the decryption:
ByteArrayInputStream cipherTextInStream = new ByteArrayInputStream(sEncodedString.getBytes());
cInStream = new CipherInputStream(cipherTextInStream,cipherInstance);
ByteArrayOutputStream clearTextOutStream = new ByteArrayOutputStream();
cOutStream = new CipherOutputStream(clearTextOutStream,cipherInstance);
while((length= cInStream.read(buffer))!=-1)
cOutStream.write(buffer, 0, length); >> exception thrown here
cOutStream.close();
cInStream.close();
clearTextOutStream.close();
cipherTextInStream.close();
String sDecodedString = new String(clearTextOutStream.toByteArray());
System.out.println("Stringdecrpted: " + sDecodedString);

Answer 1

Here is working RSA example Maybe will help you. (may has a few typing errors becosu I rmoved some confidential data ;) )
import java.util.*;
import javax.swing.*;
import java.io.*;
import java.security.*;
import javax.crypto.Cipher;
import xjava.security.*;
import cryptix.provider.Cryptix;
import xjava.security.interfaces.CryptixRSAPublicKey;
import xjava.security.interfaces.CryptixRSAPrivateKey;
import xjava.security.KeyGenerator;
import xjava.security.SecretKey;
public class testcipher extends javax.swing.JFrame{
    /** Creates new test */
    public testcipher() throws Exception {
    * @param args the command line arguments
    public static void main(String [] args) throws Exception  {
        Provider pd = new cryptix.provider.Cryptix();
        Security.addProvider(pd);
        KeyPairGenerator kpg = KeyPairGenerator.getInstance("RSA", "Cryptix");
        kpg.initialize(1024, new java.security.SecureRandom());
        System.out.println("Generating key pair...");
        KeyPair kp = kpg.genKeyPair();
        System.out.println("Key pair generated...");
        xjava.security.Cipher cp = xjava.security.Cipher.getInstance("RSA/ECB/PKCS7", "Cryptix");
        cp.initEncrypt(kp.getPublic());
        FileInputStream fis = new FileInputStream("c:\\temp\\b2b\\index.htm");
        CipherInputStream cin = new CipherInputStream(fis, cp);
        FileOutputStream fout = new FileOutputStream("C:\\temp\\b2b\\enc.htm");
        CipherOutputStream cout = new CipherOutputStream(fout, cp);
        byte[] buffer = new byte[8192];
        int length;
        while((length=cin.read(buffer))!=-1)
            cout.write(buffer, 0, length);
        cout.close();
        cin.close();
        fout.close();
        fis.close();
        cp.initDecrypt(kp.getPrivate());
        fis = new FileInputStream("c:\\temp\\b2b\\enc.htm");
         cin = new CipherInputStream(fis, cp);
         fout = new FileOutputStream("C:\\temp\\b2b\\dec.htm");
         cout = new CipherOutputStream(fout, cp);
                while((length=cin.read(buffer))!=-1)
            cout.write(buffer, 0, length);
        cout.close();
        cin.close();
        fout.close();
        fis.close();
}