few characters missing after decryption

问题:

This is my original xml:

<?xml version="1.0" encoding="UTF-8"?>
<table>
    <row>
        <id>12</id>
        <name>Mickey Mouse</name>
    </row>
</table>

This is the output after going through encryption/decryption process

<?xml version="1.0" encoding="UTF-8"?>
<table>
    <row>
        <id>12</id>
        <name>Mickey Mouse</name>
    </row>
</

As you can see, few characters are missing.

here is my code.

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;

import javax.crypto.BadPaddingException;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.IllegalBlockSizeException;
import javax.crypto.NoSuchPaddingException;
import javax.crypto.spec.SecretKeySpec;

public class Decrypter
{

    /**
     * @param args
     * @throws IOException
     * @throws NoSuchPaddingException
     * @throws NoSuchAlgorithmException
     * @throws InvalidKeyException
     * @throws BadPaddingException
     * @throws IllegalBlockSizeException
     */
    public static void main(String[] args) throws IOException,
        NoSuchAlgorithmException, NoSuchPaddingException,
        InvalidKeyException, IllegalBlockSizeException, BadPaddingException
    {
    // TODO Auto-generated method stub
    File iFile = new File("normal.xml");
    FileInputStream fis = new FileInputStream(iFile);

    File oFile = new File("normal.xml.encrypted");
    FileOutputStream fos = new FileOutputStream(oFile);

    String algorithm = "DESede";
    byte[] keyBytes = new byte[] { 0x34, 0x11, 0x12, 0x06, 0x34, 0x11,
        0x12, 0x06, 0x34, 0x11, 0x12, 0x06, 0x34, 0x11, 0x12, 0x06,
        0x34, 0x11, 0x12, 0x06, 0x34, 0x11, 0x12, 0x06 };

    SecretKeySpec key = new SecretKeySpec(keyBytes, algorithm);

    // generates encrypted output from normal.xml.
    Cipher cipher = Cipher.getInstance(algorithm);
    cipher.init(Cipher.ENCRYPT_MODE, key);
    CipherOutputStream cos = new CipherOutputStream(fos, cipher);

    int b;
    while ((b = fis.read()) != -1)
    {
        cos.write(b);
    }

    fos.close();
    fos = null;
    fis.close();
    fis = null;

    System.out.println("done");

    // decrypt encrypted xml to normal xml. 
    File ieFile = new File("normal.xml.encrypted");
    FileInputStream fies = new FileInputStream(ieFile);

    Cipher ieCipher = Cipher.getInstance(algorithm);
    ieCipher.init(Cipher.DECRYPT_MODE, key);
    CipherInputStream cis = new CipherInputStream(fies, ieCipher);

    File oeFile = new File("normal.xml.encrypted.xml");
    FileOutputStream foes = new FileOutputStream(oeFile);

    int c;
    while ((c = cis.read()) != -1)
    {
        foes.write(c);
    }

    foes.close();
    cis.close();
    fies.close();

    System.out.println("done done");
    }

}

Please help. Thanks.

回答1:

Found the problem. Do

        cos.close();

before the line:

        fos.close();

At least, that fixed it on my box.

回答2:

After writing the encrypted output, call

cos.close();

instead of

fos.close();

Closing the cos object also closes the underlying fos object.

回答3:

Try closing (or at least flushing) your CipherOutputStream (cos) as there may be some bytes that never got written to the original encrypted file.

回答4:

agree with JASON. You have to close Cipher stream instead of file. even you can explicitly close both but make sure you close cipher stream first and then file stream. only flushing will not help. at least it didn't worked for me. :)