5.1 Crypto Placements in Networks5.2 Public-Key Infrastructure5.3 IPsec: A Security Protocol at the Network Layer5.4 SSL/TLS: Security Protocols at the Transport Layer5.5 PGP and S/MIME: Email Security Protocols5.6 Kerberos: An Authentication Protocol5.7 SSH: Security Protocols for Remote Logins5.8 Electronic Voting Protocols5.9 Closing Remarks5.10 Exercises