quiz 12 Flashcards
Cryptography is the practice of hiding information.
True—The general definition for cryptography is the practice of hiding information.
Encryption is a type of cipher
False—Encryption is the process of changing information using a cipher or algorithm.
A key is an essential piece of information that determines the output of a cipher
True—The key is indispensable, without it there would be no result to the cipher computation.
Public keys are known only to specific users who keep the key secret.
False—Public keys are known to all parties involved in the encrypted transaction. Private keys are known only to a specific user or users who keep their keys secret.
Symmetric key algorithms are a type of cipher that uses identical or closely related keys.
True—The symmetric key algorithm is a class of cipher that uses identical or closely related keys for encryption and decryption.
. A stream cipher is a type of algorithm that encrypts a group of bits collectively as blocks.
False—A stream cipher is a type of algorithm that encrypts each byte in a message one at a time. Block ciphers encrypt a group of bits collectively as blocks.
Symmetric key algorithms require a secure initial exchange of one or more secret keys
True—Symmetric key algorithms need to secure initial exchange of one or more secret keys between the sender and the receiver to work effectively
Public key cryptography uses asymmetric keys alone or in addition to symmetric keys.
True—Public key cryptography doesn’t need to secure exchange of secret keys and generally uses asymmetric keys.
Steganography uses a certificate authority to manage keys
False—Steganography is the science of writing hidden messages; it is a form of security through obscurity and does not deal with keys or certificate authorities.
DES is a commonly used block cipher.
False—DES is an older type of block cipher considered deprecated and has been replaced by other standards such as AES.
Which of the following is a common standard used today and relies on a 256-bit block size? A. AES B. DES C. Triple DES D. RC4
A. AES, the advanced encryption standard is a commonly used encryption type that can work with 128-, 192-, 256-bit block sizes.
Which of the following is a stream cipher? A. DES B. RC 4 C. AES D. RC 6
B. RC4 uses a stream cipher and is known for speed and simplicity. The rest of the answers use block ciphers.
Which of the following are asymmetric encryption algorithms? (Select the two best answers.) A. RSA B. RC6 C. Diffie-Hellman D. AES
A and C. RSA and Diffie-Hellman are asymmetric encryption algorithms. RC6 and AES are symmetric encryption algorithms.
Which of the following encryption algorithms is based on the structure of an elliptic curve? A. RSA B. ECC C. RC4 D. One-time pad
B. Elliptic curve cryptography (ECC) is a type of public key cryptography based on the structure of an elliptic curve.
Which of the following types of encryption can encrypt plaintext with a secret random key that is the same length as the plaintext? A. PGP B. ECC C. One-time pad D. RSA
C. A one-time pad can be computed by hand with pencil and paper; it encrypts plaintext with a secret random key that is the same size as the plaintext to be encrypted
