Yoo

Front 1

the iso osi refrence model is a theoretics tool for describing connections between systems the most common implementation of a layered architecture for such communication is a suite protocols known by the acronym ___________.

Back 1

tcp/ip

Front 2

an opponent obtains a copy of a legitimate message as it is transmitted over a network link and inserts the copy into the system, so that both the orignal and the copy are delivered.

this is an example of __________.

Back 2

replay attack

Front 3

even if an opponent cannot read the content of messages he may be able to deduce the likley content from observable characteristics. this technique is known as

Back 3

Traffic analysis.

Front 4

analysis showed that double DES does not reduce to a single stage so it is much less vulnerable than single DES to brute force attack . however it is vulnerable to a/an

Back 4

meet in the middle attack.

Front 5

when two different messages generate the same hash value (or the same Mac value for the same key) the result is called a __________

Back 5

collision

Front 6

according to the definition in class,

a threat requires an impending action by a person with hostile intent. true or false?

Back 6

false

Front 7

in typical usage the algorithim used to encrypt a message is known only to the encrypter and the decrypter . true or false

Back 7

false

Front 8

The Boolean exclusive or (xor) operator returns 1(Which is usually interpreted as tr

when both inputs to it are the same true or false ?

Back 8

false.

Front 9

The sender of a message creates a message authentication code (MAC) fo rit using m generation function based on AES encryption. To authenticate the message the recipient must use a MAC verification function on AES decryption .

Back 9

false

Front 10

A threat that does not involve some non -trivial change to a system is known as a _______ threat.

Back 10

passive

Front 11

Selection, design, and implementation of security mechanisms is _______ before an organizationdevelops an information security policy

Back 11

pointless

Front 12

For which of the following moduli are the values 2 and 7 congruent? Inother words:

Back 12

2=7(mod 5)

Front 13

The modular multiplication property shows that (a - Jb) mod n = e

Back 13

[(a mod n) - (b mod n)]mod n nclude_H͟

Front 14

Each cycle of symmetric decryption uses the inverse operations ofthose used in encryption, in the reverse order, with nb

Back 14

the same key as used in encryption mb

Front 15

When using symmetric cryptography, the major challenge for the users isb

Back 15

sharing the key 
b

Front 16

The DES algorithm is an example of a Feistel cipher.
Which of the following statements about the Feistel design is true?

Back 16

The same algorithm is used for both encryption and decryptionnsb

Front 17

In the simplest mode of operation for symmetric block ciphers theplaintext is encrypted with a key and ciphertext is decrypted with the samekey. This is known 1803b

Back 17

as electronic codebook key ab

Front 18

a message authentication code (MAC) sent with a message does not provide the service of non-repudiation because ______

Back 18

they use secret keysmenb

Front 19

Which of the following is the direct outcome of successful use of theprotocol named for Whitfield Diffie and Martin Hellman? (

Back 19

Agreement on a data value,Decryption of a message and Encryption of a message 8C(

Front 20

Which of the following information security services is/areprovided
when a recipient successfully verifies a digital signatureaccompanying a received message? >(

Back 20

non repudiation ,integrity, orgin,

Front 21

The discrete logarithm problem refers to the impracticality of 7(

Back 21

of reversing modular exponentiation for large numbers tabs":(

Front 22

Cipher Block Chaining (CBC) is the mode of operation typically used forgeneral-purpose encryption/decryption. What is the most important distinctionbetween CBC and Electronic Codebook (ECB) mode that makes CBC the appropriatechoice here ?
 tabs":(FH{"back_s+

Back 22

dont know

Front 23

Cipher Block Chaining (CBC) is the mode of operation typically used forgeneral-purpose encryption/decryption. What is the most important distinctionbetween CBC and Electronic Codebook (ECB) mode that makes CBC the appropriatechoice here ?
 tabs":(FH{"back_s+

Back 23

dont know

Front 24

SHA-1 (the revised version of the original Secure Hash Algorithm)generates a 160-bit output value from an input bit sequence that is between 0and 2 -1 bits in length.
Assuming a uniform distribution of output values theprobability of two different messages coincidentally having the same SHA-1 hashvalue is .chԛ

Back 24

dont know

Front 25

RSA encryption may be expressed as C= Me mod n. RSA decryption may beexpressed asmpor(

Back 25

M= C^d mod n

Front 26

a particular binary boolean operator return 0 (or FALSE) if its two inputs are the same, and returns I( or true) if they are different. this operator is known as

Back 26

Xor

Front 27

in some modes of operation for symetric block ciphers a result from one cycle is used in the following cycle. in the first cycle there is no previous value so a special data value must be shared by the encypter and the decrypter ( in addition to the shared key). this special data value is known as___________________.

