Which of the following DoD Model layer provides non-repudiation services?

Non-repudiation is the security service that provides proof of the integrity and origin of data, preventing a sender from denying they sent the message. This is typically achieved using digital signatures, which rely on asymmetric cryptography. Digital signatures are implemented within application-level protocols that handle the data content itself, such as Secure/Multipurpose Internet Mail Extensions (S/MIME) or Pretty Good Privacy (PGP) for emails. Since these protocols and services operate where user data is generated and processed, they reside in the application layer of the DoD (TCP/IP) model.

A. network layer: The network layer, using protocols like IPsec, provides host-to-host authentication and integrity but does not offer true non-repudiation for user-specific actions or messages.

C. transport layer: The transport layer (e.g., TCP, UDP) is responsible for end-to-end data transfer reliability and flow control, not for cryptographic services like digital signatures that prove user origin.

D. data link layer: The data link layer manages local network access and physical addressing (MAC addresses); it does not have the scope or capability to provide user-level non-repudiation services.

1. Kurose

J. F.

& Ross

K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson. In Chapter 8

"Security in Computer Networks

" Section 8.3 discusses secure e-mail

detailing how protocols like PGP provide security services including non-repudiation. PGP is explicitly identified as an application-layer protocol.

2. Stallings

W. (2017). Cryptography and Network Security: Principles and Practice (7th ed.). Pearson. Chapter 20

"Electronic Mail Security

" describes S/MIME and PGP

stating

"S/MIME provides the following functions: ... sender authentication

message integrity

and non-repudiation of origin (using digital signatures)" (p. 638). These are presented as application-specific security services.

3. Forouzan

B. A. (2013). Data Communications and Networking (5th ed.). McGraw-Hill. In Chapter 32

"Security in the Internet: IPSec

SSL/TLS

PGP

VPN

and Firewalls

" Section 32.3 on PGP explains that it provides non-repudiation through digital signatures and is an application-layer protocol for securing email.