Update (Sept 21, 2018): Negligible functions map to the real positive numbers.
Update Oct 17: Including missing probability analysis
Update Oct 17: Fixed a parsing issue in the reduction for Exercise 23.
Oct 17: Update on the Exercise Sheet for clarity.
Oct 17: Second update on the Exercise Sheet for a nicer Feistel construction figure and correcting a typos in the definition of quadratic-key PRF: It was using the letter f in positions where it should use letter g.
Oct 17: Third update on the Feistel description.
This exercise sheet is aimed at helping to understand security models, i.e., encoding security properties as indistinguishability between two games. In particular, the goal is to understand the UNF-CMA model introduced in the lecture and the properties that it encodes. The exercise sheet discusses strengthenings and weakenings of the definition.
Oct 31: Minor update to clarify the definition of the first MAC scheme m' by using a for loop; added a missing prime
Nov 2: Added a missing \tau in the verification algorithm
Update 6.11: Corrected typos and algorithm on exercise 31, added an adversary to exercise 32.