In DES, the effective key length is:

• (a) 56 bits
• (b) 64 bits
• (c) 112 bits
• (d) 128 bits

DES encrypts data in blocks of:

• (a) 32 bits
• (b) 56 bits
• (c) 64 bits
• (d) 128 bits

DES stands for:

• (a) Data Encryption Standard
• (b) Digital Encryption Standard
• (c) Data Encryption System
• (d) Digital Encryption System

DES consists of:

• (a) 8 rounds
• (b) 12 rounds
• (c) 16 rounds
• (d) 32 rounds

DES is based on which network structure?

• (a) RSA Network
• (b) Feistel Network
• (c) SPN only
• (d) Diffie–Hellman Network

The length of each DES round key is:

• (a) 32 bits
• (b) 48 bits
• (c) 56 bits
• (d) 64 bits

Why is DES considered insecure today?

• (a) Small block size only
• (b) Weak hash function
• (c) Short effective key length allows brute-force attacks
• (d) It cannot decrypt ciphertext

Triple DES improves security primarily by:

• (a) Increasing the block size
• (b) Applying DES three times with multiple keys
• (c) Using public-key encryption
• (d) Replacing the Feistel network

The commonly used Triple DES operation is:

• (a) Encrypt–Encrypt–Encrypt
• (b) Encrypt–Decrypt–Encrypt
• (c) Decrypt–Encrypt–Decrypt
• (d) Encrypt–Hash–Encrypt

Compared with DES, Triple DES is: