. Answer the following questions briefly but concisely: a. What are the services needed to securely b. What are the reasons for the current interest c What are the problems facing cross- d. List the security services provided by a exchange messages in e-commerce in elliptic curve cryptography (ECC)? certification? How are the financial institutions attempting to solve them? digital signature 2. Discuss the trustworthiness of root certificates provided by browsers. 3. When a session is resumed, which of the following cryptographic secrets need to be recalculated? a. Pre-master secret b. Master secret e. Authentication keys d. Encryption keys e. Initial Vectors (IVs) 4. Compare and contrast a conventional signature and a digital signature s. Use the Internet (or other available resources) to find information about the following compression functions, and compare them with SHA-512. a. SHA-224 b. SHA-256 c. SHA-384 6. In a public-key infrastructure (PKD: a. List the duties of a PKI. b. Show how Userl, knowing only the public key of the root Certificate Authority (CA), can obtain a verified copy of User3's public c Define the X.509 recommendation and state its purpose