CS3730 Midterm Review 1. List the passive attacks and active attacks 2. List the two basic operations in classical cryptography. 3. The following cipher text is encrypted by Caesar Cipher, decrypt it and get the original plain text.

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Nov 21, 2013 (3 years and 8 months ago)

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CS3730 Midterm Review


1.

List the passive attacks and active attacks


2.

List the two
basic
operations in classical cryptography.


3.

The following cipher text is encrypted by
Caesar Cipher, decrypt it and get the original plain
text.

Xfctfdvsjuz


4.

The following cipher text is encrypted by
Caesar Cipher, decrypt it and get the original plain
text.

pqxoqqlcfiifkqebmixfkqbub


5. Draw a figure to illustrate the steps in one round of DES.


6. Draw figures to illustrate the encryption procedure
in ECB, CBC, CFB,
OFB,
and CTR modes
of operations.
Which modes used in block cipher and which modes used in stream

cipher?




7.
What is the Fermat’s Theorem?



8
. Define the Euler’s Totient Function.



9
. Calculate dlog
2, 19

7




10
. Calculate


Ǿ(15)


11.

What is the Euler’s Theorem?



12
. List the messages and destinations transmitted in the Key

Distribution Scenario.



1
3
. Draw a figure to illustrate the ANSI X9.17 PRNG


14.
Proof Ǿ(pq)= Ǿ(p) Ǿ(q), p and q are prime numbers.


15. Can you recover the original message
in the CFB (Cipher Feed Back) mode
if the IV is lost
in the receiver side?