Which of the following are the ways of sending secure e-mail messages over the Internet?
Each correct answer represents a complete solution. Choose two.

A.
TLS

B.
PGP

C.
S/MIME

D.
IPSec

Explanation:

Pretty Good Privacy (PGP) and Secure Multipurpose Internet Mail Extensions (S/MIME) are two ways
of sending secure e-mail messages over the Internet. Both use public key cryptography, where users
each possess two keys, a public key for encrypting, and a private key for decrypting messages.
Because PGP has evolved from a free distribution, it is more popular than S/MIME.
Answer option A is incorrect. Transport Layer Security (TLS) is an application layer protocol that uses
a combination of public and symmetric key processing to encrypt data.
Answer option D is incorrect. Internet Protocol Security (IPSec) is a standard-based protocol that
provides the highest level of VPN security. IPSec can encrypt virtually everything above the
networking layer. It is used for VPN connections that use the L2TP protocol. It secures both data and
password.
IPSec cannot be used with Point-to-Point Tunneling Protocol (PPTP).
TechNet, Contents: “Ask Us About… Security, October 2000”