Answer each topic in at least two paragraphs. Topic 1: List and briefly discuss categories of security services. Topic 2: Brief discuss the Playfair cipher. Topic 3: Discuss how the Data Encryption Standard (DES) works. Topic 4: Discuss the strength of the Data Encryption Standard (DES). Topic 5: Briefly discuss the main difference between public key cryptography and DES Topic 6: Briefly discuss the RSA encryption algorithm. Topic 7: Briefly discuss, using your own experience, various virtual private networks and various access control approaches. Topic 8: Briefly discuss secure e-mail communications using cryptographic protocols and secure wireless communications using cryptographic protocols.