An early standard for encrypting HTTP documents, Secure HTTP (S-HTTP) is designed to send individual messages securely. SSL is designed to establish a secure connection between two computers. SET was originated by VISA and MasterCard as an Internet credit card protocol using digital signatures. Kerberos is an authentication system.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 89.