Fall 2001, CSE 597E: Quiz 5 - 14 Nov 2001

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  1. [2 points] The BAN Logic is (only one answer, please)

    1. An intuitionistic logic
    2. A linear logic
    3. A belief system
    4. A knowledge system

  2. [4 point] Which of the following are typical statements in BAN logic (mark all correct answers)

    1. P believes that X is fresh
    2. P transmits the information X at time t
    3. P believes that Q believes X
    4. P cannot be trusted

  3. [2 points] Which of the following is a characteristic of the BAN logic (only one answer, please)

    1. There is always an adversary
    2. There are always exactly two parties involved
    3. There is always a trusted third party which believes in the truth of all messages sent
    4. All the principals are honest, in the sense that they believe in the truth of the messages they send

  4. [2 points] What did the BAN logic help discovering in the case of the Needham-Schroeder protocol (only one answer, please)

    1. An implicit extra assumption (B assumes that the key he receives from A is fresh)
    2. An attack strategy (the attacker duplicates the message from A to B)
    3. The necessity of using a nonce
    4. The necessity of using a time stamp