Question $32$

In exponentiation cipher, if the prime number is $5191831,$ then the letters in the message should be grouped in blocks of $m$ letters, where $m$ is:

a$.5$

b$.3$

c$.$ none of these options

d$.4$

e$.2$

Question $31$

the ciphertent, block i is the output block i xolted with the plaintext block i without encryption, this is done in the

mode of operation.

a$.$ Output feed back

b$.$ Cepher leed back

c$.$ Cipher block chaining.

d$.$ none of these

e counter

Question $30$

Nipe yet anowed Narked oun of $1,00$

the ciphertext block i is the encryption of plain text block i using the encryption key. this is done in the $\_\_$mode of operation.

a$.$ Cipher feed back

b$.$ none of these

e$.$ electronic codebook

d$.$ Cipher block chaining.

e$.$ Output leed back

Question $29$

Each message is segmented into blocks and each block is encrypted and sent to the other side. this mode of operation is :

a$.$ Cipher block chaining.

b$.$ none of these

c$.$ Cipher feed back

d$.$ electronic codebook

e$.$ Outout feed bock

Question $27$

Not jot antwaved Marked out of I. DC

The sises of the input key and the expanded key in AES are respectively:

a$.$ none of these options

b$.128$bit,$149$bit

c$.16$bit$176$bit

d$.4$ bits, $44$ bits

e$.4$ bytes, $44$ bytes

$1$