Quiz về Mã hóa

What is the primary purpose of encryption?

• To make communication faster

• To hide the substance of a message

• To enhance network bandwidth

• To convert data into physical storage

Which term refers to a message in human-readable form before it is encrypted?

• Ciphertext

• Keytext

• Cleartext

• Encrypted message

What does the function D(K, C) represent in cryptography?

• Encryption of plaintext using a key

• Decryption of ciphertext using a key

• Double encryption using two keys

• Data compression

Which of the following is NOT a type of attack on a cryptosystem?

• Ciphertext-only attack

• Plaintext-injection attack

• Known-plaintext attack

• Chosen-plaintext attack

What is the key size used in the Data Encryption Standard (DES)?

• 128 bits

• 64 bits

• 56 bits

• 256 bits

Which of the following encryption modes treats the plaintext as a continuous stream of data?

• Electronic codebook mode

• Cipher feedback (CFB) mode

• Block cipher mode

• Triple DES mode

Which cryptographic technique involves using the same key for both encryption and decryption?

• Public-key encryption

• Asymmetric encryption

• Symmetric encryption

• Digital signatures

Triple DES uses how many keys to improve security over standard DES?

• One

• Two

• Three

• Four

IDEA encryption uses which key length for its operations?

• 56 bits

• 64 bits

• 128 bits

• 256 bits

Which of the following was selected as the proposed Advanced Encryption Standard (AES) by NIST?

• RC4

• Triple DES

• Rijndael

• Serpent