Chp 1 Flashcards

1
Q

What is encryption?

A

Changing plaintext to ciphertext.

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2
Q

What is decryption?

A

The process of changing ciphertext to plaintext.

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3
Q

Mono-alphabetic

A

single mapping from our alphabet to a cipher alphabet.

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4
Q

Polyalphabetic

A

Mapping our alphabet to several cipher alphabets.

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5
Q

One-time Pad

A

Considered ubreakable because it only uses cipher code once.

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6
Q

Psuedo-Random Number Generators (PRNG)

A

Repeats the random numbers after a given time (periodic). Fast and deterministic.

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7
Q

True Random Number Generators

A

Generates a true random number and uses some form of a random process. Non-deterministic and aperiodic.

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8
Q

Frequency Analysis

A

Cipher cracking method that IDs patterns and variations in the probability of codes.

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9
Q

Entropy

A

Measures the level of unpredictability.

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10
Q

ASCII

A

Encoding method that has 8-bit values and up to 256 characters.

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11
Q

UTF-16

A

Encoding method that has 16-bit values and up to 65,536 characters.

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12
Q

Is hardware or software encryption more efficient?

A

Hardware encryption.

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13
Q

Hardware Security Module (HSM)

A

Tamper-evident and intrusion-resistant physical device that safeguards and manages cryptographic keys and provides cryptographic processing.

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14
Q

Trusted Platform Module (TPM)

A

A dedicated processor that handles hardware-level encryption and contains encryption keys. Enables FDE.

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15
Q

Binary Math

A

Knowing what combination of binary digits will produce a binary “1”.

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16
Q

Binary ‘AND’

A

The first and second numbers you are ‘ANDing’ must be 1 for the answer to be 1. Anything else = 0.

17
Q

Binary ‘OR’

A

If either or both numbers are “1”, the answer is “1”.

18
Q

Binary ‘XOR’ (exclusive or)

A

One, but not both, numbers are “1” then the answer is “1”. Anything else is a “0”.

19
Q

Modulus Operator Math

A

Divide the first number by the second and return the remainder. Example: 5 mod 2 = 1

20
Q

Combination vs Permutation

A

combinations = not concerned with the order / permutations = all options considered, including sequence.

21
Q

Probability

A

The likelihood of an event happening.

22
Q

Prime Number

A

Can only be divided by 1 and itself.

23
Q

Pigpen Cipher

A

mono-alphabetic substitution cipher that maps plaintext to graphical characters.

24
Q

Rail Code

A

Scrambles text by writing it in a sequence across several rails.

25
Q

BIFID

A

Uses a grid to map the letters into numeric values.

26
Q

Playfair

A

5 x 5 matrix that contains the alphabet less the letter ‘J’. Has a set of rules using columns and rows.

27
Q

Morse Code

A

Encoding method that translates characters into sequences of dots.

28
Q

Vigenere

A

Polyalphabetic cipher that uses a mapping based on a keyword.

29
Q

Caesar

A

Mono-alphabetic substitution cipher known as a shift cipher. Plaintext is replaced by a letter that is further down.

30
Q

One-Time Pad

A

Cipher code mapping that is used only once.

31
Q

Four-square Cipher

A

Uses four 5 x 5 matrices arranged in a square. Each matrix has 25 letters.

32
Q

Enigma Machine

A

Uses a polyalphabetic substitution cipher and a secret key.