Prince Sultan University
College of Computer & Information Sciences
Department of Computer Science
CS391: Computer Security
Tutorial 3 2010
1- Using a block diagram, show the major components of a typical crypto system and
the parameters involved.
2- What are the major security problems solved by cryptography?
3- What is the major difference between symmetric and asymmetric cryptography?
4- What are the major characteristics of asymmetric keys?
5- Explain how confidentiality is maintained in asymmetric key systems.
6- Explain how a client may authenticate a server using public key cryptography (prove
the identity of the server, assuming that the public key of the server is known).
7- Explain how digital signatures may be implemented using public key cryptography.
8- What are the major types of cryptographic ciphers (algorithms)? Briefly describe each
of them.
9- Using a simple plaintext phrase and key, explain how transposition ciphers work.
10- Using transposition ciphers and the key “wisdom”, transform the sentence “public
key cryptography” into cipher text.
11- Explain how exponentiation ciphers work.
12- What is the major problem with symmetric key algorithms?
13- Explain how two users may establish a common symmetric key using the DiffieHellman algorithm.
14- Describe in detail the RSA public key cryptographic algorithm and state its main
properties.
15- What is the major problem with RSA and public key cryptography in general?