Which should be kept as a secret in public key cryptosystem?
  • a) Encryption key
  • b) Decryption key
  • c) Encryption & Decryption key
  • d) None of the mentioned
Cipher system can be solved effectively by statistically using
  • a) Time of occurrence
  • b) Frequency of occurrence
  • c) Length of the message
  • d) None of the mentioned
Encryption transformations are known as
  • a) Diffusion
  • b) Confusion
  • c) Diffusion & Confusion
  • d) None of the mentioned
For n input bits the number of substitution patterns are
  • a) 2n
  • b) (2n)!
  • c) 1/2n!
  • d) 2n!
In transposition, the plaintext letters are
  • a) Substituted
  • b) Rearranged
  • c) Removed
  • d) None of the mentioned
The substitution of the letters are done
  • a) Serially
  • b) Parallel way
  • c) Serially & Parallel way
  • d) None of the mentioned
In cipher feedback method, encryption is done on
  • a) Single individual bits
  • b) Characters
  • c) Single individual bits & Characters
  • d) None of the mentioned
In stream encryption, the key sequence repeats itself.
  • a) True
  • b) False
In which method, key-stream is generated independently?
  • a) Synchronous
  • b) Self synchronous
  • c) Synchronous & Self synchronous
  • d) None of the mentioned
Synchronous ciphers uses
  • a) Confusion
  • b) Diffusion
  • c) Confusion & Diffusion
  • d) None of the mentioned
Public key cryptosystem uses same key for both encryption and decryption.
  • a) True
  • b) False
Public key cryptosystem is also known as
  • a) One way function
  • b) Two way function
  • c) Feedback function
  • d) None of the mentioned
Euler’s totient function is determined by
  • a) pq
  • b) (p-1)(q-1)
  • c) (p+1)(q+1)
  • d) p/q
0 h : 0 m : 1 s