IPsec protocol that provides authentication for the origin of transmitted data as well as integrity and protection against replay attacks is the?

IPsec protocol that provides authentication for the origin of transmitted data as well as integrity and protection against replay attacks is the?

• A. Authentication Header (AH)
• B. Encapsulation Security Payload (ESP)
• C. Transport Layer Security (TLS)
• D. VPN

Answer: (A)

The key concept here is IPsec’s Authentication Header design. The protocol that provides authentication of the data’s origin, along with data integrity and protection against replay attacks, without encrypting the payload, is the one intended for verifying who sent the packet and that it hasn’t been tampered with or replayed. This is exactly what Authentication Header does: it authenticates the source and the contents, protects against replays, but does not provide confidentiality. In contrast, Encapsulation Security Payload mainly adds encryption (confidentiality) and can offer integrity/authentication as an option, but its primary feature is encryption. TLS operates at a higher layer to secure a channel, and a VPN is a general term for a secure network tunnel, not a specific IPsec protocol.

The key concept here is IPsec’s Authentication Header design. The protocol that provides authentication of the data’s origin, along with data integrity and protection against replay attacks, without encrypting the payload, is the one intended for verifying who sent the packet and that it hasn’t been tampered with or replayed. This is exactly what Authentication Header does: it authenticates the source and the contents, protects against replays, but does not provide confidentiality.

In contrast, Encapsulation Security Payload mainly adds encryption (confidentiality) and can offer integrity/authentication as an option, but its primary feature is encryption. TLS operates at a higher layer to secure a channel, and a VPN is a general term for a secure network tunnel, not a specific IPsec protocol.