Which one of the following modes of operation in DES is used for operating short data?
a. Cipher Feedback Mode (CFB)
b. Cipher Block chaining (CBC)
c. Electronic code book (ECB)
d. Output Feedback Modes (OFB)
24.Symmetric Encryption is called
a. Conventional encryption
b. secret-key encryption
c. single-key encryption
d. all of the above
25.if the used key is 7 and the plain value is 14 , then the cipher value of Caesar algorithm (modular
value is 26 ) is:
a. 21
b. 7
c. 19
d. None
26.In point 25 , if the key is 19 , and the cipher word is lxgw, what is the plain word
a. Help
b. send
c. need
d. none
27.Providing diffusion across S-box inputs come from?
a. substitution
b. permutation
c. a+b
d. none
28.when we have a symmetric key of 32 bits size, the Number of Alternative Keys are:
d. none
29.in point 28 , the required time to find the key at 1 decryption/ mu s is:-
a. mu s
b. mu s
c. mu s
d. none
encrypts 64-bit data using 56-bit key
a. AES
b. DES
c. 3DES
d. none
23.Which one of the following modes of operation in DES is used for operating short data? a. Cipher Feedback Mode (CFB b.Cipher Block chaining (CBC)
C.
Electronic code book (ECB
d.Output Feedback Modes(OFB
24.Symmetric Encryption is called a. Conventional encryption C. single-key encryption
b. secret-key encryption d. all of the above
25.if the used key is 7 and the plain value is 14, then the cipher value of Caesar algorithm (modular value is 26) is:
a. 21 b. 7 c. 19 d. None 26.In point 25, if the key is 19, and the cipher word is Ixgw, what is the plain word a. Help b. send c. need d. none 27.Providing diffusion across S-box inputs come from? a. substitution b. permutation c. a+b d. none 28.when we have a symmetric key of 32 bits size, the Number of Alternative Keys are: a. b. c. d. none 29.in point 28, the required time to find the key at 1 decryption/s is:- a. us b. us c. uS d. none 30. encrypts 64-bit data using 56-bit key a. AES b. DES
c. 3DES
d. none