Deck 10: Other Public-Key Cryptosystems

Question 1

the key exchange protocol is vulnerable to a __________ attack because it does not authenticate the participants.

A)one-way function
B)time complexity
C)chosen ciphertext
D)man-in-the-middle

Answer 1

D

Question 2

the __________ cryptosystem is used in some form in a number of standards including DSS and S/MIME.

A)Rabin
B)Rijnedel
C)Hillman
D)ElGamal

Answer 2

D

Question 3

For determining the security of various elliptic curve
ciphers it is of some interest to know the number of
points in a finite abelian group defined over an elliptic
curve.

Answer 3

True

Question 4

the Diffie-Hellman key exchange is a simple public-key
algorithm.

Question 5

the security of ElGamal is based on the difficulty of
computing discrete logarithms.

Question 6

A considerably larger key size can be used for ECC
compared to RS
A.

Question 7

ECC is fundamentally easier to explain than either RSA or
Diffie-Hellman.

Question 8

For purposes of ECC, elliptic curve arithmetic involves
the use of an elliptic curve equation defined over an
infinite field.

Question 9

the ____________ protocol enables two users to establish a secret key using a public-key scheme based on discrete logarithms.

A)Micali-Schnorr
B)Elgamal-Fraiser
C)Diffie-Hellman
D)Miller-Rabin

Question 10

there is not a computational advantage to using ECC
with a shorter key length than a comparably secure tS
A.

Question 11

Most of the products and standards that use public-key
cryptography for encryption and digital signatures use RS
A.

Question 12

the Diffie-Hellman algorithm depends on the difficulty of
computing discrete logarithms for its effectiveness.

Question 13

An encryption/decryption system requires that point
P_m be encrypted as a plaintext.

Question 14

A number of public-key ciphers are based on the use of
an abelian group.

Question 15

the security of ECC depends on how difficult it is to
determine k given kP and P.

Question 16

A(n) __________ is defined by an equation in two variables with coefficients.

A)abelian group
B)binary curve
C)cubic equation
D)elliptic curve

Question 17

Elliptic curves are ellipses.

Question 18

__________ can be used to develop a variety of elliptic curve cryptography schemes.

A)Elliptic curve arithmetic
B)Binary curve
C)Prime curve
D)Cubic equation

Question 19

Since a symmetric block cipher produces an apparently
random output it can serve as the basis of a
pseudorandom number generator.

Question 20

the form of cubic equation appropriate for
cryptographic applications for elliptic curves is
somewhat different for GF(2^m) than for Z_p.

Question 21

Elliptic curve arithmetic can be used to develop a variety of elliptic curve cryptography schemes, including key exchange, encryption, and ___________ .

Question 22

For a ___________ defined over GF(2m), the variables and coefficients all take on values in GF(2m) and in calculations are performed over GF(2m).

A)cubic equation
B)prime curve
C)binary curve
D)abelian group

Question 23

the purpose of the ___________ algorithm is to enable two users to securely exchange a key that can then be used for subsequent encryption of messages.

Question 24

If a secret key is to be used as a _________ for conventional encryption a single number must be generated.

A)discrete logarithm
B)prime curve
C)session key
D)primitive root

Question 25

Included in the definition of an elliptic curve is a single element denoted O and called the point at infinity or the __________ .

A)prime point
B)zero point
C)abelian point
D)elliptic point

Question 26

the Diffie-Hellman key exchange formula for calculation of a secret key by User A is:

A)K = nB x PA
B)K = nA x PB
C)K = nP x BA
D)K = nA x PA

Question 27

A __________ GF(2m) consists of 2m elements together with addition and multiplication operations that can be defined over polynomials.

Question 28

the principal attraction of __________, compared to RSA, is that it appears to offer equal security for a far smaller key size, thereby reducing processing overhead.

Question 29

the key exchange protocol vulnerability can be overcome with the use of digital signatures and __________ certificates.

Question 30

two families of elliptic curves are used in cryptographic applications: prime curves over Zp and __________ over GF(2m).

Question 31

We use a cubic equation in which the variables and coefficients all take on values in the set of integers from 0 through p - 1 and in which calculations are performed modulo p for a __________ over Zp.

Question 32

For cryptography the variables and coefficients are restricted to elements in a __________ field.

A)primitive
B)infinite
C)public
D)finite

Question 33

the __________ key exchange involves multiplying pairs of nonzero integers modulo a prime number q.Keys are generated by exponentiation over the group with exponentiation defined as repeated multiplication.

A)Diffie-Hellman
B)Rabin-Miller
C)Micali-Schnorr
D)ElGamal

Question 34

A(n) ___________ G is a set of elements with a binary operation, denoted by *, that associates to each ordered pair (a,b) of elements in G an element ( a*b) in G.

Question 35

If three points on an elliptic curve lie on a straight line their sum is __________ .

A)0
B)1
C)6
D)3

Question 36

to form a cryptographic system using __________ we need to
find a "hard-problem" corresponding to factoring the product of two primes or taking the discrete logarithm.

Question 37

____________ makes use of elliptic curves in which the variables and coefficients are all restricted to elements of a finite field.

A)Prime curve
B)Elliptic curve cryptography (ECC)
C)abelian group
D)Micali-Schnorr

Question 38

the addition operation in elliptic curve cryptography is the counterpart of modular multiplication in RSA, and multiple addition is the counterpart of __________ .

Question 39

An encryption/decryption system requires a point G and an elliptic group _________ as parameters.

A)Eb(a,q)
B)Ea(q,b)
C)En(a,b)
D)Eq(a,b)

Question 40

__________ are best for software applications.

A)Binary curves
B)Prime curves
C)Bit operations
D)Abelian groups

Question 41

Eq(a,b) is an elliptic curve with parameters a, b, and q, where
_________ is a prime or an integer of the form 2^m.

Question 42

Asymmetric algorithms are typically much slower than
symmetric algorithms so they are not used to generate open-ended __________ generator bit streams.

Question 43

the __________ pseudorandom number generator is
recommended in the ANSI standard X9.82 (Random Number Generation) and in the ISO standard 18031 (Random Bit Generation).

Question 44

A __________ of a prime number p is one whose powers
modulo p generate all the integers from 1 to p-1.

Question 45

the fastest known technique for taking the elliptic curve
logarithm is known as the _________ method.