WorksheetsSecurity Concepts Quiz
Total questions: 100
Worksheet time: 1hrs 15mins
Which of the following is not a security goal?
Confidentiality
Integrity
Accessibility
Availability
The OSI Security Architecture was developed by:
ISO
IEEE
NIST
ITU
Security mechanisms aim to:
Cause security attacks
Detect and prevent attacks
Replace security policies
Disable cryptography
Which is not a category of security services?
Authentication
Access Control
Phishing
Confidentiality
An active attack attempts to:
Monitor the system
Modify or disrupt operations
Backup data
Encrypt communication
Passive attacks include:
Masquerade
Eavesdropping
Replay
Modification
A model for network security involves:
Sender, Receiver, and Attacker
Algorithms only
Firewall only
Only symmetric key usage
Authentication ensures:
User is who they claim to be
Data is compressed
File format is correct
Data is always available
Data integrity ensures:
Data can be replayed
Data is not altered
Data is compressed
Data is invisible
Availability ensures:
Service is denied
Systems are offline
Data is usable on demand
Data is encrypted
Which mechanism is used for secure exchange of keys?
Digital watermarking
Cryptanalysis
Key management
Steganography
Which is a security attack?
User authentication
Encryption
Replay
Key distribution
Masquerade attack involves:
Encrypting data
Pretending to be another user
Stealing hardware
Using long passwords
Traffic analysis is a:
Passive attack
Active attack
Key exchange
Authentication method
Which of the following is not a security service?
Non-repudiation
Availability
Firewalls
Confidentiality
End-to-end security is provided by:
OSI model
Transport layer
Data link layer
Application layer
Security attacks can be categorized into:
Software and Hardware
Logical and Physical
Passive and Active
Single and Multiple
Security mechanisms aim to enforce:
Security goals
Cost reductions
Large file storage
Download speed
Replay attack involves:
Deleting old messages
Sending data in real-time
Resending valid data maliciously
Creating new messages
Symmetric encryption uses:
Same key for encryption and decryption
Different keys
No key
Public key only
Substitution technique replaces:
Key with text
Plaintext with ciphertext
Files with folders
Ciphertext with plaintext
Which cipher uses substitution?
Rail Fence
Caesar Cipher
One-Time Pad
Vigenère Cipher
In transposition cipher:
Characters are replaced
Order is rearranged
Data is hashed
Stego image is created
Steganography is the art of:
Encrypting data
Hiding information
Hashing data
Decrypting messages
The Caesar cipher shifts letters by:
1
2
3
5
Playfair cipher encrypts:
Single characters
Blocks of 3 characters
Digraphs (pairs)
Full sentences
Rail fence cipher is an example of:
Steganography
Transposition
Hashing
Monoalphabetic substitution
A symmetric cipher model includes:
Public key
Encryption and decryption using same key
Compression
Keyless transformation
The number of possible keys in ceaser cipher is:
26
26!
2^26
100
Block cipher encrypts data in:
Single bits
Variable-length blocks
Fixed-size blocks
Continuous streams
Feistel structure is used in:
Stream ciphers
DES
AES
RSA
In Feistel structure, encryption and decryption algorithms are:
Different
Same
Useless
Only symmetric
A round function in block cipher is used to:
Decrypt only
Add noise
Combine plaintext and key
Hash plaintext
Which is not a feature of block cipher?
Deterministic output
Padding requirement
Stream-based operation
Fixed-size processing
Block cipher provides:
Lossless compression
Only authentication
Data confidentiality
Digital signature
Which of the following is not a block cipher mode of operation?
CBC
ECB
CFB
RSA
ECB mode stands for:
Encrypted Cipher Bit
Electronic Cipher Block
Electronic Code Book
Encoded Control Block
Which mode of operation uses chaining?
ECB
CBC
OFB
CTR
Block cipher modes are used to:
Change file format
Generate plaintext
Encrypt long messages
Break the cipher
In CBC, the first block is XORed with:
Last ciphertext
Initialization Vector (IV)
Public key
Round key
The function used to convert plaintext into ciphertext in block cipher is called:
Transformation function
Decryption
Round shift
Compression
DES uses a block size of:
56 bits
64 bits
128 bits
32 bits
DES uses a key of length:
64 bits
56 bits
128 bits
512 bits
How many rounds are in DES encryption?
8
10
16
20
DES is based on:
Vigenère structure
Feistel structure
Hill cipher
LFSR
Initial permutation in DES is performed on:
Key
Plaintext
Ciphertext
Round function
The expansion function in DES expands 32-bit input to:
48 bits
64 bits
56 bits
32 bits
S-boxes in DES perform:
Key scheduling
Substitution
Permutation
Hashing
Key schedule in DES generates:
10 round keys
12 round keys
16 round keys
8 round keys
The final stage of DES includes:
Initial permutation
Expansion
Substitution
Inverse initial permutation
DES is vulnerable to:
Brute force
SQL injection
IP spoofing
Ping of death
Which of the following is true about DES?
