WorksheetsMCQs on Lightweight Cryptography (from 5.2.2 content)
Total questions: 30
Worksheet time: 11mins
What is the main purpose of Lightweight Cryptography (LWC)?
To make cryptography weaker
To design ciphers for constrained devices
To replace AES completely
To remove encryption entirely
Which technology development has increased the need for lightweight cryptography?
Cloud computing
Blockchain
Internet of Things (IoT)
Artificial Intelligence
What kind of devices is LWC mainly designed for?
Supercomputers
Smartphones
Smart objects with limited resources
Desktop computers
Which of the following is NOT a constraint in IoT devices?
Low computation
High memory
Limited battery
Small storage
The term "lightweight" in LWC means:
Low security
Small footprint and low power consumption
Fast only in hardware
Low key length only
Which standard cryptographic algorithm is often inefficient for IoT devices?
RSA
AES
DES
Blowfish
In symmetric-key cryptography, the same key is used for:
Encryption only
Decryption only
Both encryption and decryption
Key exchange
Block ciphers work on:
Continuous bit streams
Fixed-size groups of bits
One character at a time
Random-length messages
A stage in each round of PRESENT?
Feistel function
Diffusion layer
Substitution layer
Initial permutation
What is the full form of TEA?
TEA operates on two 32-bit unsigned integers derived from:
64-bit data block
128-bit data block
16-bit data block
256-bit data block
Which operations does TEA mainly use?
Multiplication, division, and modulo
Addition, XOR, and shifts
Permutation, inversion, and rotation
Exponentiation, hashing, and masking
XTEA is an improved version of TEA because it fixes:
Key collision issue
Equivalent key problem
Slow speed issue
Block size limitation
Which of the following is NOT a variant of the TEA family?
XXTEA
Tiny XTEA
Block TEA
PRESENT
The Scalable Encryption Algorithm (SEA) is designed for:
Large data centers
Small embedded applications
Banking servers
Cloud storage
What is a unique feature of SEA?
Fixed key size
On-the-fly key derivation
No round structure
Uses lookup tables
In SEA, the plaintext size, key size, and processor size must satisfy:
n = 8b
n = 6b
n = b^2
n = 2b
What is the main disadvantage of SEA?
Very high cost
Trades space for time
Complex operations
Weak substitution layer
Which cipher is based on substitution–permutation network (SPN)?
HIGHT
PRESENT
TEA
SEA
How many rounds does PRESENT perform?
30
32
31
64
What is the Block size of PRESENT ?
64 bits
80 bits
128 bits
Which of the following operations is part of the PRESENT algorithm's stages?
Multiplication and inversion
XOR key mixing and permutation layer
Hashing and padding
Division and rotation
The HIGHT encryption algorithm uses:
Substitution-permutation network
Generalized Feistel network
Linear feedback shift register
Stream generation
HIGHT uses which simple operations?
XOR, addition mod 2^8, and bitwise rotation
Division, exponentiation, and modulo
Substitution and compression
Hashing and padding
Lightweight ciphers are mainly preferred when:
Large-scale encryption is required
High performance outweighs cost
Cost and energy efficiency are more important than speed
Security level must be maximum
Which ISO standard names PRESENT as LWC?
NIST SP 800-38A
ISO/IEC 29192-2:2012
ISO/IEC 15408-1:2009
AES
Stream ciphers encrypt
One bit or byte at a time
large blocks
only files
key schedule
Main advantage of TEA family:
Very small code size and simple operations
Uses S-boxes
Variable block size
Variable block size
Why LWC is not meant to replace AES globally?
Intended only for constrained devices
AES is weaker
LWC gives higher throughput
AES has smaller cost
How many rounds are used in HIGHT cipher?
32
64
25
48
