Network security concepts: Compared to end-to-end encryption, how secure is link encryption in typical multi-hop networks?

Introduction / Context:
Encryption can be applied on individual links (hop-by-hop) or end-to-end between communicating endpoints. Understanding the implications of where decryption occurs clarifies the threat model and the confidentiality guarantees provided to users.

Given Data / Assumptions:

• Multi-hop path with intermediate routers/switches.
• Link encryption encrypts traffic on each physical/logical link separately.
• End-to-end encryption protects payloads from sender to receiver.

Concept / Approach:
With link encryption, data are decrypted and re-encrypted at each intermediate device. Any compromised intermediate node can access plaintext, so confidentiality depends on every hop. End-to-end encryption keeps data encrypted across the entire path; only endpoints hold keys, so intermediates cannot read content. Therefore, link encryption provides weaker confidentiality than end-to-end in most scenarios.

Step-by-Step Solution:

Verification / Alternative check:
Standards and best practices (e.g., TLS over the internet) endorse end-to-end to prevent intermediary snooping; VPNs may combine both for layered defense.

Why Other Options Are Wrong:
More secure: incorrect due to hop exposure. Cannot be used publicly: false; link encryption is common on ISP backbones. Used only to debug: false; it is a security technique, not a diagnostic tool. None: incorrect because “less secure” is accurate.

Common Pitfalls:
Assuming encryption anywhere guarantees full privacy; ignoring trusted middleboxes that terminate link encryption.

Final Answer:
is less secure than end-to-end encryption