Internet protocol security (IPSec), point-to-point tunneling protocol (PPTP), and secure sockets Layer (SSL) all use Which of the following to prevent replay attacks?

The correct answer is D. Randomly generated nonces. IPSec, PPTP, and SSL all use randomly generated nonces to prevent replay attacks. A nonce is a number that is used only once in a cryptographic communication. It is usually sent along with the encrypted message to ensure freshness and uniqueness. A replay attack is when an attack

Submitted by brentm· Mar 5, 2026Communication and Network Security

Question

Internet protocol security (IPSec), point-to-point tunneling protocol (PPTP), and secure sockets Layer (SSL) all use Which of the following to prevent replay attacks?

Options

ALarge Key encryption
BSingle integrity protection
CEmbedded sequence numbers
DRandomly generated nonces

How the community answered

(37 responses)

A
3% (1)
B
8% (3)
C
14% (5)
D
76% (28)

Explanation

IPSec, PPTP, and SSL all use randomly generated nonces to prevent replay attacks. A nonce is a number that is used only once in a cryptographic communication. It is usually sent along with the encrypted message to ensure freshness and uniqueness. A replay attack is when an attacker intercepts and retransmits a valid message to gain unauthorized access or cause a denial of service. By using nonces, the protocols can detect and reject any repeated messages that have the same nonce value.

Topics

#Replay attacks#nonces#IPSec#SSL/TLS

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