Testout Chapter 3 Section 1-3 Quizzes

When an attacker decrypts an encoded message using a different key than was used during encryption, what type of attack has occurred? a) Key clustering b) Replay c) Statistical d) Analytic

Key clustering

Which of the following is not true concerning symmetric key cryptography? a) The key is not shared with other communication partners. b) Both parties share the same key (which is kept secret). c) Before communications begin, both parties must exchange the shared secret key. d) Key management is easy when implemented on a large scale. e) Each pair of communicating entities requires a unique shared key.

Key management is easy when implemented on a large scale.

You are concerned about the strength of your cryptographic keys, so you implement a system that does the following: - The initial key is fed into the input of the bcrypt utility on a Linux workstation. - The bcrypt utility produces an enhanced key that is 128 bits long. The resulting enhanced key is much more difficult to crack than the original key. Which kind of encryption mechanism was used in this scenario? a) Perfect forward secrecy b) Ephemeral keys c) Key stretching d) DHE

Key stretching

In which type of attack does the attacker have access to both the plain text and the resulting cipher text, but does not have the ability to encrypt the plain text? a) Brute force b) Known plaintext c) Chosen plaintext d) Chosen cipher

Known plaintext

In a cryptographic system, what properties should the initialization vector have? (Select two.) a) Large b) Short c) Unpredictable d) Uniform e) Predictable

Large, Unpredictable

Which of the following is the weakest hashing algorithm? a) DES b) SHA-1 c) MD5 d) AES

MD5

How many keys are used with symmetric key cryptography? a) One b) Two c) Four d) Five

One

Which of the following encryption methods combines a random value with the plain text to produce the cipher text? a) Steganography b) Transposition c) Elliptic curve d) One-time pad

One-time pad

SHA-1 uses which of the following bit length hashing algorithms? a) 128-bit, 160-bit, 192-bit, 224-bit, and 256-bit b) Only 128-bit c) 224-bit, 256-bit, 384-bit, and 512-bit d) Only 160-bit

Only 160-bit

Which of the following can be classified as a "stream cipher"? a) RC4 b) AES c) Twofish d) Blowfish

RC4

Which version of the Rivest Cipher is a block cipher that supports variable bit length keys and variable bit block sizes? a) RC5 b) RSA c) RC2 d) RC4

RC5

Which of the following does not or cannot produce a hash value of 128 bits? a) MD5 b) MD2 c) SHA-1 d) RIPEMD

SHA-1

Which of the following is the strongest hashing algorithm? a) MD5 b) SHA-1 c) LANMAN d) NTLM

SHA-1

Which form of cryptanalysis focuses on the weaknesses in the supporting computing platform as a means to exploit and defeat encryption? a) Implementation attack b) Ciphertext only attack c) Statistical attack d) Analytic attack

Statistical attack

What is the cryptography mechanism which hides secret communications within various forms of data? a) Polyinstantiation b) Signals c) Steganography d) Codes

Steganography

The Enigma machine, a cryptographic tool introduced in 1944 and used in WW2, encrypted messages by replacing characters for plain text. Which type of cipher does the Enigma machine use? a) Steam b) Transposition c) Block d) Substitution

Substitution

Which of the following best describes a side-channel attack? a) The attack targets a weakness in the software, protocol, or encryption algorithm. b) The attack exploits weaknesses in a cryptosystem such as inability to produce random numbers or floating point errors. c) The attack targets the key containing a small data set. d) The attack is based on information gained from the physical implementation of a cryptosystem.

The attack is based on information gained from the physical implementation of a cryptosystem.

Why are brute force attacks always successful? a) They are platform independent b) They can be performed in a distributed parallel processing environment c) They test every possible valid combination d) They are fast

They test every possible valid combination

Which type of cipher changes the position of the characters in a plain text message? a) Block b) Transposition c) Steam d) Substitution

Transposition

Which of the following are true of Triple DES (3DES)? (Select two.) a) Can easily be broken b) Uses 64-bit blocks with 128-bit keys c) Uses a 168-bit key d) Uses the Rijndael block cipher e) Is used in IPSec

Uses a 168-bit key; Is used in IPSec

Bob Jones used the RC5 cryptosystem to encrypt a sensitive and confidential file on his notebook. He used 32 bit blocks, a 64 bit key, and he only used the selected key once. He moved the key onto a USB hard drive which was stored in a safety deposit box. Bob's notebook was stolen. Within a few days Bob discovered the contents of his encrypted file on the Internet. What is the primary reason why Bob's file was opened so quickly? a) Weak key b) A birthday attack was used c) Too small of a block size d) The decryption key was used to decrypt the files

Weak key

You have just downloaded a file. You create a hash of the file and compare it to the hash posted on the Web site. The two hashes match. What do you know about the file? a) No one has read the file contents as it was downloaded. b) You will be the only one able to open the downloaded file. c) You can prove the source of the file. d) Your copy is the same as the copy posted on the website.

Your copy is the same as the copy posted on the website.

