Question

I have an object called users that I use to store user objects that have credential information.

I call this code to make a new default user.

user def = new user("admin","admin",md5hash(("osa").toCharArray()),1,-1);

This def user is added to the array.

These users are stored inside an array. When I loop through the array to check whether it is valid or not, I use this snippet of code to output information about users inside the array, namely the username and password in string format from a byte array.

System.out.println(userarray.get(x).username);
System.out.println((userarray.get(x).password).toString());

The passwords are all encrypted in md5 and stored as a byte array using this code:

byte[] md5hash(char[] passwd) {
    String passwdtext = new String(passwd);
byte[] passdigest = null;
    try {
        MessageDigest md5 = MessageDigest.getInstance("MD5");
        md5.reset();
        md5.update(passwdtext.getBytes("UTF-8"));
        passdigest = md5.digest();

    } catch (NoSuchAlgorithmException e) {

        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    return passdigest;
}

When I try entering “admin” for user and “osa” for the password, I output these as well and compare them with the values in the array

I get the following:

admin [B@2b12e7f7

and compare to the value inside the array:
admin [B@663b1f38

Why are they different?

Answer 1

The toString() byte array does not encode the data. What you are looking at is the memory address of said arrays. The “[B” means byte array. The hex after that is the address.

Instead, you should invoke Arrays.toString(digestArray); which will print the actual values in the array.

Also, it’s not clear by the code that you posted, but if you’re trying to use == to compare the two arrays, that will fail for the same reason. The == operator on arrays compares memory addresses. Here again, you should use Arrays.equals(a1, a2) to compare.