Fall 2001, CSE 597E: Quiz 7 and solution - 21 Nov 2001

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  1. [1 points] What is the problem of secure multi-party computation?

    The problem of secure multi-party function computation is as follows: n players, P1, P2, Pn, wish to evaluate a function , F(x1,x2,...,xn), where xi is a secret value provided by Pi. The goal is to preserve the privacy of the player's inputs and guarantee the correctness of the computation.

  2. [4 point] Which of the following techniques can help to force a semi-honest behavior? (mark all those which apply)

    1. Commitment schemes with strong 0-knowledge proofs
    2. Involvement of a trusted third party
    3. Coin generation
    4. Protocol emulation (to authenticate the computation)

  3. [2 points] What kind of information does the basic construction of block encryption reveal: (only one answer, please)

    1. The operation used to perform the encryption
    2. The attempt of an attacker to decrypt it
    3. The presence of an attacker
    4. The length of the plaintext

  4. [3 points] What is the difference between a plaintext attack and a cyphertext attack?

    In the first case the attacker tryes to get information about the encryption function by sending plaintext and by looking at the result of the encryption. In the second case the attacker sends cyphertext and looks at the result of the decryption.

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