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1. Symmetric algorithms support confidentiality, but not authentication and nonrepudiation.
a.
True
b.
False
ANSWER:
True
2. AES uses a 128-bit key and is used in PGP encryption software.
a.
True
b.
False
ANSWER:
False
3. Symmetric algorithms use two keys that are mathematically related.
a.
True
b.
False
ANSWER:
False
4. Asymmetric algorithms are more scalable than symmetric algorithms.
a.
True
b.
False
ANSWER:
True
5. ECC is an efficient algorithm requiring few hardware resources, so it’s a perfect candidate for wireless
devices and cell phones.
a.
True
b.
False
ANSWER:
True
6. Cryptography is the process of converting plaintext, which is readable text, into unreadable or encrypted text
called which if the following?
a.
ciphertext
b.
cleartext
c.
maskedtext
d.
subtext
ANSWER:
a
7. Which of the following is the process of converting ciphertext back into plaintext?
a.
ciphering
b.
encryption
c.
decryption
d.
decoding
ANSWER:
c
8. What type of cryptography is demonstrated by reversing the alphabet so A becomes Z, B becomes Y, and so
on?
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a.
complete cipher
b.
substitution cipher
c.
alphabet cipher
d.
roman cipher
ANSWER:
b
9. If a security expert decides to study the process of breaking encryption algorithms, they are performing which
of the following?
a.
cryptography
b.
ciphering
c.
cryptanalysis
d.
substitution analysis
ANSWER:
c
10. Which of the following is a mathematical function or program that works with a key?
a.
encryption algorithm
b.
key
c.
generated algorithm
d.
key algorithm
ANSWER:
a
11. Which of the following is a range of allowable values that is used to generate an encryption key?
a.
algorithm area
b.
key range
c.
keyspace
d.
keyarea
ANSWER:
c
12. What type of system converts between plaintext and ciphertext?
a.
opensystem
b.
cryptokey
c.
keyedsystem
d.
cryptosystem
ANSWER:
d
13. Which of the following refers to verifying the sender or receiver (or both) is who they claim to be?
a.
Authentication
b.
Nonrepudiation
c.
Availability
d.
Authorization
ANSWER:
a
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14. Which function ensures that a sender and receiver cannot deny sending or receiving a specific message?
a.
Authentication
b.
Nonrepudiation
c.
Availability
d.
Integrity
ANSWER:
b
15. Cryptosystems that have a single key that encrypts and decrypts data are using what type of algorithm?
a.
ciphered
b.
single
c.
asymmetric
d.
symmetric
ANSWER:
d
16. Which type of symmetric algorithm operates on plaintext one bit at a time?
a.
open ciphers
b.
plain ciphers
c.
stream ciphers
d.
block ciphers
ANSWER:
c
17. Which of the following encryption standards is part of the NSA’s suite B cryptographic algorithms and is
validated strong enough to protect classified data?
a.
DES
b.
AES-256
c.
Triple DES
d.
IDEA
ANSWER:
b
18. What encryption algorithm can be used for both encryption and digital signing, uses a one-way function,
and is still widely used in e-commerce?
a.
ECC
b.
RSA
c.
DES
d.
AES
ANSWER:
b
19. What encryption algorithm is efficient requiring few resources, and is based on complex algebra and
calculations on curves?
a.
RSA
b.
DES
c.
ECC
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d.
IDEA
ANSWER:
c
20. Which of the following is a function that takes a variable-length string or message and produces a fixed-
length message digest?
a.
RSA algorithm
b.
hashing algorithm
c.
data algorithm
d.
VLS algorithm
ANSWER:
b
21. A certificate contains a unique serial number and must follow which standard that describes the creating of a
certificate?
a.
NIST
b.
IEEE 802
c.
PKI
d.
X.509
ANSWER:
d
22. In what type of attack does the attacker have the ciphertext of several messages that were encrypted with the
same encryption algorithm, but has no access to the plaintext so he or she must try to calculate the key used to
encrypt the data?
a.
chosen-ciphertext
b.
chosen-plaintext
c.
known plaintext
d.
ciphertext-only
ANSWER:
d
23. What type of attack is being performed when the attacker has access to plaintext and ciphertext, and can
choose which messages to encrypt?
a.
chosen-ciphertext
b.
chosen-plaintext
c.
known plaintext
d.
ciphertext-only
ANSWER:
b
24. What type of attack is being conducted when the attacker has messages in both encrypted form and
decrypted forms?
a.
chosen-ciphertext
b.
chosen-plaintext
c.
known plaintext
d.
