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Flashcards in Cryptography Deck (258)
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1

What does CIA mean in relation to Cryptography?

Confidentiality, Integrity and Authentication

2

What is non-repudiation?

An action that cannot be denied

3

Non-repudiation can be used to provide what 3 things?

Identification, Authentication and Accountability

4

What is a mono-alphabetic substitution?

A system that uses only a single alphabet to encrypt and decrypt a message

5

What is a practitioner of cryptography known as?

Cryptographer

6

What term is used to describe the science of deciphering cipher text without the cryptographic key?

Cryptanalysis

7

What is Cryptology?

The science of cryptography and cryptanalysis

8

What is a practitioner of Cryptology called?

Cryptologist

9

What is a plaintext message?

A message in its original readable format

10

What is a ciphertext message?

A plaintext message that's been encrypted

11

What other term can be used to describe decryption?

Deciphering

12

What are two methods of encrypting traffic on a network?

End-to-End encryption
Link encryption

13

What type of encryption is used where a packets are encrypted at the original source and then decrypted once they reach the final destination?

End-to-End encryption

14

What are the two advantages of end-to-end encryption?

Speed
Overall security

15

What is the downside to end-to-end encryption?

Only data in encrypted, not routing information

16

What is Link encryption?

requires that each node (ie router) has separate key pairs for its upstream and downstream neighbours. Packets are encrypted and decrypted at each node along the network path

17

What is the advantage of link encryption?

Entire packet including routing information is encrypted

18

What are the two disadvantages of link encryption?

- Latency
- Inherent vulnerability: If a node is compromised or a packets decrypted contents are cached on the router then the data can be compromised

19

What is the hardware or software implementation that transfers plaintext into ciphertext known as?

A cryptosystem

20

What 3 properties must an effective cryptosystem have?

- efficient method of encrypting and decrypting keys on the system
- cryptosystem is easy to use
- strength of the cryptosystem depends on the secrecy of the keys

21

What is a keyspace in relation to a cryptosystem?

A range of all possible values for a key within a cryptosystem

22

What is a keyspace in relation to a cryptosystem?

A range of all possible values for a key within a cryptosystem

23

What is a restricted algorithm?

refers to an algorithm that must be kept secret in order to provide security.

24

What is the disadvantage of a restricted algorithm?

relies on secrecy of the keys rather than complexity of the algorithm used

25

What are the two basic elements of a cryptosystem?

- Cryptographic algorithm
- Cryptovariable

26

What is another term for a cryptographic algorithm?

Cipher

27

What is another term for a cryptovariable?

Key

28

What is key clustering?

Clustering occurs when identical ciphertetx messages are generated form a plaintext message by using the same encryption algorithm but different encryption keys

29

What is a weakness of key clustering?

reduces the number of key combinations that must be attempted in a brute force attack due to a weakness in the cryptographic algorithm

30

What are the two main classes of ciphers used in symmetric key algorithms?

block and stream