Back 27

dont know. !!

Front 28

the strength of several asymettric cyrptographic schemes is based on the fact that is easy to calculate expotentials in a modular system, but it is impractical to reverse those calculations for large value. this is known as the __________________________ problem .

Back 28

exchange destrict logrithim.

Front 29

traffic (flow) analysis may allow an opponent to violate the confidentiality of an encrypted message even if he opponent is never able to decrypt the cipher text.

true or false?

Back 29

true

Front 30

by deffinition an asymetric encryption scheme is more then a sysmettric encryption scheme with the same key length and the same amount of computational effort.

Back 30

false

Front 31

the sender of a mesasge creates a message authetication code (MAC) for it using a mac generation fuction based on AES encryption. to authenticate the message the recipeint must use a MAC verfication fuction based on AES decryption.

Back 31

false

Front 32

A threat that if its eventuated would involve a non-trivial change to an information system is known as a/an _______ threat

Back 32

active

Front 33

which of the values shown below is congurent modulo 10 to the value 2? ("modulo 10" means " with respect to the modulus value 10")

Back 33

12, 22

Front 34

the modular property shows that (axb) mod n =

Back 34

[ (a mod n) x (b mod n)] mod n

Front 35

A brute force attack is against double DES was considered infeasible, but a ____ attack was considered feasible

Back 35

meet-in -the middle

Front 36

a good encryption alagortihim will produce cipher text that is apparentley unrelated to the plaintext to anyone who does not know the key. such ciphertext is commonly described as

Back 36

psuedo-random.

Front 37

public key of an enitity is commonly communicated to other entity in a data structure known as

Back 37

certificate

Front 38

which of the following is the direct outcome succesfull use of the protocol named for whitefield diffie and martin heelman?

Back 38

dont know this one

a. agrremtn on a data value

b. assurance that a message is correct

c. decryption of a message

d. deterrence against false claims

e. encryption of a mesage.

Front 39

which of the following information security services is/are provided when a recipeint succesfully verfies a digitial signature accompnaying a received message?

Back 39

non repudiation , authentication of orgin ,

authentication of integrity.

Front 40

electronic codebook mode is used to provide the service of confidentiality but only for every short messages with unpredictable content because.

Back 40

a perticular plaintext block value always produces the same ciphertect block value.

Front 41

rsa encyption may be expressed as c= m^e mod n. rsa decryption may be expressed as

Back 41

m=c^d mod n

Front 42

birefley explain one (1) information security service that is provided by appropriate use of a hash function . be sure to explain why appropriate usage of the hash fuction provides that information security service.

Back 42

auhentication of the intergrety of a hash value directly provides authentication at the person message this will insure that the message has not been altered, by comparing H(m1)=H(M2).

Front 43

user a wants to encrypt a message using a symetric encryption algortithim so that user b can decrypt it when received. user A will generate a " session key " for this encryption .

briefly explain how user will communicate the seesion key to userB over the Network it is not practical to a deliver the key person -to-person.

Back 43

different hellious method can be used user a and b will agree on a psuedacode . random numbers to generate a private key that will be used to calculate a public key. they will share these public keys and get the same k value which b shared as the secret key and caluclate a k value.

Front 44

user a will generate a message and a digital signature for that message and send both to user b. briefley explain which key/s will be used to generate the digital signature. to verify the digital signature , and how each user will obtain the key/s used by that user.

Back 44

answer it

Front 45

user a and user b exchange messages over an information system. user c is an attacker. briefley explain what userc must do to succesfully complete a man- in - the - middle attack. against the communication between user A and user B.

Back 45

answwer it !!