Systems Security Certified Practitioner – SSCP – Question1024

Which of the following statements pertaining to link encryption is false?

A. It encrypts all the data along a specific communication path.
B. It provides protection against packet sniffers and eavesdroppers.
C. Information stays encrypted from one end of its journey to the other.
D. User information, header, trailers, addresses and routing data that are part of the packets are encrypted.

Correct Answer: C

Explanation:

When using link encryption, packets have to be decrypted at each hop and encrypted again.
Information staying encrypted from one end of its journey to the other is a characteristic of end-to-end encryption, not link encryption. Link Encryption vs. End-to-End Encryption
Link encryption encrypts the entire packet, including headers and trailers, and has to be decrypted at each hop.
End-to-end encryption does not encrypt the IP Protocol headers, and therefore does not need to be decrypted at each hop.
Reference: All in one, Page 735 & Glossary and Source: WALLHOFF, John, CBK#5 Cryptography (CISSP Study Guide), April 2002 (page 6).