Cryptographic hard

What is the primary purpose of cryptography in information security?

• To ensure data integrity

• To prevent unauthorized access

• To ensure non-repudiation

• To store data in a secure way

Answer explanation

Cryptography ensures data integrity, prevents unauthorized access, and ensures non-repudiation.

What are some limitations of using cryptography for securing data?

• Cryptography can prevent access to data in a cyberattack

• Cryptography can prevent data from being intercepted during transmission.

• Cryptography can make data unreadable to unauthorized users but cannot prevent data loss or destruction.

• All of above

Answer explanation

While cryptography can make data unreadable to unauthorized users, it cannot prevent data loss or destruction.

What is the difference between symmetric and asymmetric encryption?

• Symmetric uses the same key for encryption and decryption, while asymmetric uses different keys.

• Symmetric uses different keys for encryption and decryption, while asymmetric uses the same key.

• Symmetric is less secure than asymmetric.

• Asymmetric is less secure than symmetric.

Answer explanation

Symmetric encryption uses the same key for both encryption and decryption, while asymmetric encryption uses different keys (public key for encryption and private key for decryption).

What is a cryptographic hash function?

• • A function that ensures data integrity

  
  

• A function that converts plaintext into ciphertext

• A function that ensures non-repudiation

• A function that converts an input (or ‘message’) into a fixed-size string of bytes

Answer explanation

A cryptographic hash function is a special class of hash functions which has various kinds of security applications in information security.

What is the main use of a digital signature?

• It verifies the authenticity of digital messages or documents.

• It encrypts messages or documents.

• It decrypts messages or documents.

• It hashes messages or documents.

Answer explanation

A digital signature is a mathematical scheme for verifying the authenticity of digital messages or documents.

What is the role of a certificate authority in a Public Key Infrastructure (PKI)?

• It issues digital certificates.

• It manages keys and certificates.

• It provides a directory service.

• All of the above

Answer explanation

In cryptography, a certificate authority or certification authority (CA) is an entity that issues digital certificates and manages keys and certificates.

What is the difference between block ciphers and stream ciphers?

• Block ciphers encrypt data in blocks, while stream ciphers encrypt data one bit at a time.

• Stream ciphers encrypt data in blocks, while block ciphers encrypt data one bit at a time.

• Block ciphers are more secure than stream ciphers.

• All of above

Answer explanation

Block ciphers encrypt data in blocks, while stream ciphers encrypt data one bit at a time.

How does the Advanced Encryption Standard (AES) work and what are its key sizes?

• AES is a symmetric encryption algorithm with key sizes of 128, 192, and 256 bits.

• AES is an asymmetric encryption algorithm with key sizes of 1024, 2048, and 3072 bits.

• AES is a symmetric encryption algorithm with key sizes of 1024, 2048, and 3072 bits.

• AES is an asymmetric encryption algorithm with key sizes of 128, 192, and 256 bits.

Answer explanation

AES is a symmetric encryption algorithm with key sizes of 128, 192, and 256 bits

What is the purpose of a key exchange in cryptography?

• To generate cryptographic keys.

• To securely share cryptographic keys over a public network.

• To store cryptographic keys.

• All of above

Answer explanation

The purpose of a key exchange in cryptography is to securely share cryptographic keys over a public network.

How does RSA encryption work?

• RSA uses a block cipher to encrypt data.

• RSA uses a stream cipher to encrypt data.

• RSA uses two mathematically linked keys: one for encryption and the other for decryption.

• RSA uses the same key for both encryption and decryption.

Answer explanation