Preparing for your B.Tech Cryptography exam? Reviewing previous year objective questions is one of the best ways to test your knowledge.
Here is a collection of Multiple Choice Questions (MCQs) from past 7th and 8th-semester Cryptography (051718, 051818) exams.
B.Tech 7th Semester Special Exam, 2020 (Code: 051718)
- DES follows
- (i) hash algorithm
- (ii) Caesar cipher
- (iii) Feistel cipher structure
- (iv) SP-network
- Answer: (iii) Feistel cipher structure
- Find the solution of x^2 ≡ 16 mod 23.
- (i) x=6 and 17
- (ii) x=4 and 19
- (iii) x=11 and 12
- (iv) x=7 and 16
- Answer: (ii) x=4 and 19 (Calculation: (x-4)(x+4) ≡ 0 (mod 23). Since 23 is prime, x ≡ 4 or x ≡ -4 ≡ 19.)
- In SHA-512, the message is divided into blocks of size ___ bits for the hash computation.
- (i) 1024
- (ii) 512
- (iii) 256
- (ν) 1248
- Answer: (i) 1024
- When a hash function is used to provide message authentication, the hash function value is referred to as
- (i) message field
- (ii) message digest
- (iii) message score
- (iv) message leap
- Answer: (ii) message digest
- Which one of the following is not a public-key distribution means?
- (i) Public-key certificates
- (ii) Hashing certificates
- (iii) Publicly available directories
- (iv) Public-key authorities
- Answer: (ii) Hashing certificates
- The Data Encryption Standard (DES) was designed by
- (i) Microsoft
- (ii) Apple
- (iii) IBM
- (iv) None of the above
- Answer: (iii) IBM
- Which of the following encryption keys is used to encrypt and decrypt the data?
- (i) Public key
- (ii) Private key
- (iii) Symmetric key
- (iv) Asymmetric key
- Answer: (iii) Symmetric key
- In asymmetric key cryptography, the private key is kept by
- (i) sender
- (ii) receiver
- (iii) both sender and receiver
- (iv) all the connected devices to the network
- Answer: (ii) receiver
- Network layer firewall has two sub-categories as
- (i) statefull firewall and stateless firewall
- (u) bit-oriented firewall and byte-oriented firewall
- (ui) frame firewall and packet firewall
- (iv) None of the above
- Answer: (i) statefull firewall and stateless firewall
B.Tech 8th Semester Exam, 2017 (Code: 051818)
- (i) Transposition cipher involves
- a) Replacement of blocks of text with other blocks
- b) Replacement of characters of text with other characters
- c) Strictly row-to-column replacement
- d) Some permutation on the input text to produce cipher text
- Answer: d) Some permutation on the input text to produce cipher text
- (ii) Cryptanalyst is a person who
- a) devises cryptography solutions
- b) attempts to break Cryptography solutions
- c) none of these
- d) both of these
- Answer: b) attempts to break Cryptography solutions
- (iii) Block ciphers can be used as stream ciphers in
- a) ECB mode
- b) CBC mode
- c) OFB mode
- d) CFB & OFB mode
- Answer: d) CFB & OFB mode
- (iv) When two different message digests have the same value, it is called as
- a) Attack
- b) Collision
- c) Hash
- d) None of these
- Answer: b) Collision
- (v) Avalanche Effect in block ciphers means
- a) All bits of the ciphertext needs to be independent on the plaintext
- b) Small change in plaintext should create significant change in ciphertext
- c) Ciphertext only depend on most significant bits of plaintext
- d) None of the above
- Answer: b) Small change in plaintext should create significant change in ciphertext
- (vi) Which of the following is independent malicious program that need not any host program?
- a) Trap doors
- b) Trojan horse
- c) Virus
- d) Worm
- Answer: d) Worm
- (vii) In RSA, given n=221, e=5, the value of d is
- a) 54
- b) 87
- c) 77
- d) None of the above
- Answer: c) 77 (Calculation: n = 13 * 17. phi(n) = (13-1)(17-1) = 12 * 16 = 192. Find d where 5 * d ≡ 1 (mod 192). d = 77.)
- (viii) While creating Digital Envelop, we encrypt one time session key with
- a) Senders private key
- b) Sender public key
- c) Sender master key
- d) Receiver’s public key
- Answer: d) Receiver’s public key
- (ix) Kerberos is an authentication protocol which includes
- a) Password based authentication
- b) Challenge Response based authentication
- c) OTP based authentication
- d) None of the above
- Answer: a) Password based authentication
- (x) The SSL record protocol in SSL provides two services
- a) Confidentiality & integrity
- b) Integrity and authentication
- c) nonrepudiation and confidentiality
- d) None of the above
- Answer: a) Confidentiality & integrity
B.Tech 7th Semester Special Exam, 2016 (Code: 051718)
- (a) By encryption of a text we mean
- (i) compressing it
- (ii) scrambling it to preserve its security
- (iii) expanding it
- (iv) hashing it
- Answer: (ii) scrambling it to preserve its security
- (b) In public key encryption if A wants to send and encrypted message
- (i) A encrypts message using his private key
- (ii) A encrypts message using B’s private key
- (iii) A encrypts message using B’s public key
- (iv) A encrypts message using his public key
- Answer: (iii) A encrypts message using B’s public key
- (c) A digital signature is
- (i) a bit string giving identity of a correspondent
- (ii) a unique identification of a sender
- (iii) an encrypted signature of a sender
- (iv) an authentication of an electronic record by tying it uniquely to a key only a sender knows.
