Information security — Winter 2021

Define the following terms:

Non-repudiation (ii) Data integrity (iii) Confidentiality

Distinguish between passive and active security attacks? Define the type of Security attack in each of the following cases:

Astudent breaks into a professor’s office to obtain a copy of the next day’s test. (ii) Astudent gives a check for $10 to buy a used book. Later she finds that the check was cashed for $100. (iii) Astudent sends hundreds of e-mails per day to another student using a phony return e-mail address.

List and explain various block cipher modes of operation with the help of diagram.

What is the purpose of S-boxes in DES? Explain the avalanche effect.

Construct a Playfair matrix with the key “engineering”. And encrypt the message “test this Balloon”.

Let K = 133457799BBCDFF1 be the key in hexadecimal. Derive K1 the first round sub key using a single round version of DES. Permuted Choice One (PC-1) Permuted Choice Two (PC-2)

Let M =3243F6A8885A308D313198A2E0370734 be the plain text message and K=2B7E151628AED2A6ABF7158809CF4F3C be the key in hexadecimal. Perform the following operation using AES.

Add round key.

Shift row transformation on output of (a)

What is a nonce? What is the difference between a session key and a master key?1

Differentiate between hashing and encryption. What are the practical applications of hashing?

Explain Diffie Hellman key exchange algorithm with example.

What is public key cryptography? What are the principal elements of a public-key cryptosystem?

Perform encryption and decryption using the RSA algorithm for p=5, q=11, e=3, M=9.

What do you mean by key distribution? Give at least one method for key distribution with proper illustration.

Explain the triple DES scheme with two keys.

Differentiate between Conventional encryption and Public-key encryption.

Discuss X.509 Certificates.

Why not Double DES? What is a meet-in-the-middle attack?

Discuss message digest generation using SHA-512.

What is message authentication code? What is the difference between a Message authentication code and a one-way hash function? Write the basic uses of Message authentication code.

Encrypt the message “ Asymmetric key cryptography is fun” using Transposition cipher with key (3,2,6,1,5,4)

Write difference between (i) block cipher and stream cipher (ii) monoalphabetic cipher and polyalphabetic cipher

Discuss generic model of digital signature process.

Using the Viennese cipher, encrypt the word “explanation” using the key leg.

Discuss four general categories of schemes for the distribution of public keys.

Explain Kerberos in detail.