Security - Roger - Chapter 7 Exam Questions With All Correct Detailed Answers 2025 New Update

Security - Roger - Chapter 7 Exam Questions With All Correct Detailed Answers 2025 New Update What is a cipher that does not replace letters but simply rearranges them? - Answer - Transposition Cipher What cipher substitutes one letter for an other? - Answer - Substitution Cipher What is the term for the practice and study of determining the meaning of encrypted information? - Answer - Cryptanalysis What method is used by attackers that tries every possible key knowing that eventually one of them will work? - Answer - Brute-Force What method is used by attackers when they have access to the ciphertext and of several messages and knows nothing about the plaintext? - Answer - Ciphertext What method is used by attackers when they have access to the ciphertext and of several messages and knows something about the plaintext? - Answer - Known-Plaintext What method is used by attackers who chooses which data the encryption device encrypts and observes the cipher out put? - Answer - Chosen-Plaintext What method is used by attackers who chooses different ciphertext to be decrypted and has access to the decrypted data? - Answer - Chosen-Ciphertext What method is used by attacker who knows a portion of the plaintext and the corresponding ciphertext? - Answer - Meet-in-the-Middle What is the term for the development and use of codes? - Answer - Cryptography A customer purchases an item from an e-commerce site. The e-commerce site must maintain proof that the data exchange took place between the site and the customer. Which feature of digital signatures is required? - Answer - non-repudiation of the transaction Which requirement of secure communications is ensured by the implementation of MD5 or SHA hash generating algorithms? - Answer - integrity The following message was encrypted using a Caesar cipher with a key of 2: fghgpf vjg ecuvng What is the plaintext message? - Answer - defend the castle What is the service framework that is needed to support large-scale public key-based technologies? - Answer - PKI What is a difference between symmetric and asymmetric encryption algorithms? - Answer - Symmetric encryption algorithms use pre-shared keys. Asymmetric encryption algorithms use different keys to encrypt and decrypt data What is the reason for HMAC to use an additional secret key as input to the hash function? - Answer - to provide authentication Which type of attack does the use of HMACs protect against? - Answer - MITM A network administrator is forced to use DES on aging equipment. What is one thing the administrator should do in this situation? - Answer - Implement CBC mode. The SHA-224, SHA-256, SHA-384, and SHA-512 hash functions are known collectively as ____________ algorithms. - Answer - SHA-2 If an asymmetric algorithm uses a public key to encrypt data, what is used to decrypt it? - Answer - private key What is the purpose of the DH algorithm? - Answer - to generate a shared secret between two hosts that have not communicated before Which encryption algorithm is an asymmetric algorithm? - Answer - DH Which statement describes asymmetric encryption algorithms? - Answer - They are relatively slow because they are based on difficult computational algorithms. Why is asymmetric algorithm key management simpler than symmetric algorithm key management? - Answer - One of the keys can be made public. What is the most common use of the Diffie-Helman algorithm in communications security? - Answer - to secure the exchange of keys used to encrypt data