Chapter 8

Question 1

1. It is important to understand the concepts and application of cryptography. Which of the following most accurately defines encryption?
   A. Changing a message so it can only be easily read by the intended recipient
   B. Using complex mathematics to conceal a message
   C. Changing a message using complex mathematics
   D. Applying keys to a message to conceal it

Answer 1

A. Changing a message so it can only be easily read by the intended recipient

Question 2

2. Which of the following is the oldest encryption method discussed in this text?
   A. PGP
   B. Multi-alphabet encryption
   C. Caesar cipher
   D. Cryptic cipher

Answer 2

C. Caesar cipher

Question 3

3. Many classic ciphers are easy to understand but not secure. What is the main problem with simple substitution?
   A. It does not use complex mathematics.
   B. It is easily broken with modern computers.
   C. It is too simple.
   D. It maintains letter and word frequency.

Answer 3

D. It maintains letter and word frequency.

Question 4

4. Classic ciphers were improved with the addition of multiple shifts (multiple substitution alphabets). Which of the following is an encryption method that uses two or more different shifts?
   A. Caesar cipher
   B. Multi-alphabet encryption
   C. DES
   D. PGP

Answer 4

B. Multi-alphabet encryption

Question 5

5. Which binary mathematical operation can be used for a simple (but unsecured) encryption method and is in fact a part of modern symmetric ciphers?
   A. Bit shift
   B. OR
   C. XOR
   D. Bit swap

Answer 5

C. XOR

Question 6

6. Why is binary mathematical encryption not secure?
   A. It does not change letter or word frequency.
   B. It leaves the message intact.
   C. It is too simple.
   D. The mathematics of it is flawed.

Answer 6

A. It does not change letter or word frequency.

Question 7

7. Which of the following is most true regarding binary operations and encryption?
   A. They are completely useless.
   B. They can form a part of viable encryption methods.
   C. They are only useful as a teaching method.
   D. They can provide secure encryption.

Answer 7

B. They can form a part of viable encryption methods.

Question 8

8. What is PGP?
   A. Pretty Good Privacy, a public key encryption method
   B. Pretty Good Protection, a public key encryption method
   C. Pretty Good Privacy, a symmetric key encryption method
   D. Pretty Good Protection, a symmetric key encryption method

Answer 8

A. Pretty Good Privacy, a public key encryption method

Question 9

9. Which of the following methods is available as an add-in for most email clients?
   A. DES
   B. RSA
   C. Caesar cipher
   D. PGP

Answer 9

D. PGP

Question 10

10. Which of the following is a symmetric key system that uses 64-bit blocks?
    A. RSA
    B. DES
    C. PGP
    D. Blowfish

Answer 10

B. DES

Question 11

11. What is the advantage of a symmetric key system using 64-bit blocks?
    A. It is fast.
    B. It is unbreakable.
    C. It uses asymmetric keys.
    D. It is complex.

Answer 11

A. It is fast.

Question 12

12. What size key does a DES system use?
    A. 64 bit
    B. 128 bit
    C. 56 bit
    D. 256 bit

Answer 12

C. 56 bit

Question 13

13. What type of encryption uses different keys to encrypt and decrypt the message?
    A. Private key
    B. Public key
    C. Symmetric
    D. Secure

Answer 13

B. Public key

Question 14

14. Which of the following methods uses a variable-length symmetric key?
    A. Blowfish
    B. Caesar
    C. DES
    D. RSA

Answer 14

A. Blowfish

Question 15

15. What should you be most careful of when looking for an encryption method to use?
    A. Complexity of the algorithm
    B. Veracity of the vendor’s claims
    C. Speed of the algorithm
    D. How long the algorithm has been around

Answer 15

D. How long the algorithm has been around

Question 16

16. Which of the following is most likely to be true of an encryption method that is advertised as unbreakable?
    A. It is probably suitable for military use.
    B. It may be too expensive for your organization.
    C. It is likely to be exaggerated.
    D. It is probably one you want to use.

Answer 16

C. It is likely to be exaggerated.

Question 17

17. Which of the following is most true regarding certified encryption methods?
    A. These are the only methods you should use.
    B. It depends on the level of certification.
    C. It depends on the source of the certification.
    D. There is no such thing as certified encryption.

Answer 17

D. There is no such thing as certified encryption.

Question 18

18. Which of the following is most true regarding new encryption methods?
    A. Never use them until they have been proven.
    B. You can use them, but you must be cautious.
    C. Use them only if they are certified.
    D. Use them only if they are rated unbreakable.

Answer 18

A. Never use them until they have been proven.