global class EncodingUtil { global EncodingUtil() { } global static Blob base64Decode(String s) { } global static String base64Encode(Blob s) { } global Object clone() { } global static Blob convertFromHex(String input) { } global static String convertToHex(Blob s) { } global static String urlDecode(String s, String enc) { } global static String urlEncode(String s, String enc) { } }