ciphertext-only
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ANSWER:
c
25. In what type of attack does the attacker need access to the cryptosystem, and the ciphertext to be decrypted
to yield the desired plaintext results?
a.
chosen-ciphertext
b.
chosen-plaintext
c.
known plaintext
d.
ciphertext-only
ANSWER:
a
26. What type of attack is being attempted when an attacker uses a password-cracking program to guess
passwords by attempting every possible combination of letters?
a.
brute force
b.
replay
c.
ciphertext-only
d.
dictionary
ANSWER:
a
27. When an attacker has access to a password file, they can run a password-cracking program that uses a
dictionary of known words or passwords as an input file. What type of attack is this attacker performing?
a.
brute force
b.
replay
c.
ciphertext-only
d.
dictionary
ANSWER:
d
28. What type of attack is being performed when an attacker intercepts the initial communications between a
Web server and a Web browser while forcing a vulnerable server to insecurely renegotiate the encryption being
used down to a weaker cipher?
a.
Cross Server attack
b.
SSL/TLS downgrade attack
c.
Hydra attack
d.
TCP/IP attack
ANSWER:
b
29. Which of the following is a scripting language for Windows and Linux that performs repetitive tasks, such
as password cracking?
a.
John the Ripper
b.
Hydra (THC)
c.
Pwdump3v2
d.
EXPECT
ANSWER:
d
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banana, strawberries, and ice cubes in a blender, but if you have to reconstruct the banana, strawberries, and
30. What application is considered the original password-cracking program and is now used by many
government agencies to test for password strength?
a.
John the Ripper
b.
Hydra (THC)
c.
Pwdump3v2
d.
L0phtcrack
ANSWER:
d
31. What is an encryption algorithm?
ANSWER:
An encryption algorithm is a mathematical function or program that works with a key. The algorithm’s
strength and the key’s secrecy determine how secure the encrypted data is. In most cases, the algorithm isn’t a
secret; it’s known to the public. What is secret is the key.
32. What is cryptanalysis?
ANSWER:
As long as people attempt to create encryption algorithms to protect data, others will endeavor to break those
encryption algorithms. This study is called cryptanalysis. It’s taught in universities and by government
organizations, but hackers also find the challenge of breaking an encryption algorithm intriguing and continue
to push the envelope for developers of encryption algorithms. When a new encryption algorithm is developed,
cryptanalysis is performed on it to ensure that breaking the code is impossible or would take so much time and
so many resources to break that it would be impractical for hackers to attempt.
33. What is Triple Data Encryption Standard (3DES)?
ANSWER:
Triple Data Encryption Standard (3DES) served as a quick fix for the vulnerabilities of DES. To make it more
difficult for attackers to crack the encryption code, 3DES performs the original DES computation three times
with different keys. This more complex computation on data makes 3DES much stronger than DES.
34. What is the RC5 algorithm?
ANSWER:
RC5 is a block cipher that can operate on different block sizes: 32, 64, or 128 bits. The key size can reach
2048 bits. The algorithm was created by Ronald L. Rivest in 1994 for RSA Security.
35. What is the difference between a public key and a private key?
ANSWER:
A public key is openly available; in many cases, public keys can be downloaded from Web sites for the public
to use. A private key is a secret key known only by the key owner and should never be shared.
36. How can confidentiality and authentication be achieved using public key cryptography?
ANSWER:
If confidentiality is a major concern for User A, she encrypts the message with the recipient’s public key. That
way, only the recipient can decrypt the message with his private key. If User A wants to assure User B that she
is indeed the person sending the message (authentication), she can encrypt the message with her private key.
After all, she’s the only person who possesses her private key.
37. What is a one-way function? Provide an example or an analogy to help explain the concept.
ANSWER:
A one-way function is a mathematical formula that’s easy to compute in one direction but difficult or nearly
impossible to compute in the opposite direction to generate a key. For example, multiplying two large prime
numbers to determine their product is easy, but when you’re given only the product, determining what
numbers were used in the calculation is difficult. A simple analogy is making a smoothie. It’s easy to blend a
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Page 8
45. Used for verification, takes a variable-length input and converts it to a fixed-length output string
ANSWER:
e
46. Used to find the same hash value for two different inputs and reveal any mathematical weaknesses in a
hashing algorithm
ANSWER:
f
47. Operate on plaintext one bit at a time
ANSWER:
g
48. A structure consisting of programs, protocols, and security policies for encrypting data and uses public key
cryptography to protect data transmitted over the Internet
ANSWER:
h
49. A sequence of random bits generated from a range of allowable values
ANSWER:
i
50. The use of random data alongside plaintext as an input to a hashing function so that the output is unique
ANSWER:
j