フリー問題

問題文

A corporate headquarters asks why the fourth message exists at all if both ends can already compute the same key. Which pair states what its absence triggers and what the fourth message confirms?

選択肢

1. Both ends can already compute the same key after the second message, so the missing message triggers the timed rollover and the fourth message confirms the finished inspection inside that authentication handshake.
2. Both ends can already compute the same key after the second message, so the missing message triggers the timed retries and the fourth message confirms the finished installation inside that authentication handshake.
3. Both ends can already compute the same key after the second message, so the missing message triggers the timed retries and the fourth message confirms the finished inspection inside that authentication handshake.
4. Both ends can already compute the same key after the second message, so the missing message triggers the timed rollover and the fourth message confirms the finished installation inside that authentication handshake.