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Domain 3: Cryptography Flashcards

1
Q

What is Plaintext?

A

An unencrypted message

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2
Q

What is Ciphertext?

A

an Encrypted message

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3
Q

What is Cryptology?

A

the science of secure communications

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4
Q

What is Symmetric Encryption?

A

Encryption that uses one key encrypt and decrypt

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5
Q

What is Asymmetric Encryption?

A

Encryption that uses two keys; if you encrypt with one, you may decrypt the other.

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6
Q

What is a Cryptography?

A

creates messages whose meaning is hidden

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7
Q

What is a Cryptanalysis?

A

the science of breaking Encrypted message

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8
Q

It is important to remember that Cryptology encompasses two disciplines. what are they?

A

Cryptography

Cryptanalysis

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9
Q

What is a Cipher?

A

A Cryptographic algorithm

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10
Q

What is a Plaintext?

A

An unencrypted message

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11
Q

What is a Encryption?

A

Converts Plaintext into Ciphertext

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12
Q

Cryptography provides which parts of Confidentiality Integrity Availability (CIA)

A

Confidentiality

Integrity

but not Availability

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13
Q

Cryptography provides which parts of Identity - Authentication - Authorization – Accountability: IAAA)

A

Proving an Identity Claim

Identity - Authentication

but not Availability

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14
Q

can Cryptography provide Non-repudiation?

A

Yes

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15
Q

What is Confusion?

A

The relationship between the Plaintext and the Ciphertext should be as random (Confused) as possible.

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16
Q

What is Permutation?

A

Provides Confusion by rearranging the Plaintext anagram-style

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17
Q

What is Diffusion?

A

The order of the Plaintext should be dispersed (Diffused) in the Ciphertext.

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18
Q

Are Permutation and Substitution are often combined?

A

Yes

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19
Q

What is Substitution?

A

Provides diffusion by replacing one character for another

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20
Q

What should Strong Encryption accomplish?

A

Should destroy patterns.

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21
Q

What metric is used to determine if a cipher uses strong encryption?

A

If a single bit of Plaintext changes, the odds that all of the bits of the resulting Ciphertext should be 50% or greater.

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22
Q

What do Cryptanalysts look for to break an encryption?

A

Any signs of nonrandomness may be used as clues to a Cryptanalyst.

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23
Q

In Cryptanalysis what is the Work Factor?

A

Describes how long it will take to break a cryptosystem.

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24
Q

In Cryptanalysis, what is Breaking a Cryptosystem:

