Network Defense Essentials (NDE) Practice Exam 2026 - Free Network Defense Practice Questions and Study Guide

The application layer protocol that enhances the security of emails through cryptographic privacy is PGP (Pretty Good Privacy). PGP is specifically designed to provide email encryption, which protects the contents of email messages from unauthorized access. It uses a combination of symmetric and asymmetric cryptography to ensure confidentiality and integrity of the email data. By encrypting the email, PGP makes it difficult for anyone who intercepts the message to read its content, thus providing privacy to the sender and the recipient.

Other protocols listed, such as FTP (File Transfer Protocol), HTTP (HyperText Transfer Protocol), and SMTP (Simple Mail Transfer Protocol), do not focus on enhancing email security through cryptographic methods. While SMTP is used to send emails, it does not inherently provide any encryption or security measures. Similarly, FTP and HTTP are protocols for transferring files and web content, respectively, without specific mechanisms for ensuring privacy or cryptographic protection of the transmitted data. Therefore, the unique focus of PGP on email security through its cryptographic capabilities makes it the correct answer.