Ch2 Cryptography

Question 1

how does an Exclusive OR algorithm work?

Answer 1

a key is applied at the bit level, and if the values are different (true-false or false-true) the output is true, otherwise false

Question 2

what is Kerckhoff’s principle?

Answer 2

you can determine the algorithm of an encryption, but without the key you will still not be able to decrypt it

Question 3

what are the 3 locations data can be encrypted?

Answer 3

storage media (data in place); data in transit (while being sent); data in process (in active memory)

Question 4

why is binary XOR encryption sometimes not sufficient obfuscation?

Answer 4

patterns will still emerge in the encrypted data

Question 5

in symmetric encryption the key can be shared _______ (with the message) or ________ separately

Answer 5

in band; out of band

Question 6

symmetric encryption can be very secure if the key is _____

Answer 6

ephemeral (temporary)

Question 7

sometimes ______ encryption is used to send the key for symmetric encryption

Answer 7

asymmetric

Question 8

the _____ encryption algorithm was developed by IBM

Answer 8

Data Encryption Standard (DES)

Question 9

the __________ was developed through an encryption conference in the 90’s, and has been adopted by the US government

Answer 9

Advanced Encryption Standard (AES)

Question 10

in ___________, rather than encrypting chunks, pseudo=random bits are encrypted one at a time

Answer 10

streaming ciphers

Question 11

in ___ encryption prime numbers are multiplied in order to create key pairs

Answer 11

RSA

Question 12

in a _______ exchange, the parties to a communication add their private key to a public key using modular arithmetic

Answer 12

Diffie-Hellman

Question 13

in ____ encryption, a random key is used to encrypt the data, then that key is encrypted using a public key

Answer 13

PGP

Question 14

the purpose of Hashing is..

Answer 14

to verify the integrity of data

Question 15

when the Hashes of two different data sources turns out to be the same, this is called a:

Answer 15

collision

Question 16

Hash algorithm developed by NIS

Answer 16

Secure Hash Algorithm (SHA)

Question 17

________ is hiding one set of data inside another

Answer 17

Steganography

Question 18

________ is a hash of a public key, encrypted private key, and a webpage

Answer 18

digital signature

Question 19

a guarantee of authenticity of a site by a 3rd party, along with their digital signature, is a ________

Answer 19

digital certificate

Question 20

when websites simply begin certifying each other’s authenticity, this is called _______

Answer 20

web of trust

Question 21

when websites are certified by a Certificate Authority (CA) through a hierarchy of intermediaries, this is called ___________

Answer 21

public key infrastructure (PKI)

Question 22

the list of intermediaries a website goes through to achieve certification in a PKI system is called ______

Answer 22

certification path

Question 23

the _____ format is used for organizing and querying data

Answer 23

x.509

Question 24

the _____ standard is used for exporting certificates, while the _____ standard is used for exporting packages including certificates and private keys

Answer 24

PKCS-7; PKCS-12

Question 25

a ____ is a URL that allows verification of a certificate as of 24 hours ago, but ______ is more real-time

Answer 25

certificate revocation lists (CRL); online certificate status protocol (OCSP)

Question 26

passwords are generally stored as _____

Answer 26

hashes

Question 27

in a ______ attack several attempts are made to match a password

Answer 27

brute force

Question 28

two methods to add complexity or length to passwords are ___ and ____

Answer 28

salt; key stretching

Question 29

in a _____ attack, common words with variations are compared against the password

Answer 29

dictionary

Question 30

in a _____ attack, huge indexes of hash tables are used for comparison to a password

Answer 30

rainbow table

Question 31

in symmetric block encryption, ECB refers to _______ which is imperfect because____

Answer 31

electronic code book; it uses consistent key and block sizes, making it vulnerable to pattern recognition

Question 32

in symmetric block encryption, CBC refers to ____

Answer 32

cipher block chaining

Question 33

in symmetric block encryption, CFB refers to ____

Answer 33

cipher feedback

Question 34

in symmetric block encryption, OFB refers to ____

Answer 34

output feedback

Question 35

in symmetric block encryption, CTR refers to ____

Answer 35

counter