Question 1
(a)
List and explain any three active attack?.
3 Marks
(b)
Discuss security of Hill cipher.
4 Marks
(c)
Compare Counter and Cipher Block Chaining mode of operation used for encryption and decryption.
7 Marks
Gujarat Technological UniversitySummer 2026 Examination
GTU 3170720 Information security (IS) Summer 2026 Paper Solution & PDF
B.E. · Computer Engineering · Semester 7 · Subject Code: 3170720
Total Marks70 MarksExternal theory exam
Passing Marks23 Marks33% minimum cutoff
Exam Duration2.5 Hours2:30 PM – 5:00 PM
Paper Structure5 QuestionsWith internal OR choices
Question 2
(a)
Define Confusion and Diffusion
3 Marks
(b)
Draw the operation performed in one round of DES encryption.
4 Marks
(c)
With the help of diagram explain decryption of DES.
7 Marks
OR OPTION
(c)
Compare DES, Double DES and Triple DES.
7 Marks
Question 3
(a)
What is symmetric cipher? List requirements for it.
3 Marks
(b)
In RSA algorithm if p = 7, q = 11 and e = 13 then what will be the value of d?
4 Marks
(c)
With the help of diagram explain use of RSA algorithm for confidentiality and authentication.
7 Marks
OR OPTION
(a)
List applications of RSA algorithm.
3 Marks
(b)
What is trap door one way function? Give example.
4 Marks
(c)
Discuss the fast and efficient algorithm use for exponentiation in RSA.
7 Marks
Question 4
(a)
What is hash function? How it helps to protect integrity of a message?
3 Marks
(b)
Compare strong and weak hash function.
4 Marks
(c)
Draw and explain round function of SHA512 algorithm
7 Marks
OR OPTION
(a)
List applications of Cryptographic Hash Function
3 Marks
(b)
Discuss Birth day attack.
4 Marks
(c)
Discuss the security of MAC algorithm
7 Marks
Question 5
(a)
Explain signing in DSA algorithm.
3 Marks
(b)
How signature can be verified in ElGamal digital signature
4 Marks
(c)
List various alternatives used for key distribution in symmetric key cryptography. Also discuss the issue with key distribution.
7 Marks
OR OPTION
(a)
Discuss generation of a private/public key pair in Schnorr digital signature
3 Marks
(b)
Draw the model for Digital Signature.
4 Marks
(c)
With the help of diagram explain the two alternatives used for placement of encryption/decryption.
7 Marks
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About this Examination Paper & Attribution
Official Gujarat Technological University (GTU) examination paper and step-by-step solutions for Information security (IS) (Summer 2026, B.E. · Computer Engineering, Sem 7). Features complete 70-mark regular & remedial examination pattern, official marking distribution across all 5 questions, and direct 1-click official PDF download.
Transcribed for student exam preparation from Gujarat Technological University official examination archives. Questions, syllabus guidelines, and curriculum marking schemes remain the intellectual property of Gujarat Technological University.