Exercise 2 (The RSA Signature Scheme (. Consider the "textbook" RSA signature scheme as a prototype of a public-key signature scheme. 1. Describe how Bob should verify Alice's signatures on a message M. 2. Define the various security definitions for signature schemes. 3. Suppose that the hash function H used in the scheme is not preimage resistant. Describe an attack on the "textbook" RSA signature scheme. 4. Suppose now that H is not 2nd preimage resistant. Describe an attack on the "textbook" RSA signature scheme. 5. Finally, suppose that H is not collision resistant. Describe an attack on the "textbook" RSA signature scheme.

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