What is the main purpose of encryption?

• To make communication faster

• To conceal the content of a message

• To increase network bandwidth

• To convert data into physical storage

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

• Ciphertext

• Keytext

• Cleartext

• Encrypted message

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

• Encrypting the original text using a key

• Decrypting the encrypted text using a key

• Double encryption using two keys

• Data compression

Which of the following attacks is NOT a type of attack on encryption systems?

• Ciphertext-only attack

• Plaintext insertion attack

• Known plaintext attack

• Chosen plaintext attack

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

• 128 bit

• 64 bit

• 56 bit

• 256 bit

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

• Electronic Codebook (ECB) method

• Cipher Feedback (CFB) method

• Block cipher method

• Triple DES

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

• Public key encryption

• Asymmetric encryption

• Symmetric encryption

• Digital signature

How many keys does Triple DES use to improve security compared to standard DES?

• One

• Two

• Three

• Four

What key length does the IDEA encryption use for its operations?

• 56 bit

• 64 bit

• 128 bit

• 256 bit

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

• RC4

• Triple DES

• Rijndael

• Serpent