This is a cryptology question from the book Introduction to Modern Cryptography by Katz and Lindell. If needed, please refer to the textbook's online pdf to answer the question. Please answer BOTH parts of the question fully, and with any necessary examples/proofs. Please show ALL steps and explain logic fully. Before HMAC was invented, it was quite common to define a MAC by Mac_k(m) = H*(k||m) where H is a collision-resistant hash function. Show that this is not a secure MAC when H is constructed via the Merkle-Damgard transform. As usual, assume that the hash key a is publicly known. Generalize the Merkle-Damgard construction for any compression function that compresses by at least one bit. You should refer to a general input length l' and general output length l (with l' > l)