private String SHA1 (String text) {
    	try {
		    MessageDigest md = MessageDigest.getInstance("SHA-1");
		    byte[] sha1hash = new byte[40];
		    md.update(text.getBytes("iso-8859-1"), 0, text.length());
		    sha1hash = md.digest();
		    return convToHex(sha1hash);
    	} catch (Exception e) {
    		e.printStackTrace();
    		return null;
    	}
    }