Producing The Same SHA-512 Hash In Java And PHP

I needed to calculate the same SHA-512 hashes in Java and PHP. I thought that this would be a quite easy exercise. Unfortunately, it was not, so I decided to publish the code that finally produces the same hashes. First, let us have a look at the PHP code, which is really easy:

$toHash = 'someRandomString';
$hash = hash('sha512', $to_hash);

Easy, isn’t it? 🙂 In Java, it is a bit more complicated:

public String generateHash() {
    String toHash = "someRandomString";
    MessageDigest md = null;
    byte[] hash = null;
    try {
        md = MessageDigest.getInstance("SHA-512");
        hash = md.digest(toHash.getBytes("UTF-8"));
    } catch (NoSuchAlgorithmException e) {
        e.printStackTrace();
    } catch (UnsupportedEncodingException e) {
        e.printStackTrace();
    }
    return convertToHex(hash);
}

/**
* Converts the given byte[] to a hex string.
* @param raw the byte[] to convert
* @return the string the given byte[] represents
*/
private String convertToHex(byte[] raw) {
    StringBuffer sb = new StringBuffer();
    for (int i = 0; i < raw.length; i++) {
        sb.append(Integer.toString((raw[i] & 0xff) + 0x100, 16).substring(1));
    }
    return sb.toString();
}

This will result in exactly the same SHA-512 hash in Java and in PHP.

If that helps someone, I am happy to read your comment 🙂