Match the symmetric key distribution mechanism on the left with the appropriate description on the right. Each distribution mechanism may be used once, more than once, or not at all. Drag: - Out-of-band distribution - In-band distribution Drop: - The sender's key is sent to a recipient using a Diffie-Hellman key exchange. - The sender's key is copied to a USB drive and handed to the recipient. - The sender's key is sent to the recipient using public-key cryptography. - The sender's key is burned to a CD and handed to the recipient.

- The sender's key is sent to a recipient using a Diffie-Hellman key exchange; *In-band distribution* - The sender's key is copied to a USB drive and handed to the recipient; *Out-of-band distribution* - The sender's key is sent to the recipient using public-key cryptography; *In-band distribution* - The sender's key is burned to a CD and handed to the recipient; *In-band distribution*

If a birthday attack is successful, meaning the attacker discovers a password that generates the same hash as that captured from a user's logon credentials, which of the following is true? (Select two.) a) A collision was discovered b) The discovered password is always the same as the user's password c) The user is forced to change their password a their next logon attempt d) The discovered password will allow the attacker to log on as the user, even if it is not the same as the user's password

A collision was discovered; The discovered password will allow the attacker to log on as the user, even if it is not the same as the user's password

What type of key or keys are used in symmetric cryptography? a) A unique key for each participant b) Two unique sets of key pairs c) A single key pair d) A shared private key

A shared private key

Which of the following best describes high amplification when applied to hashing algorithms? a) Hashes produced by two different parties using the same algorithm result in the same hash value. b) A small change in the message results in a big change in the hash value. c) Dissimilar messages frequently result in the same hash value. d) Reversing the hashing function does not recover the original message.

A small change in the message results in a big change in the hash value.

You want to encrypt data on a removable storage device. Which encryption method would you choose to use the strongest method possible? a) RSA b) AES c) 3DES d) SHA-1

AES

Which of the following are true concerning the Advanced Encryption Standard (AES) symmetric block cipher? (Select two.) a) AES uses the Rijndael block cipher. b) AES uses up to 16 rounds of substitution and transposition. c) AES uses a variable-length block and key length (128-, 192-, or 256-bit keys). d) AES uses 8'128-bit keys in steps of 8 bits.

AES uses the Rijndael block cipher.; AES uses a variable-length block and key length (128-, 192-, or 256-bit keys).

Which of the following algorithms are used in symmetric encryption? (Select three.) a) AES b) Diffie-Hellman c) Blowfish d) 3DES e) El-Gamal

AES, Blowfish, 3DES

Which of the following is a form of mathematical attack against the complexity of a cryptosystem's algorithm? a) Brute force attack b) Birthday attack c) Analytic attack d) Replay attack

Analytic attack

If two different messages or files produce the same hashing digest, then a collision has occurred. What form of cryptographic attack exploits this condition? a) Adaptive chosen ciphertext attack b) Meet in the middle attack c) Birthday attack d) Statistical attack

Birthday attack

Which of the following attacks will typically take the longest amount of time to complete? a) Brute force attack b) Impersonation attack c) Replay attack d) Dictionary attack

Brute force attack

Your company produces an encryption device that lets you enter text and receive encrypted text in response. An attacker obtains one of these devices and starts inputting random plain text to see the resulting cipher text. What type of attack is this? a) Chosen cipher b) Known plaintext c) Chosen plaintext d) Brute force

Chosen plaintext

When two different messages produce the same hash value, what has occurred? a) Collision b) Hash value c) High amplification d) Birthday attack

Collision

Which of the following is considered an out-of-band distribution method for private-key encryption? a) Using a private fiber network b) Copying the key to a USB drive c) Sending a secured e-email d) Using a key distribution algorithm

Copying the key to a USB drive

Hashing algorithms are used to perform what activity? a) Provide a means to exchange small amounts of data securely over a public network b) Provide for non-repudiation c) Encrypt bulk data for communications exchange d) Create a message digest

Create a message digest

Which of the following encryption mechanisms offers the least security because of weak keys? a) IDEA b) AES c) TwoFish d) DES

DES

Which type of password attack employs a list of pre-defined passwords that it tries against a logon prompt or local copy of a security accounts database? a) Asynchronous b) Dictionary c) Salami d) Brute force

Dictionary

Which of the following is used to verify that a downloaded file has not been altered? a) Asymmetric encryption b) Hash c) Private key d) Symmetric encryption

Hash

A birthday attack focuses on what? a) Encrypted files b) E-commerce c) Hashing algorithms d) VPN links

Hashing algorithms

Which of the following password attacks adds appendages to known dictionary words? a) Dictionary b) Brute force c) Hybrid d) Analytic

Hybrid

Which of the following symmetric block ciphers does not use a variable block length? a) International Data Encryption Algorithm (IDEA) b) Elliptic Curve (EC) c) Ron's Cipher v5 (RC5) d) Advanced Encryption Standard (AES)

International Data Encryption Algorithm (IDEA)