Which of the following statements pertaining to key management is incorrect?

The correct answer is B. When not using the full keyspace, the key should be extremely random. The statement 'When not using the full keyspace, the key should be extremely random' is incorrect because it implies that not using the full keyspace is acceptable as long as the key is random. In practice, cryptographic keys should always use the full available keyspace AND be…

Submitted by andreas_gr· Apr 18, 2026Cryptography

Question

Options

AThe more a key is used, the shorter its lifetime should be.
BWhen not using the full keyspace, the key should be extremely random.
CKeys should be backed up or escrowed in case of emergencies.
DA key's lifetime should correspond with the sensitivity of the data it is protecting.

How the community answered

(14 responses)

A
7% (1)
B
86% (12)
C
7% (1)

Explanation

The statement 'When not using the full keyspace, the key should be extremely random' is incorrect because it implies that not using the full keyspace is acceptable as long as the key is random. In practice, cryptographic keys should always use the full available keyspace AND be randomly generated - reducing the keyspace weakens security regardless of randomness. The other statements are correct: high-frequency key use warrants shorter lifetimes (A), keys should be backed up or escrowed (C), and key lifetime should match data sensitivity (D).

Topics

#Key Management#Cryptography Principles#Key Lifetime#Key Randomness

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