CLASS TEST 1 NUMBER THEORY AND CRYPTOGRAPHY

In the Hill Cipher, which of the following conditions must be satisfied by the key matrix to ensure decryption is possible for all possible plaintexts and ciphertexts?

• The determinant of the key matrix must be non-zero.
  

• The key matrix must be invertible.

• The key matrix must be symmetric.

• The key matrix must have a determinant of 1.

Euler's Totient Function (φ(n)) returns the count of positive integers that are:

• Less than n and coprime to n.
  

• Divisible by n

• Prime and less than n.

• Even and less than n.

What is the value of φ(240)?

Fermat's Little Theorem states that if p is a prime number and a is an integer not divisible by p, then:

• a^(p - 1) ≡ 1 (mod p)
  

• a^p ≡ 1 (mod p)
  

• a^(p + 1) ≡ 0 (mod p)
  

• a^(p - 1) ≡ 0 (mod p)

  
  

If p is a prime number, what is the value of φ(p) according to Fermat's Little Theorem?

• 0

• 1

• P

• P-1

Lucas is concerned about potential cyberattacks that could disrupt his online services and cause downtime. Which basic cryptographic concept should he focus on to enhance the resilience of his systems?

• Confidentiality

• Integrity

• Availability

• NONE OF THE GIVEN OPTION

Liam is concerned that his data might be modified by malicious actors during transmission. Which basic cryptographic concept would help ensure that his data remains unaltered?

• Confidentiality

• Integrity

• Availability

Which of the following principle of cryptography explains transmitted data in cannot be denied from being accepted the message received?

• Privacy

• Integrity

• Non-repudiation

  
  

• Authentication

Using play fair cipher algorithm ,

plain text : instruments

key: monarchy

what will be its cipher text ?

Which of the following is not a type of poly alphabetic cipher?

• Rotor cipher

  
  

• Hill cipher

  
  

• One time pad cipher

  
  

• Multiplicative cipher