Exploring DES and AES in Cryptography

What does DES stand for?

• Data Encryption Service

• Data Encoding Standard

• Data Encryption Standard

• Digital Encryption System

Which of the following is a key feature of AES?

• Variable block size of 128 bits

• Fixed block size of 128 bits and variable key sizes (128, 192, 256 bits)

• Supports only 64-bit encryption

• Fixed key size of 256 bits only

How many rounds does DES use for encryption?

• 20

• 12

• 16

• 8

What is the block size of AES?

• 192 bits

• 128 bits

• 256 bits

• 64 bits

Which algorithm is considered more secure, DES or AES?

• RSA

• RC4

• AES

• Blowfish

What is the maximum key length for AES?

• 128 bits

• 192 bits

• 512 bits

• 256 bits

In which year was DES adopted as a federal standard?

• 1980

• 1975

• 1985

• 1977

What type of cipher is AES classified as?

• symmetric key cipher

• transposition cipher

• hash function

• asymmetric key cipher

What is the primary weakness of DES?

• It uses a single round of encryption, making it fast but insecure.

• DES is not widely used due to its complexity.

• Key length of 128 bits is too long for practical use.

• Short key length of 56 bits makes it vulnerable to brute-force attacks.

Which mode of operation is commonly used with AES?

• Cipher Block Chaining (CBC)

• Counter (CTR)

• Output Feedback (OFB)

• Electronic Codebook (ECB)