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Java Decryption Returns Blank

I'm currently working on an encryption program, and I'm having an issue when decrypting. The resulting file is blank, and I have been trying to find the reason for this for about an hour. My decryption code is below...
Can someone please tell me why my data might come out blank?
file = x;
FileInputStream fis = new FileInputStream(file.getAbsolutePath());
file = new File(file.getAbsolutePath().substring(0,
file.getAbsolutePath().length() - 4));
FileOutputStream fos = new FileOutputStream(file);
byte k[] = Hash.MD5(password).getBytes("UTF-8");
SecretKeySpec key = new SecretKeySpec(k, "AES");
Cipher cipher = Cipher.getInstance(algorithm);
byte[] iv = batchIV;
IvParameterSpec ivSpec = new IvParameterSpec(iv);
cipher.init(Cipher.DECRYPT_MODE, key, ivSpec);
CipherInputStream cin = new CipherInputStream(fis,
cipher);
byte[] buffer = new byte[1024];
int read = 0;
while ((read = cin.read(buffer)) != -1) {
fos.write(buffer, 0, read);
}
fos.flush();
fos.close();
cin.close();
Links go to larger code portions.
Decrypt Method Here: http://pastebin.com/2p2juUTa
Full Class Here: http://pastebin.com/hgZHT4wg
I've found that the CipherInputStream is returning -1 when you try to read from it... I'm still unsure as to what might cause this, if anyone can help.

You don't state what Hash.MD5() and Hash.MD5R() do, let alone supply the source code, but evidently MD5() returns a String, which is already an error (see below), and that MD5R() only returns the input argument, which is basically pointless. Unless you think you've discovered a way to reverse MD5? You haven't.
If you make the following changes to your code:
change MD5() to return the byte[] resulting from the MessageDigest.digest() operation that it must perform, instead of wrapping that in a String, and make the corresponding adjustments at the callings sites (i.e. remove .toByteArray("UTF-8") in a couple of places, and
change MD5R() to return the input argument, or just remove the method,
you will find that your code works.
NB:
Repeat after me: 'String is not a container for binary data'.
flush() before close() is redundant.
The File variable file should be method-local, not static.
You don't need all those File.getAbsolutePath() method calls. getPath() will work just as well in most cases, or just the File object itself in others.

Decrypting image using java

I take this code from YouTube video.From this code I encrypt image correctly but could not decrypt that image..
Can anyone help me???
Encrypt code
FileInputStream file = new FileInputStream("src/image/A.jpg");
FileOutputStream output = new FileOutputStream("src/image/AA.jpg");
byte j[]="12345678".getBytes();
SecretKeySpec kye = new SecretKeySpec(j,"DES");
System.out.println(kye);
Cipher enc = Cipher.getInstance("DES");
enc.init(Cipher.ENCRYPT_MODE,kye);
CipherOutputStream cos = new CipherOutputStream(output, enc);
byte[] buf = new byte[1024];
int read;
while((read=file.read(buf))!=-1){
cos.write(buf,0,read);
}
file.close();
output.flush();
cos.close();
Decrypt code
FileInputStream file = new FileInputStream("src/image/AA.jpg");
FileOutputStream output = new FileOutputStream("src/image/AAA.jpg");
byte j[]="12345678".getBytes();
SecretKeySpec kye = new SecretKeySpec(j,"DES");
System.out.println(kye);
Cipher enc = Cipher.getInstance("DES");
enc.init(Cipher.DECRYPT_MODE,kye);
CipherOutputStream cos = new CipherOutputStream(output, enc);
byte[] buf = new byte[1024];
int read;
while((read=file.read(buf))!=-1){
cos.write(buf,0,read);
}
file.close();
output.flush();
cos.close();
thank you

It is a relativly old post but I think I can help.
First, you should encode the Image into a ASCII representation. I would recommend Base64. It is much easier and less error attached when encrypting Base64. (Maybe not as strong but that depends on your needs)
The benefit of Base64 is the Alphabet it is using. No weird symbols at all.
1) Convert the image into a ByteArrayOutputStream by writing it with the ImageIO Class into one.
2) Encode the byte array into a Base64 String
3) Encrypt like you did above (Do not forget the flush).
4) Save bytes to new File. Delete old one.
Decrypt accordingly .....
Be aware, encoding into Base64 will blow up your memory and the file will be much bigger because of the Base64 AND the Encryption overhead.
Hope that helps !