- Answer: (iv) an authentication of an electronic record by tying it uniquely to a key only a sender knows.
- (d) The Secure Electronic Transaction protocol is used for
- (i) credit card payment
- (ii) cheque payment
- (iii) electronic cash payments
- (iv) payment of small amounts internet services
- Answer: (i) credit card payment
- (e) Which of the following security properties does an S-Box provide?
- (i) Diffusion
- (ii) Integrity
- (iii) Malleability
- (iv) Confusion
- Answer: (iv) Confusion
- (f) Disclosure is a threat against which security goal?
- (i) Confidentiality
- (ii) Integrity
- (iii) Assurance
- (iv) Availability
- Answer: (i) Confidentiality
- (g) Which of the following encryption modes suffer from malleability attacks?
- (i) Counter CBC-MAC (CCM)
- (ii) Cipher Block Chaining (CBC)
- (iii) Offset Code Book (OCB)
- (iv) Electronic Code Book(ECB)
- Answer: (iv) Electronic Code Book(ECB)
- (h) A way of verifying both the sender of information and the integrity of a message is through the use of
- (i) Private key encryption
- (ii) digital signatures
- (iii) Public key encryption
- (iv) digital certificates
- Answer: (ii) digital signatures
- (i) A(n)…………… is a key less substitution cipher with N inputs and M outputs that uses a formula to de fine the relationship between the input stream and output stream.
- (i) S-Box
- (ii) P-Box
- (iii) T-Box
- (iv) None of these
- Answer: (i) S-Box
- (j) SSL provides only
- (i) integrity
- (ii) confidentiality
- (iii) authentication
- (iv) durability
- Answer: (Note: This is a flawed question as SSL provides confidentiality, integrity, and authentication. Based on the options, (ii) confidentiality is a primary service.)
B.Tech 7th Semester Exam, 2015 (Code: 051718)
- (a) In cryptography, what is cipher?
- (i) Algorithm for performing encryption and decryption
- (ii) Encrypted message
- (iii) Both (i) and (ii)
- (iv) None of the above
- Answer: (i) Algorithm for performing encryption and decryption
- (b) In cryptography, the order of the letters in a message is rearranged by
- (i) transpositional ciphers
- (ii) substitutional ciphers
- (iii) Both (i) and (ii)
- (iv) None of the above
- Answer: (i) transpositional ciphers
- (c) Cryptanalysis is used
- (i) to find some insecurity in a cryptographic scheme
- (ii) to increase the speed
- (iii) to encrypt the data
- (iv) None of the above
- Answer: (i) to find some insecurity in a cryptographic scheme
- (d) Which one of the following is a cryptographic protocol used to secure HTTP connection?
- (i) Stream control transmission protocol (SCTP)
- (ii) Transport layer security (TLS)
- (iii) Explicit congestion notification (ECN)
- (iv) Resource reservation protocol
- Answer: (ii) Transport layer security (TLS)
- (e) What is data encryption standard (DES)?
- (i) Block cipher
- (ii) Stream cipher
- (iii) Bit cipher
- (iv) None of the above
- Answer: (i) Block cipher
- (f) Cryptographic hash function takes an arbitrary block of data and returns
- (i) fixed-size bit string
- (ii) variable-size bit string
- (iii) Both (i) and (ii)
- (iv) None of the above
- Answer: (i) fixed-size bit string
- (g) Which of the following algorithms belongs to asymmetric encryption?
- (i) 3-DES
- (ii) RC5
- (iii) IDEA
- (iv) RSA
- Answer: (iv) RSA
- (h) Which is the largest disadvantage of the symmetric encryption?
- (i) More complex and therefore more time-consuming calculations
- (ii) Problem of the secure transmission of the secret key
- (iii) Less secure encryption function
- (iv) Is not used anymore
- Answer: (ii) Problem of the secure transmission of the secret key
- (i) Which of the following statements is correct?
- (i) PGP uses asymmetric encryption
- (ii) In the World Wide Web, primarily symmetric encryption is used
- (iii) PGP uses combined encryption
- (iv) None of the above
- Answer: (iii) PGP uses combined encryption
- (j) In which way does the combined encryption combine symmetric encryption and asymmetric encryption?
- (i) First, the message is encrypted with symmetric encryption…
- (ii) The secret key is symmetrically transmitted, the message itself asymmetrically
- (iii) First, the message is encrypted with asymmetric encryption…
- (iv) The secret key is asymmetrically transmitted, the message itself symmetrically
- Answer: (iv) The secret key is asymmetrically transmitted, the message itself symmetrically