A permanent key, in the key-distribution scheme covered in this lesson, is used for what purpose?

Answer

To distribute session keys between two entities

Options - A. To distribute session keys between two entities - B. To encrypt user data for the duration of one connection - C. To identify which entity is the key distribution center - D. To label a symmetric key as opposed to an asymmetric one Why - A. Correct — a permanent key exists specifically so that fresh session keys can be handed out under it, session after session. - B. That is what a SESSION key does. The permanent key’s job is one level up: getting session keys safely to each end. - C. That is a role held by the KDC, which is an ENTITY, not a key. Naming the entity is a category error when the question asks for a key. - D. "Symmetric key" names the whole family this key belongs to. It says nothing about the role this particular key plays.

SB5e ch2 §2.2, §2.4; ch20 §20.5–20.6; NIST SP 800-38A