Chapter 9 (Test 3)
In a known-plaintext attack (KPA), the cryptanalyst has access only to a segment of encrypted data, and has no choice as to what that data might be. True or False?
False
Product cipher is an encryption algorithm that has no corresponding decryption algorithm. True or False?
False
The term differential cryptanalyst refers to the act of unscrambling ciphertext into plaintext. True or False?
False
Unencrypted information is ciphertext. True or False?
False
Unlike symmetric key algorithms, asymmetric algorithms can be fast and are well suited to encrypting lots of data. True or False?
False
A substitution cipher replaces bits, characters, or blocks of information with other bits, characters, or blocks. True or False?
True
An algorithm to encrypt or decrypt information is the definition of cipher. True or False?
True
An asymmetric distribution system has no need for couriers, back channels, or expensive storage or inventory plans. True or False?
True
Chosen-ciphertext attacks have particular uses in attacking encrypted e-mail. True or False?
True
Chosen-plaintext attacks have particular uses in attacking encrypted e-mail. True or False?
True
Digital signatures require asymmetric key cryptography. True or False?
True
Cryptography accomplishes four security goals: nonrepudiation, integrity, authentication, and __________________. a. confidentiality b. security c. reliability d. privacy
a. confidentiality
What term is used to describe an encryption algorithm that has no corresponding decryption algorithm? a. one-way algorithm b. private (symmetric) key c. cipher d. cubsititution cipher
a. one-way algorithm
Which of the following is the definition of Vigenerecipher? b. An encryption cipher that shifts each letter in the English alphabet a fixed number of positions, with Z wrapping back to A c. An encyrption cipher that is a product cipher with a 56-bit key consisting of 16 iterations of substitution and transformation d. An encryption cipher that replaces bits, characters, or blocks of information with other bits, characters, or blocks
a. Uses multiple encryption schemes in succession
In a ___________, the cryptanalyst can encrypt any information and observe the output. This is best for he cryptanalyst. a. chosen-plaintext attack b. chosen-ciphertext attack c. ciphertext-only attack (COA) d. known-plaintext attack (KPA)
a. chosen-plaintext attack
A process that creates the first secure communications session between a client and a server is the definition of _____________. a. salt value b. SSL handshake c. certificate authority (CA) d. nonrepudiation
b. SSL handshake
Without any knowledge of the key, an attacker with access to an encrypted message and decryption cipher could try every possible key to decode the message. This is referred to as _______________. a. cryptanalysis b. brute-force attack c. decryption d. breaking codes
b. brute-force attack
A crypto accelerator offloads cryptographic routines from the main processor to cards that have chipsets designed for fast encryption. True or False?
True
Increasing the key length generally increases the security of a substitution cipher. True or False?
True
Symmetric key cryptography is a type of cryptography that cannot secure correspondence until after the two parties exchange keys. True or False?
True
The goal of cryptography is to make the cost or the time required to decrypt a message without the key excess the value of the protected information. True or False?
True
What term is used to describe a type of cryptography that uses a cipher with two separate keys, one for encryption and one for decryption, so that correspondents do not first have to exchange secret information to communicate securely? a. symmetric key cryptography b. asymmetric key cryptography c. key distribution d. hash
b. asymmetric key cryptography
Organizations currently use several algorithms, including ___________, which is a substitution-permutation algorithm similar to DES. Unlike DES, its authors made its design criteria public. This 64-bit symmetric block cipher can use keys from 40 to 256 bits. Although it is patented, its inventors, C.M. Adams and S.E. Tavares, made it available for free use. a. RC2 b. CAST c. International Data Encryption Algorithm (IDEA) d. blowfish
b. cast
The number of possible keys to a cipher is a ______________. a. cryptosystem b. keyspace c. checksum d. key directory
b. keyspace
What name is given to a an encryption cipher that uniquely maps any letter to any other letter? a. product cipher b. simple substitution cipher c. standard cipher d. transposition cipher
b. simple substitution cipher
A ____________ is one of the simplest substitution ciphers. IT shifts each letter in the English alphabet a fixed number of positions, with Z wrapping back to A. a. transposition cipher b. vigenere cipher c. caesar cipher d. product cipher
c. Caesar cipher
The most scrutinized cipher in history is the _____________. a. transposition cipher b. vigenere cipher c. Data Encryption Standard (DES) d. keyword mixed alphabet cipher
c. Data Encryption Standard (DES)
There are four basic forms of cryptographic attack. In a __________, the cryptanalyst has access only to a segment of encrypted data, and has no choice as to what that data might be. a. known-plaintext attack (KPA) b. chosen-ciphertext attack c. ciphertext-only attack (COA) d. chosen-plaintext attack
c. ciphertext-only attack (COA)
The number of possible keys to a cipher is a ___________. a. key directory b. cryptosystem c. keyspace d. checksum
c. keyspace
Cryptography accomplishes four security goals: confidentiality, integrity, authentication, and _______________. a. security b. reliability c. nonrepudiation d. privacy
c. nonrepudiation
_____________ enables you to prevent a party from denying a previous statement or action. a. authentication b. confidentiality c. nonrepudiation d. integrity
c. nonrepudiation
_______________ is another symmetric algorithm that organizations currently use. It is a 64-bit block cipher that has a variable key length from 32 to 448 bits. It is much faster than DES or IDEA and is a strong algorithm that has been included in more than 150 products, as well as v2.5.47 of the Linux kerne. Its author, Bruce Schneier, placed it in the public domain. a. CAST b. RC4 c. RC2 d. blowfish
d. blowfish
In a ____________, cryptanalysts submit data coded with the same cipher and key they are trying to break to the decryption device to see either the plaintext output or the effect the decrypted message has on some system. a. known-plaintext attack (KPA) b. chosen-plaintext attack c. ciphertext-only attack (COA) d. chosen-ciphertext attack
d. chosen-ciphertext attack
In a __________, the cryptanalyst can encrypt any information and observe the output. This is best for the cryptanalyst. a. known-plaintext attack (KPA) b. chosen-ciphertext attack c. ciphertext-only attack (COA) d. chosen-plaintext attack
d. chosen-plaintext attack
In a _____________, the cryptanalyst possesses certain pieces of information before and after encryption. a. chosen-ciphertext attack b. chosen-plaintext attack c. ciphertext-only attack (COA) d. known-plaintext attack (KPA)
d. known-plaintext attack (KPA)
What name is given to random characters that you can combine with an actual input key to create an encryption key? a. private key b. hash c. checksum d. salt value
d. salt value
What name is given to random characters that you can combine with an actual input key to create the encryption key? a. private key b. checksum c. hash d. salt value
d. salt value
