TU Wien:Network Security VU (Zseby)/Exam 2016-04-26 (SS16)

15 questions on 9 pages, 1 hour of time

1) What is the difference between viruses and worms?

2) Explain SYN floods

3) Decrypt this message (Ceasar cipher, k=3). _ _ _ _ _ _

4)

5) How does a One-Time-Pad work? Calculate the ciphertext for this message and key.

6) Why is it a bad idea to use a One-Time-Pad twice?

7) 3DES with encryption function E(D(E(m,k1),k2),k3) - why not E(E(E(m,k1),k2),k3)?

8) (Drawing of ECB given) What can be used in an attack of ECB-encrypted messages?

9) Explain the Known-plaintext attack.

10) What are the encryption and decryption functions for RSA?

11) a) Calculate the advantage for P(A(R) = 1) = 0.9 and P(A(G(s)) = 1) = 0.2

b) Can G be considered as a good PRG?

12) What function can be used to find out how many numbers 1 <= x <= n are relatively prime to n?

Calculate for a given n, calculate for a product of two factors.

13) What is the purpose of Support Vector Machines (SVMs)?

14) What can be done if you only have a technique to learn a linear classifier but the data is not linear separable?

15) What is the darkspace?