Java FileInputStream giving random output every time it runs

Question

I need to generate an IV for an AES encrypted file, and I'm doing it like so:

private void generateIv() {
    SecureRandom rnd = new SecureRandom();

    byte tempiv[] = new byte[16];
    rnd.nextBytes(tempiv); 

    System.out.println("IV Generated: " + tempiv.toString() + ", Length: " + tempiv.length);

    try{
        File outfile = new File("initvector.iv");
        FileOutputStream ivfile = new FileOutputStream(outfile);  
        DataOutputStream dos = new DataOutputStream(ivfile);
        dos.write(tempiv);
        ivfile.close();
        dos.close();
    } catch(Exception e){
        e.printStackTrace();
    }
}

Then, I display it to the console like this:

private void displayiv() {
    FileInputStream ivout = null;

    try {
        ivout = new FileInputStream("initvector.iv");
    } catch (FileNotFoundException e) {
        e.printStackTrace();
    }
    // DataInputStream dis = new DataInputStream(ivout);

     byte[] fileiv = new byte[16];

     try {
        ivout.read(fileiv);
        //dis.close();
        ivout.close();
    } catch (IOException e) {
        e.printStackTrace();
    }

     System.out.println(fileiv);
}

But the problem is that the output is different every time I call the displayiv() method... This is a sample output from the console.

IV Generated: [B@6276ae34, Length: 16
[B@42dafa95
[B@6500df86
[B@402a079c
[B@59ec2012

As you you can see the iv is generated fine, but trying to read it from the file gives a different result every time. In the displayiv() method I also tried to wrap the fileinputstream in a DataInputStream but the problem still persists. Why is this?

Java FileInputStream giving random output every time it runs

0 Answers0