(a) You generated a self-signed certificate for your web-server. What instructions do you need to provide to the users of your web-server so that they can validate the authenticity of your server (i.e, how can they be sure that their web browser is connecting to your server and, e.g., not to a server of an attacker)? (5 marks) (b) Consider the simple hash function that is constructed by interpreting the input byte-wise as natural number (i.e., each byte represents a natural number between 0 and 255) and computing the sum of all bytes modulo 255. Consider the four-byte sequence [5,127,127,7], its hash value is 5+127+127+7mod255=11 Briefly argue whether this hash function is 2nd-pre-image resistant