Module 7 - Understanding Cryptography - Q&A Flashcards
Data that is said to be easily readable by humans or machines is called \_\_\_\_\_\_\_\_\_\_. A. ciphertext B. plaintext C. coded text D. encrypted text
B. Data that is said to be easily readable by humans or machines is called plaintext.
Which of the following is the process used to convert ciphertext to plaintext? A. Decryption B. Encryption C. Encoding D. Enciphering
A. Decryption is the process used to convert ciphertext to plaintext.
Which of the following terms describes data that is stored on media, usually in the form of files? A. Data-in-RAM B. Data-in-process C. Data-in-transit D. Data-at-rest
D. Data-at-rest describes data that is stored in the form of files on storage media.
Which of the following terms refers to the output that comes from hashing a piece of text? A. Cipher B. Code C. Message digest D. Key
C. A message digest, or hash, is the resultant output from hashing a piece of text.
How is hashing unlike the encryption and decryption processes?
A. Hashes are not normally reversed or decrypted.
B. Hashes are encoded but not enciphered.
C. Hashes must be decrypted by a key different from the one that was used to encrypt them.
D. Hashes use the same key to encrypt and decrypt.
A. Hashes are not normally reversed or decrypted.
Which of the following terms describes a cryptovariable? A. Key B. Algorithm C. Cipher D. Hash
A. A cryptovariable is also known as a key.
Which of the following components of cryptography are typically publicly known and tested? A. Key B. Algorithm C. Cryptovariable D. Cryptosystem
B. Algorithms are typically publicly known and tested to ensure their dependability.
Which of the following types of algorithms encrypts specified sizes of groups of text at a time? A. Asymmetric B. Symmetric C. Streaming D. Block
D. Block algorithms encrypt entire groups of bits of text, usually of specific sizes.
Which of the following types of keys can decrypt only what another key encrypts? (Choose two.) A. Public key B. Symmetric key C. Private key D. Session key
A, C. Public keys and private keys reside in a key pair, and what one key encrypts, only the other key can decrypt, and vice versa.
You must implement a cryptography system in your organization. You need to be able to send large amounts of data, quickly, over the network. The system will be used by a very small group of users only, and key exchange is not a problem. Which of the following should you consider? A. Asymmetric cryptography B. Symmetric cryptography C. Hybrid cryptography D. Key escrow
B. In this scenario, symmetric key cryptography would probably be the best choice, since the user group is very small and key exchange is not a problem. You also have the requirements of speed and efficiency, as well as the ability to send large amounts of data. All of these are advantages of using symmetric key cryptography.
What are the characteristics of DES?
- Symmetric Algorithm
- 16 rounds of encryption
- 64-bit blocks
- 56-bit keys
- 5 modes of operation
- Well documented weaknesses
- Deprecated
What are the characteristics of 3DES?
- Symmetric Algorithm
- 3 iterations of DES style encryption
- 3 56-bit key bundles
- Some similar weaknesses to DES
- Deprecated
What are the characteristics of AES?
- Symmetric Algorithm
- De-facto standard for U.S. gov. & private/commercial.
- Block cipher
- 128-bit block sizes
- 128/192/256-bit keys
- 10/12/14 rounds of encryption (depending on which key is used)
What are the characteristics of Blowfish?
- Symmetric Algorithm
- 64-bit blocks
- 32 to 448 bit keys
- 16 rounds of encryption
What are the characteristics of Twofish?
- Symmetric Algorithm
- 128-bit blocks
- 128/192/256-bit keys
- 16 rounds of encryption
