Cryptography and Network Security

In symmetric-key cryptography, the key locks and unlocks the box is

• 1. Shared

• 1. Same

• 1. Private

• 1. Public

The acronym DES stands for

• 1. Double Encryption Standard

• 1. Digital Evaluation System

• 1. Data Encryption Standard

• 1. Digital Encryption System

Encryption Strength is based on

• 1. Strength of algorithm

• 1. Length of key

• 1. Secrecy of key

• 1. All of the above

In asymmetric key cryptography, the private key is kept by ________

• 1. Sender

• 1. Receiver

• 1. All the connected devices to the network

• 1. Sender and receiver

The ________ is the original message before transformation

• 1. Secret-text

• 1. Plaintext

• 1. Ciphertext

• 1. None of the above

In cryptography, the order of letters in a message is rearranged by ________

• 1. Transpositional ciphers

• 1. Substitution ciphers

• 1. Both (A) and (B)

• 1. Quadratic ciphers

A/an ________ algorithm transforms ciphertext to plaintext

• 1. Encryption

• 1. Decryption

• 1. Both (A) and (B)

• 1. None of the above

In public key encryption, if A wants to send an encrypted message

• 1. A encrypts message using B’s public key

• 1. A encrypts message using his private key

• 1. A encrypts message using B’s private key

• 1. A encrypts message using his public key

The man-in-the-middle attack can endanger the security of the Diffie-Hellman method if two parties are not

• 1. Joined

• 1. Authenticated

• 1. Submit

• 1. Separate

What is data encryption standard (DES)?

• 1. Bit cipher

• 1. Stream cipher

• 1. Block cipher

• 1. Byte cipher