Chapter 6 Flashcards

1
Q

What principle states that a cryptographic system should be secure even if everything about the system, except the key, is public knowledge.

A

Kerckhoff’s Principle/Assumption

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2
Q

What standard defines the hardware and software requirements for cryptographic modules that the federal gov uses?

A

FIPS 140-2

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3
Q

What boolean mathmatics operation has the “^” symbol, where the X and Y values are true only in columns where both X & Y are true.

A

AND

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4
Q

What boolean operation has the “v” symbol and only returns false when both input values are false.

A

OR

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5
Q

What boolean operation has the “~” and reverses the input values for only one variable at a time?

A

NOT

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6
Q

What boolean operation has the “⊕” and returns a true value when only one of the input values is true.

A

XOR

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7
Q

What mathmatical operation easily produces output values for each possible combination of inputs but makes it impossible to retrieve the input values.

A

One-Way Function

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8
Q

What type of cryptosystem are all based on some type of one-way function?

A

Public Key Cryptosystems

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9
Q

What is considered a nonce and is a random number that acts as a placeholder variable in mathematical functions.

A

IV

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10
Q

What describes a cryptographic key being stored with a third party known as a recovery agent and when certain conditions are met, the recovery agent restores an authorized user’s access or decrypt the material themselves.

A

Key Escrow

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11
Q

What type of attack is a Ceasar cipher vulnerable to?

A

Frequency Analysis

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12
Q

What technique protects against direct frequency analysis but is vulnerable to period analysis.

A

Polyalphabetic Substitution

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13
Q

What attack is an examination of frequency based on the repeated use of the key?

A

Period Analysis

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14
Q

What cipher is as long as the message itself and is often chosen from a common book, newspaper, or magazine?

A

Running Key Cipher

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15
Q

What describes the change in the plaintext resulting in multiple changes spread throughout the ciphertext?

A

Diffusion

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16
Q

What type of secret key exist only for a single session and is commonly used by the TLS protocol.

A

Ephemeral Key

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17
Q

What are the major weaknesses with symmetric key cryptography?

A

Key distribution is a major problem
Does not implement non-repudiation
Isn’t scalable
Must be generated often

18
Q

How many symmetric keys do you need for communication between 5 participants?

A

10

19
Q

How many symmetric keys do you need for communication between 3 participants?

A

3

20
Q

How many symmetric keys do you need for communication between 2 participants?

A

1

21
Q

How many symmetric keys do you need for communication between 10 participants?

A

45

22
Q

How many symmetric keys do you need for communication between 100 participants?

A

4,950

23
Q

How many asymmetric keys do you need for communication between 5 participants?

A

10

24
Q

How many asymmetric keys do you need for communication between 10 participants?

A

20

25
Q

How many asymmetric keys do you need for communication between 100 participants?

A

200

26
Q

How many asymmetric keys do you need for communication between 2 participants?

A

4

27
Q

How many asymmetric keys do you need for communication between 4 participants?

A

8

28
Q

How many asymmetric keys do you need for communication between 3 participants?

A

6

29
Q

What cryptographic mode takes the standard CTR mode of encryption and adds data authenticity controls to the mix, providing the recipient assurances of the integrity.

A

Galois/Counter Mode

30
Q

What cryptographic mode combines a confidentiality mode with a data authenticity process?

A

CCM

31
Q

What term describes XORing the plaintext with a separate subkey before the first round of encryption?

A

Prewhitening

32
Q

What are the three main way to securely distribute symmetric keys?

A

Offline Distribution
Public Key Encryption
Diffie-Hellman Key Exchange Algorithm

33
Q

What are the issues with distributing symmetric keys offline?

A

Mail can be Intercepted
Telephones can be wiretapped
Papers with keys can be thrown in the trash or lost

34
Q

What involves the physical exchange of key material?

A

Offline Distribution

35
Q

What involves two parties setting up an initial communications link, authenticating each other’s identity, and exchanging a secret key over the secure public key link.

A

Public Key Encryption

36
Q

What key distribution method is very useful when two parties are unable to physically exchange key material and there is no public key infrastructure.

A

Diffie-Hellman

37
Q

What best practices should you follow with the storage of encryption keys?

A

Never store an encryption key on the same system where encrypted data resides

Give two different individuals half of the key to practice split knowledge

38
Q

What are the two key storing mechanisms you can choose from?

A

Software-Based Storage Mechanisms
Hardware-Based Storage Mechanisms

39
Q

What key storing mechanism store keys as digital objects on the system where they are used?

A

Software-Based Storage Mechanism

40
Q

What key storing mechanism offers added security, more complex and expensive, and are dedicated hardware devices such as HSMs that manage keys for individuals or organizations.

A

Hardware-Based Storage Mechanism

41
Q

What key recovery approach do orgs use when a group of individuals of a certain size who has RA privileges and wish to recover an encryption key, a certain number of them must agree to do so.

A

M of N Control