Summary Questions
Chapter 7: Elements of Cryptography
7-1.
The output of encryption is _____.
a.
b.
c.
d.
7-2.
Which of the following has to be kept secret in symmetric key encryption?
a.
b.
c.
d.
7-3.
DES
AES
Both of the above.
Neither a. nor b.
Jason sends a message to Kristin using public key encryption for confidentiality.
What key will Jason use to encrypt the message?
a.
b.
c.
d.
7-7.
one
two
four
Which of the following is efficient enough to be used on hand-held devices?
a.
b.
c.
d.
7-6.
confidentiality
authentication
Both of the above.
In symmetric encryption in a two-way dialog, how many keys are used in total for
confidentiality?
a.
b.
c.
7-5.
the encryption method
the encryption key
Both of the above.
Neither a. nor b.
Encryption is used for _____.
a.
b.
c.
7-4.
plaintext
ciphertext
a key
an authenticator
Jason’s private key
Jason’s public key
Kristin’s private key
Kristin’s public key
Jason sends a message to Kristin using public key encryption for confidentiality.
What key will Kristin use to decrypt the message?
a.
b.
c.
d.
726848847
Jason’s private key
Jason’s public key
Kristin’s private key
Kristin’s public key
Page 1 of 2
7-8.
A 256-bit key would be considered to be strong in _____
a.
b.
c.
d.
7-9.
symmetric key encryption
public key encryption
Both of the above
Neither a. nor b.
In MS-CHAP, the shared secret is the _____.
a.
b.
c.
d.
e.
session key
a random bit string
a reusable password
the sender’s private key
the receiver’s public key
7-10. What form of encryption does MS-CHAP use?
a.
b.
c.
d.
symmetric key encryption
public key encryption
Both of the above.
Neither a. nor b.
7-11. Digital signatures are used in _____.
a.
b.
initial authentication
message-by-message authentication
7-12. For digital signatures, the message digest is created by _____.
a.
b.
c.
d.
hashing
public key encryption
symmetric key encryption
Any of the above.
7-13. The digital signature is created by _____.
a.
b.
c.
726848847
hashing
public key encryption
symmetric key encryption
Page 2 of 2