Decrypt file in parts

So I have these large files (6GB+) that I need to decrypt on a 32 bit computer. The general procedure that I used previously was to read the entire file in memory, then pass it on to the decrypt function and then write it all back to a file. This doesn't really work due to memory limitations. I did try passing the file in parts to the decrypt function but it seems to mess up around the boundaries of where I break up the file before sending it to the decrypt function.
I've tried breaking up the file in parts relative to key size but that doesnt seem to matter. I tried a byte array of size 2048 as well as a byte aray of size 294 thinking that might be the special boundary but, no luck. I can see parts of the file correctly decrypted but parts which are total gibberish.
Is it just NOT POSSIBLE to decrypt the file in chunks? If there is a way, then how?
Here is my decryption function / my attempt to decrypt in parts.
private Path outFile;
private void decryptFile(FileInputStream fis, byte[] initVector, byte[] aesKey, long used) {
//Assume used = 0 for this function.
byte[] chunks = new byte[2048]; //If this number is greater than or equal to the size of the file then we are good.
try {
if (outFile.toFile().exists())
outFile.toFile().delete();
outFile.toFile().createNewFile();
FileOutputStream fos = new FileOutputStream(outFile.toFile());
OutputStreamWriter out = new OutputStreamWriter(fos);
IvParameterSpec spec = new IvParameterSpec(Arrays.copyOfRange(initVector, 0, 16));
SecretKeySpec key = new SecretKeySpec(aesKey, "AES");
Cipher cipher = Cipher.getInstance("AES/CFB/NoPadding");
cipher.init(Cipher.DECRYPT_MODE, key, spec);
int x;
while ((x = fis.read(chunks, 0, chunks.length)) != -1) {
byte[] dec = cipher.doFinal(Arrays.copyOfRange(chunks, 0, x));
out.append(new String(dec));
}
out.close();
fos.close();
} catch (Exception e) {
e.printStackTrace();
LOG.error(ExceptionUtils.getStackTrace(e));
}
}

Consider using Cipher#update(byte[], int, int, byte[], int) instead of doFinal() for multipart operations. This will take care of part boundaries for you.
The last part of the deciphered data can be obtained by calling the doFinal(byte[] output, int outputOffset) method.

Decrypt the encrypted file content?

I am having a problem decrypting a file using RSA public key decryption. My process is to receive the xml file, encrypt the content, and write it back to the same file. Another function decrypts the content. My source code is:
public void decryptFile(String fileName,PrivateKey privateKey) throws Exception {
Cipher cipher = Cipher.getInstance("RSA/ECB/PKCS1Padding");
cipher.init(Cipher.DECRYPT_MODE, privateKey);
FileInputStream fis = new FileInputStream(fileName);
File file=new File("decryptedfile.xml");
if(file.exists()) {
file.delete();
}
FileOutputStream fos = new FileOutputStream("decryptedfile.xml");
CipherInputStream cis = new CipherInputStream(fis, cipher);
int i;
byte[] block = new byte[32];
//System.out.println("Read : "+cis.read(block));
while ((i = cis.read(block)) != -1) {
System.out.println(String.valueOf(i));
fos.write(block, 0, i);
}
fos.close();
}
I just pass in the name of the encrypted file, and the corresponding private key value, into the function. However the cis.read(block) returns -1 on the first attempt. Can anyone suggest how I can decrypt the encrypted file?

Your file is almost certainly not RSA encrypted. Its probably encrypted with AES under a random symmetric key and the key is then encrypted with RSA.
You are assuming someone actually encrypted the entire file using just RSA. Assuming the implementation even lets you do this (i've seen ones that throw exceptions when one tries this), it would be way way way too slow to do anything useful.

Java: How to write binary files?

I have been doing web programming for several years now and since then I have not done any programming for desktop applications, and I have forgotten so many things. Please be patient if this is too simple.
Now I have this situation:
I am trying to store some hashed words in a file. I think I should use binary files for this (please correct me if I am wrong). But I have no idea how should I write the words to the file. I tried many ways, but when I read back the file, and try to decrypt the words, I get BadPaddingException.
Does anyone have any idea how to write the words to a file?
P.S: I use this code for encrypting/decrypting the words (I got it from another StackOverflow thread, with a few modifications):
public static byte[] encrypt(String property) throws GeneralSecurityException, UnsupportedEncodingException {
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey key = keyFactory.generateSecret(new PBEKeySpec(password));
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.ENCRYPT_MODE, key, new PBEParameterSpec(salt, 20));
return pbeCipher.doFinal(property.getBytes("UTF-8"));
}
public static String decrypt(byte[] property) throws GeneralSecurityException, IOException {
SecretKeyFactory keyFactory = SecretKeyFactory.getInstance("PBEWithMD5AndDES");
SecretKey key = keyFactory.generateSecret(new PBEKeySpec(password));
Cipher pbeCipher = Cipher.getInstance("PBEWithMD5AndDES");
pbeCipher.init(Cipher.DECRYPT_MODE, key, new PBEParameterSpec(salt, 20));
return new String(pbeCipher.doFinal(property));
}

Well, just use FileInputStream and FileOutputStream =)
Sample writing:
// encrypted data in array
byte[] data = ...
FileOutputStream fos = ...
fos.write(data, 0, data.length);
fos.flush();
fos.close();
Sample reading:
File inputFile = new File(filePath);
byte[] data = new byte[inputFile.length()];
FileInputStream fis = new FileInputStream(inputFile);
fis.read(data, 0, data.length);
fis.close();
Above code assumes that one file holds single encrypted item. If you need to hold more than one item in the single file, you'll need to devise some format scheme for that. For example, you can store number of bytes in encrypted data as 2 bytes, before data itself. 2 bytes per item means encrypted item can not be longer than 2^16 bytes. Of course, you can use 4 bytes for length.

Saving as a text document would seem to make more sense to me, the data is already a so there's no need to convert it to a byte[] and if you need to read from the file would be pretty convenient. Unless you're saving it from the web and its already coming through a socket as a byte[]. I know it says don't provide your opinion but its strictly a matter of opinion, that was the only part of your question left unanswered by the previous two answered