Question#1
The Vigenère cipher is a method of encrypting alphabetic text using _____?
a) a simple form of polyalphabetic substitution ✅ - Answer
b) a complex form of monoalphabetic substitution
c) a binary substitution method
d) a hexadecimal substitution method

Question#2
The Vigenère table used for encryption and decryption is also known as _____?
a) the tabula recta ✅ - Answer
b) the cipher square
c) the encryption matrix
d) the decryption grid

Question#3
In the Vigenère cipher, the key is repeated circularly until it matches the _____?
a) length of the plain text ✅ - Answer
b) length of the cipher text
c) number of alphabets used
d) size of the Vigenère table

Question#4
The algebraic formula for encryption in the Vigenère cipher when the table is not given is _____?
a) ei = (pi + ki) mod 26 ✅ - Answer
b) ei = (pi - ki) mod 26
c) ei = (pi * ki) mod 26
d) ei = (pi / ki) mod 26

Question#5
The One-Time Pad algorithm is considered unbreakable because it is _____?
a) completely secure ✅ - Answer
b) based on simple substitution
c) easy to implement
d) uses a fixed key length

Question#6
In the One-Time Pad algorithm, the key length must be equal to the _____?
a) length of the plain text ✅ - Answer
b) length of the cipher text
c) number of alphabets used
d) size of the encryption table

Question#7
The Hill cipher uses an area of mathematics called _____ for encryption?
a) linear algebra ✅ - Answer
b) differential calculus
c) integral calculus
d) probability theory

Question#8
In the Hill cipher, the plain text is converted into _____ for encryption?
a) vector form ✅ - Answer
b) matrix form
c) binary form
d) hexadecimal form

Question#9
The Rail Fence cipher is a type of _____ technique?
a) transposition ✅ - Answer
b) substitution
c) binary encryption
d) hexadecimal encryption

Question#10
In the Rail Fence cipher, the plain text is written in a _____ manner?
a) zig-zag ✅ - Answer
b) straight line
c) circular
d) spiral

Question#11
A digital signature confirms the _____ of the message?
a) integrity ✅ - Answer
b) length
c) speed
d) color

Question#12
Digital signatures use a form of _____ to ensure security?
a) cryptography ✅ - Answer
b) compression
c) encoding
d) decoding

Question#13
The sender computes a message digest and then encrypts it with their _____ to form a digital signature?
a) private key ✅ - Answer
b) public key
c) shared key
d) session key

Question#14
The receiver decrypts the digital signature with the _____ of the sender?
a) public key ✅ - Answer
b) private key
c) shared key
d) session key

Question#15
A digital signature must be part of the _____ to be most effective?
a) application data ✅ - Answer
b) message header
c) message footer
d) encryption key

Question#16
The Hill cipher requires the user to have an elementary understanding of _____?
a) matrices ✅ - Answer
b) graphs
c) trees
d) linked lists

Question#17
In the Hill cipher, the key matrix must be _____ for decryption?
a) inverted ✅ - Answer
b) transposed
c) multiplied
d) added

Question#18
The Rail Fence cipher derives its name from how it is _____?
a) encoded ✅ - Answer
b) decoded
c) encrypted
d) decrypted

Question#19
In the Rail Fence cipher, the cipher text is prepared by combining the individual _____?
a) rows ✅ - Answer
b) columns
c) diagonals
d) circles

Question#20
A digital signature is equivalent to a personal signature on a _____?
a) written document ✅ - Answer
b) digital image
c) audio file
d) video file