A

Decrypting Ciphertext without a key

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25
Does Secrecy of the cryptographic algorithm provide strength?
No ## Footnote
26
What is a Monoalphabetic Ciphers: ## Footnote
Uses one alphabet for substitution. ## Footnote
27
What is a weakness to Monoalphabetic Ciphers? ## Footnote
Susceptible to Frequency Analysis ## Footnote
28
What is a Polyalphabetic Cipher? ## Footnote
Uses multiple alphabets for substitution. ## Footnote
29
What is Frequency Analysis? ## Footnote
The study of the frequency of letters or groups of letters in a ciphertext. ## Footnote
30
What is Modular Math? ## Footnote
It shows you the remainder
31
What is another name for Modular Math? ## Footnote
Clock Math
32
Why is Modular Math Cryptology? ## Footnote
is is the underlying math behind a lot Cryptography.
33
What does Exclisive OR mean?
A Boolean operator that returns a value of TRUE only if both its operands have different values. an exclusive OR means "this or that, but not both." An exclusive OR is often called an XOR or EOR.
34
What does XOR stand for?
Exclusive Or
35
What is the First known example of secret writing ## Footnote
Egyptian Hieroglyphics
36
What is Egyptian Hieroglyphics? ## Footnote
Stylized pictorial writing used in ancient Egypt.; Some contained small puzzles ## Footnote
37
What is Spartan Scytale?
Used in Ancient Sparta around 400 BC A strip of parchment wrapped around a rod. Plaintext written lengthwise down the rod.When unwound, the parchment was unreadable The receiver possessed a rod of equal length and diameter.
38
What is a Rotation Ciphers ? ## Footnote
Used by Gaius Julius Caesar; rotated each letter of the plaintext three times to encrypt (A became D)
39
What is a another name for a Rotation Ciphers ? ## Footnote
Caesar Cipher
40
What is a Vigenére Ciphers?
A Polyalphabetic rotational Cipher named after Blaise de Vigenére
41
How does a Vigenére Ciphers work?
It consists of the alphabet written out 26 times in different rows, each alphabet shifted cyclically to the left compared to the previous alphabet, corresponding to the 26 possible Caesar ciphers. Top Row holds the plaintext Left Column holds the Ciphertext The person sending the message chooses a keyword and repeats it until it matches the length of the plaintext
42
is the Vigenére Ciphers a Polyalphabetic Cipher or a Monoalphabetic Cipher? ## Footnote
Polyalphabetic Cipher
43
How do you encrypt with a Vigenére Ciphers ?
44
How do you decrypt with a Vigenére Ciphers ?
45
What is a Cipher Disk?
Two concentric disks with an alphabet around the periphery.
46
What is a Monoalphabetic Cipher Disk?
Two parties agree on a fixed offset: Set S to D.
47
What is a Polyalphabetic Cipher Disk?
Same as Monoalphabetic, Two parties agree on a fixed offset: Set S to D. but then the two parties agree to turn the wheel every X characters.
48
What is a a set of Jefferson Disks?
36 Wooden Disks each with 26 letters in random order.
49
How do you encrypt with Jefferson Disks?
Arrange the first 36 letters along one line on the disks ## Footnote Pick any other line and write down the Ciphertext
50
What is a Book cipher? ## Footnote
Uses whole words from a well known text. ## Footnote
51
How do you decrypt with Jefferson Disks?
Arrange the Ciphertext along one line on the disks ## Footnote The recipient looks at all other 25 lines for something that makes sense.
52
How do you encrypt with a Book cipher? ## Footnote
Agree on a text For each word in the plain text, note the Page Number Line Word offset Example from Benedict Arnold to Nathan Bailey As 158.9.25 and 115.9.12 are 226.9.3 As Life and Fortune are risked
53
What is a Running Key Cipher? ## Footnote
Uses a well known text but uses modulus math to add letters to each other
54
How do you encrypt with a Running Key Cipher?
55
What is a Code Book? ## Footnote
Assign a code word for important people, locations and terms. In some cases, assign more than one code word.
56
What is a One Time Pad?
Uses identical paired pads of random characters with a set amount of characters on each page.
57
How do you encrypt with a One Time Pad?
Align the plaintext along the random characters and perform modulo math.
58
What is the only encryption method that is mathematically proven to be secure?
One-Time Pad
59
What are the three prerequisites to ensure that one-time pads are the only encryption method that is mathematically proven to be secure?
1: If the characters are truly random, 2: The pads are kept secure 3: No one page is ever re-used.
60
What is a Vernam Cipher?
A teletypewriter that encrypted and decrypted using paper rolls as the one time pad. The bits were XORd First known use invented by Gilbert Vernam in 1917.
61
Why does Brute Forcing One-Time Pads not work?
Since the key of a one-time-pad is the same length as the Plaintext, brute forcing every possible key will eventually recover the Plaintext, but it will also produce vast quantities of other potential Plaintexts including the works of Shakespear.
62
What is a Hebern Machines ?
The Hebern Rotor Machine was an electro-mechanical encryption machine built by combining the mechanical parts of a standard typewriter with the electrical parts of an electric typewriter, connecting the two through a scrambler. It is the first example (though just barely) of a class of machines known as rotor machines that would became the primary form of encryption during World War II and for some time after, and which included such famous examples as the German Enigma.
63
A Hebern Machine is what kind of encryption machine?
Rotor Machine
64
What is the Enigma machine?
A Rotor Encryption machine that used three finger wheels that could be set to any number from 1-26 used by the Germans in WWII.
65
How do you encrypt with an Enigma machine?
type the plaintext into the typewriter. The wheels will turn and a lamp illuminated with the Ciphertext.
66
How do you decrypt with an Enigma machine?
set the wheels to the original position and type the Ciphertext. The lamp will illuminate the plaintext.
67
What is the SIGBA machine?
Improvement to the Enigma used by the US. Never broken.
68
What is the Purple (Red and Jade) machine?
Rotor-like device used by the Japanese Actually a stepping switch device
69
How did the intelligence community view the technology behind cryptanalysis
Arguably as powerful as any bomb and tried to regulate it through the same munitions laws.
70
Why is the Coordinating Committee for Multilateral Export Controls (COCOM) important?
Designed to control the export of critical technologies to Iron Curtain countries between 1947 and 1994. Export of encryption technologies by members to non-COCOM countries (US, Australia, Turkey, non-soviet union countries in Europe) was heavily restricted.
71
What does COCOM stand for?
The Coordinating Committee for Multilateral Export Controls
72
What is the Wassenaar arrangement?
Created in 1996 after COCOM ended, it included many more countries including former soviet union countries and greatly relaxed the restrictions on exporting cryptography.
73

CISSP (6 decks)

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