Deck 14: Key Management and Distribution

Question 1

For symmetric encryption to work the two parties to an exchange must share the same key and that key must be protected from access by others.

Answer 1

True

Question 2

__________ key encryption schemes are secure if the public key is authenticated.

A)Message
B)Management
C)Public
D)Private

Answer 2

C

Question 3

Although public announcement of public keys is convenient, anyone can forge a public announcement.

Answer 3

True

Question 4

Because certificates are forgeable they cannot be placed in a directory without the need for the directory to make special efforts to protect them.

Question 5

Frequent key changes are usually desirable to limit the amount of data compromised if an attacker learns the key.

Question 6

Some sort of mechanism or protocol is needed to provide for the secure distribution of keys.

Question 7

_________ implementations make use of X.509 certificates.

A)PKI
B)CDC
C)HMAC
D)KDC

Question 8

X.509 defines the format for private-key certificates.

Question 9

X.509 is an important standard because the certificate structure and authentication protocols defined in X.509 are used in a variety of contexts.

Question 10

Master keys can be distributed in some noncryptographic way such as physical delivery.

Question 11

Each user must share a unique key with the key distribution center for purposes of key distribution.

Question 12

The distribution of session keys delays the start of any exchange and places a burden on network capacity.

Question 13

Key distribution often involves the use of _________ which are generated and distributed for temporary use between two parties.

A)public key certificates
B)session keys
C)master keys
D)private key certificates

Question 14

The topics of cryptographic key management and cryptographic key distribution are complex,involving cryptographic,protocol, and management considerations.

Question 15

For link encryption manual delivery is awkward.

Question 16

Key distribution often involves the use of __________ which are infrequently used and are long lasting.

A)private key certificates
B)master keys
C)session keys
D)public key certificates

Question 17

A random number would not be a good choice for a nonce.

Question 18

A public-key certificate scheme alone does not provide the necessary security to authenticate the public key.

Question 19

Typically the session key is used for the duration of a logical connection,such as a frame relay connection or transport connection,and then it is permanently stored.

Question 20

A __________ defines the procedures needed to revoke digital certificates.

A)KDC
B)digital key
C)cryptographic key encryption
D)public key infrastructure

Question 21

A __________ attack is when a protocol is insecure against an adversary who can intercept messages and can either relay the intercepted message or substitute another message.

Question 22

If A and B each has an encrypted connection to a third party C,C can deliver a key on the encrypted links to A and B.A _________ center is responsible for distributing keys to pairs of users as needed.

Question 23

The more frequently session keys are exchanged the more __________ they are because the opponent has less ciphertext to work with for any given session key.

A)insecure
B)streamlined
C)secure
D)obsolete

Question 24

Session keys are transmitted in encrypted form using a __________ key that is shared by the key distribution center and an end system or user.

Question 25

Communication between end systems is encrypted using a _________ key.

A)session
B)master
C)permanent
D)message

Question 26

If encryption is done at the __________ level a key is needed for every pair of users or processes that require communication.

Question 27

Several techniques have been proposed for the distribution of public keys.The proposals can be grouped into the following four general schemes: public announcement,publicly available directory,public-key certificates,and ____________.

Question 28

__________ is an integer value unique within the issuing CA that is unambiguously associated with this certificate.

A)Signature identifier
B)Version
C)Serial number
D)Issuer unique identifier

Question 29

The strength of any cryptographic system rests with the ___________ .

A)end encryption
B)key distribution technique
C)nonce
D)X.509 certificate

Question 30

If __________ is done at a network or IP level a key is needed for each pair of hosts on the network that wish to communicate.

A)end-to-end encryption
B)key management
C)key distribution
D)link encryption

Question 31

The principal objective for developing a _________ is to enable secure,convenient and efficient acquisition of public keys.

A)KDC
B)IETF
C)PKI
D)CRL

Question 32

With the __________ scheme,if an adversary succeeds in obtaining or computing the private key of the directory authority,the adversary could authoritatively pass out counterfeit public keys and subsequently impersonate any participant and eavesdrop on messages sent to any participant.

A)public key authority
B)publicly available directory
C)public key certificates
D)public announcement

Question 33

A unique identifier for a transaction is a __________ and this identifier may be a timestamp,a counter or a random number,with the minimum requirement being that it differs with each request.

Question 34

One of the most important uses of a __________ cryptosystem is to encrypt secret keys for distribution.

A)master key
B)KDC
C)public key
D)end-to-end

Question 35

Public-key encryption schemes are secure only if the authenticity of the ___________ is assured.

Question 36

A _________ is defined as the set of hardware,software,people,policies,and procedures needed to create,manage,store,distribute,and revoke digital certificates based on asymmetric cryptography.

Question 37

Used in a variety of applications,__________ defines the format for public-key certificates.

Question 38

__________ indicates a restriction imposed as to the purposes for which,and the policies under which,the certified public key may be used.

A)Authority key identifier
B)Key usage
C)Subject key identifier
D)Certificate policies

Question 39

__________ is the function that delivers a key to two parties who wish to exchange secure encrypted data.

Question 40

The __________ is the issuer of certificates and certificate revocation lists and may also support a variety of administrative functions.

A)CRL issuer
B)certified user
C)certification authority
D)registration authority

Question 41

__________ is the process whereby a user first makes itself known to a certification authority prior to that certification authority issuing a certificate for that user.

Question 42

__________ certificates are used in most network security applications including IP security,transport layer security and S/MIME.

Question 43

A _________ is a generic term used to denote any method for storing certificates and CRLs so that they can be retrieved by end entities.

Question 44

The directory entry for each certification authority includes two types of certificates: forward certificates and ___________ .

Question 45

A __________ consists of a public key,an identifier of the key owner,and the whole block signed by a trusted third party and can be used by participants to exchange keys without contacting a public key authority in a way that is as reliable as if the keys were obtained directly from a public key authority.