Chapter 1

Question 1

What is encryption?

Answer 1

changing plaintext to ciphertext

Question 2

What is decryption?

Answer 2

changing ciphertext back into plaintext

Question 3

Encryption should be applied to information you want to protect _______ and ________.

Answer 3

at rest/in transit

Question 4

Aescrypt is used to encrypt __________.

Answer 4

individual files

Question 5

Bitlocker or FileVault are used to encrypt ____________.

Answer 5

full disks

Question 6

Monoalphabetic

Answer 6

is where a single mapping from our alphabet to a cipher alphabet is created. Many early cryptosystems used this.

Question 7

Polyalphabetic

Answer 7

refers to the mapping of our alphabet to a number of cipher alphabets. This approach added a bit more complexity to early cryptosystems.

Question 8

One-Time Pad

Answer 8

considered to be unbreakable since it only uses its cipher once.

Question 9

Pseudo-Random Number Generators (PRNGs)

Answer 9

This method repeats the random numbers after a given time (periodic). They are fast and also deterministic and are useful in producing a repeatable set of random numbers.

Question 10

True Random Number Generators (TRNGs)

Answer 10

This method generates a true random number and uses some form of random process. One approach is to monitor the movements of a mouse pointer on a screen or form the pauses between keystrokes. Overall, this method is generally slow, especially if it involves human interaction. but it is non-deterministic and aperiodic.

Question 11

Frequency Analysis

Answer 11

is a cipher cracking methodology that involves identifying patterns and variations in the probability of codes (i.e. a three-letter ciphered text combination spotted at the beginning of a string too often could tip us off that those three letters correlate the letters THE in the English alphabet).

Question 12

Entropy

Answer 12

measures level of unpredictability; in encryption relates to the degree of uncertainty of the encryption process.

Question 13

ASCII

Answer 13

Common binary to characters encoding method. 8-bit values, up to 256 characters.

Question 14

UTF-16

Answer 14

Common binary to characters encoding method. 16-bit values, up to 65,536 characters.

Question 15

Hardware versus Software encryption

Answer 15

Hardware encryption is more efficient than software encryption.

Question 16

Hardware Security Module (HSM)

Answer 16

is a tamper-evident and intrusive-resistant physical device that safeguards and manages cryptographic keys and provides cryptographic processing.