How can I calculate the SHA-256 hash of a string in Android?

Question

I\'m trying to get the SHA256 of a string in Android.

Here is the PHP code that I want to match:

echo bin2hex(mhash(MHASH_SHA256,\"asdf\"));
//output         


        

Answer 1

You are along the right lines, but converting the bytes is a little more complicated. This works on my device:

// utility function
    private static String bytesToHexString(byte[] bytes) {
        // http://stackoverflow.com/questions/332079
        StringBuffer sb = new StringBuffer();
        for (int i = 0; i < bytes.length; i++) {
            String hex = Integer.toHexString(0xFF & bytes[i]);
            if (hex.length() == 1) {
                sb.append('0');
            }
            sb.append(hex);
        }
        return sb.toString();
    }

// generate a hash

    String password="asdf";
    MessageDigest digest=null;
    String hash;
    try {
        digest = MessageDigest.getInstance("SHA-256");
        digest.update(password.getBytes());

        hash = bytesToHexString(digest.digest());

        Log.i("Eamorr", "result is " + hash);
    } catch (NoSuchAlgorithmException e1) {
        // TODO Auto-generated catch block
        e1.printStackTrace();
    }

Source: bytesToHexString function is from the IOSched project.