Deck 13: Digital Signatures

Question 1

Message authentication protects two parties who exchange
messages from any third party, however, it does not protect the
two parties against each other.

Answer 1

True

Question 2

the main work for signature generation depends on the message
and is done during the idle time of the processor.

Answer 2

False

Question 3

the digital signature function does not include the authentication
function.

Answer 3

False

Question 4

Unlike RSA, DSS cannot be used for encryption or key exchange.

Question 5

__________ is where the attacker forges a signature for a particular message chosen by the attacker.

A)total break
B)Universal forgery
C)Existential forgery
D)Selective forgery

Question 6

It is important in a direct digital signature to perform an outer
confidentiality function first and then the signature function.

Question 7

It must be computationally infeasible to forge a digital signature,
either by constructing a new message for an existing digital
signature or by constructing a fraudulent digital signature for a given message.

Question 8

Similar to the generic attack, except that the list of messages to be signed is chosen after the attacker knows the user's public key but before any signatures are seen, is the __________ attack.

A)directed chosen
B)key-only
C)adaptive chosen
D)known message

Question 9

the first part of the Schnorr digital signature scheme is the
generation of a private/public key pair.

Question 10

the global public key components of DSA are the same as for the
Schnorr signature scheme.

Question 11

A digital signature can guarantee the integrity but not the source of
the message.

Question 12

the __________ is formed by taking the hash of the message and encrypting the message with the creator's private key.

A)timestamp
B)message digest
C)hash code
D)digital signature

Question 13

the most important development from the work on public-key
cryptography is the digital signature.

Question 14

the Schnorr signature scheme is based on discrete logarithms.

Question 15

It must be relatively difficult to recognize and verify the digital
signature.

Question 16

With a __________ attack the attacker is given access to a set of messages and their signatures.

A)known message
B)key-only
C)directed chosen message
D)generic chosen message

Question 17

the global public key components for DSA are p, q, and h.

Question 18

the digital signature standard is a __________ standard that uses the secure hash algorithm.

A)IEEE
B)NISt
C)ISO
D)ItIL

Question 19

the ElGamal signature scheme involves the use of the public key
for encryption and the private key for decryption.

Question 20

the DSS approach makes use of a hash function.

Question 21

the term __________ refers to a digital signature scheme that involves only the communicating parties.

Question 22

A _________ is an authentication mechanism that enables the creator of a message to attach a code that acts as a signature.

Question 23

With a __________ attack the attacker is allowed to use the user as an "oracle".this means that the user may request signatures of messages that depend on previously obtained message-signature pairs.

A)adaptive chosen message
B)generic chosen
C)directed chosen message
D)known message

Question 24

to create a __________ a user calculates two quantities, r and s, that are functions of the public key components (p, q, g), the user's private key (x), the hash code of the message H(M), and an additional integer k that should be generated randomly or pseudorandomly and be unique for each signing.

A)signature
B)hash authentication
C)secret key
D)global key

Question 25

As with ElGamal encryption, the global elements of __________ are a prime number q and a, which is a primitive root of q.

A)ElGamal digital signature
B)digital signature standard
C)digital signature
D)direct digital signature

Question 26

the ____________ components of DSA are the same as in the Schnorr signature scheme.

A)private key
B)EDS
C)global public key
D)message digest

Question 27

the first stage in generating an RSA-PSS signature of a message
M is to generate from M a fixed-length message digest, called an ______________.

Question 28

A __________ is where the attacker determines the user's private key.

A)universal forgery
B)selective forgery
C)existential forgery
D)total break

Question 29

In the digital signature algorithm the user's __________ is represented by x, which is a random or pseudorandom integer with 0 < x < q.

A)per message secret number
B)private key
C)global key
D)public key

Question 30

A digital signature must have the following properties: it must verify the author and the date and time of the signature; it must authenticate the contents at the time of the signature; and it must ___________ to resolve disputes.

Question 31

the __________ encryption scheme is designed to enable encryption by a user's public key with decryption by the user's private key.

Question 32

the _________________, which is the latest of the RSA schemes, is the one that RSA Laboratories recommends as the most secure of the RSA schemes.

A)RSA-PSS
B)ECDSA
C)DSA-SDS
D)EDSDS

Question 33

In the __________ approach only the sender knows the private key so only the sender could have produced a valid signature.

A)EDS
B)DSA
C)DSS
D)RSA

Question 34

the attacker finds an efficient signing algorithm that provides an equivalent way of constructing signatures on arbitrary messages is a ___________ .

Question 35

the __________ attack is where the attacker chooses a list of messages before attempting to break the user's signature scheme, independent of the user's public key.the attacker then obtains from the user valid signatures for the chosen messages.

Question 36

the DSS makes use of the Secure Hash Algorithm and presents a new digital signature technique known as the ______________ .

Question 37

_________ specifies that if the signature generation process results in a value of s = 0 a new value of k should be generated and the signature should be recalculated.

Question 38

the digital signature approach uses an algorithm that is designed to provide only the _________ function.

A)digital signature
B)ElGamal
C)DSA
D)timestamp

Question 39

the __________ scheme minimizes the message dependent amount of computation required to generate a signature.

Question 40

the __________ scheme minimizes the message dependent amount of computation required to generate a signature.

A)Rabin
B)SHA-1
C)ElGamal
D)Schnorr

Question 41

the _________ is based on the difficulty of computing discrete logarithms and is based on schemes originally presented by ElGamal and Schnorr.

Question 42

Administrative controls relating to the security of private keys can be employed by including a ____________ (which includes date and time) and to require prompt reporting of compromised keys to a central authority.

Question 43

the message dependent part of the Schnorr digital signature generation requires multiplying a __________ with an n-bit integer.

Question 44

FIPS 186 -3 incorporates digital signature algorithms based on RSA and on __________ cryptography.

Question 45

In addition to the NISt Digital Signature Algorithm and ECDSA, the 2009 version of FIPS 186 also includes several techniques based on _________ , all of which were developed by RSA Laboratories and are in wide use.