Uses public key
Works on stream data
Uses symmetric key
Designed for digital signatures
Which of the following is true about DES?
Uses public key
Works on stream data
Uses symmetric key
Designed for digital signatures
Which is not a step in DES round function?
Expansion
Substitution
Compression
Permutation
DES encrypts data in:
Streams
Characters
64-bit blocks
ASCII values
The function f in DES operates on:
32-bit and 56-bit inputs
32-bit input and 48-bit key
64-bit input and 32-bit key
48-bit input and 64-bit key
Which permutation is used at the end of DES?
Initial permutation
Key permutation
Inverse initial permutation
Subkey permutation
DES key actually has 64 bits, but only 56 are used. The rest are:
Redundant
Check bits (parity)
S-box values
Permuted
A major weakness of DES is its:
High memory usage
Small key size
Lack of substitution
Use of XOR
Which algorithm replaced DES as the new standard?
RSA
Blowfish
AES
RC4
AES supports key sizes of:
64, 128, 192
128, 192, 256
128, 256, 512
56, 64, 128
AES block size is:
64 bits
128 bits
192 bits
256 bits
AES is based on:
Feistel structure
Substitution-permutation network
Hashing
Modular arithmetic
AES uses how many rounds for 128-bit key?
10
12
14
16
SubBytes operation uses:
S-box substitution
Permutation table
XOR
Key scheduling
MixColumns operation affects:
Rows
Columns
Bytes
Bits
ShiftRows transformation performs:
Row reversal
Row shifting
Row permutation
Row substitution
The number of rounds for AES-256 is:
10
12
14
16
Which transformation is not used in the final round of AES?
SubBytes
ShiftRows
AddRoundKey
MixColumns
AES was developed under the direction of:
ISO
IEEE
NIST
NSA
AES is a:
Public-key cipher
Symmetric block cipher
Hash function
Steganographic method
AES is considered secure due to:
Use of Feistel rounds
Large key size and rounds
Use of XOR
Fixed output
AES operates on a matrix called:
Plaintext grid
State array
Byte block
Crypto pad
The basic unit of AES internal data representation is:
Bit
Nibble
Byte
Word
In AES, round keys are derived from:
Plaintext
Ciphertext
Original encryption key
S-box
AES standard was established in:
1995
1997
2001
2005
AES is efficient in both:
Hardware and software
Streaming and routing
Compression and expansion
Analysis and design
MixColumns in AES involves:
XOR operation
Matrix multiplication in GF(2^8)
Bit shifting
Key replacement
In AES, the initial AddRoundKey is applied to:
S-box
Round key
State
Ciphertext
AES security is improved over DES because of:
Smaller key
Fewer rounds
No initial permutation
Larger key size and resistance to known attacks
Which of the following ensures that a sender cannot deny having sent a message?
Integrity
Authentication
Non-repudiation
Confidentiality
Which term refers to the ability to recover from hardware or software failure?
Confidentiality
Availability
Integrity
Reliability
Which of these is not a passive attack?
Eavesdropping
Traffic analysis
Interruption
Monitoring
Which of the following security principles deals with protecting data from unauthorized access?
Integrity
Confidentiality
Authentication
Non-repudiation
Which security mechanism is specifically designed to protect data in transmission?
Cryptographic algorithms
Biometric authentication
Anti-virus software
Logging and auditing
In a Caesar cipher, what is the key?
The number of positions to shift
A keyword
A set of primes
An S-box
Which cipher uses a matrix and digraphs for encryption?
Vigenère cipher
Caesar cipher
Playfair cipher
Monoalphabetic cipher
What is the main limitation of classical encryption techniques?
They are too slow
They require asymmetric keys
They are easily broken with modern tools
They cannot be implemented on hardware
Steganography hides data in:
Encrypted emails
Hash values
Images, audio, or video
Web traffic logs
DES performs how many total permutations?
1
2
3
4
Which part of the DES algorithm performs bit rearrangement?
S-box
P-box
K-box
E-box
What is the result of the expansion function in DES?
56-bit output
32-bit output
48-bit output
64-bit output
Which of the following algorithms is now considered insecure for sensitive data?
AES
DES
Blowfish
RC6
Which AES transformation substitutes each byte with a corresponding value from a fixed table?
SubBytes
MixColumns
ShiftRows
AddRoundKey
Which step is applied in every round of AES?
AddRoundKey
MixColumns
SubBytes
All of the above
AES is designed to work efficiently on:
Only hardware
Only software
Both hardware and software
Only mobile devices
In which block cipher mode do identical plaintext blocks produce identical ciphertext blocks?
CBC
ECB
CFB
OFB
What is the purpose of an Initialization Vector (IV)?
Increase block size
Encrypt plaintext
Prevent repetition in encryption
Perform key expansion
CTR mode uses:
Stream of IVs
A counter with encryption
XOR with previous ciphertext
Manual padding
In which mode does a single bit error in ciphertext affect only one block of plaintext?
CBC
ECB
CTR
CFB
