EC-COUNCIL EC-COUNCIL Certifications 212-81 Questions & Answers

• Question 91:

  This hash function uses 512-bit blocks and implements preset constants that change after each repetition. Each block is hashed into a 256-bit block through four branches that divides each 512 block into sixteen 32-bit words that are further encrypted and rearranged.

  A. SHA-256

  B. FORK-256

  C. SHA-1

  D. RSA

  Correct Answer: B

  FORK-256 https://en.wikipedia.org/wiki/FORK-256 FORK-256 was introduced at the 2005 NIST Hash workshop and published the following year.[6] FORK-256 uses 512-bit blocks and implements preset constants that change after each repetition. Each block is hashed into a 256-bit block through four branches that divides each 512 block into sixteen 32-bit words that are further encrypted and rearranged.

• Question 92:

  Which one of the following wireless standards uses the Advanced Encryption Standard (AES) using the Counter Mode-Cipher Block Chaining (CBC)-Message Authentication Code (MAC) Protocol (CCMP)?

  A. WEP

  B. WEP2

  C. WPA

  D. WPA2

  Correct Answer: D

  WPA2

  https://en.wikipedia.org/wiki/Wi-Fi_Protected_Access#WPA2 WPA2 use the Counter Mode-Cipher Block Chaining (CBC)-Message Authentication Code (MAC) Protocol (CCMP).

• Question 93:

  What is a "Collision attack" in cryptography?

  A. Collision attacks try to break the hash into three parts to get the plaintext value

  B. Collision attacks try to get the public key

  C. Collision attacks try to break the hash into two parts, with the same bytes in each part to get the private key

  D. Collision attacks try to find two inputs producing the same

  Correct Answer: D

  Collision attacks try to find two inputs producing the same https://en.wikipedia.org/wiki/Collision_attack

  A collision attack on a cryptographic hash tries to find two inputs producing the same hash value, i.e. a hash collision. This is in contrast to a preimage attack where a specific target hash value is specified.

• Question 94:

  Fred is using an operating system that stores all passwords as an MD5 hash. What size is an MD5 message digest (hash)?

  A. 160

  B. 512

  C. 256

  D. 128

  Correct Answer: D

  https://en.wikipedia.org/wiki/MD5

  The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value.

• Question 95:

  Changes to one character in the plain text affect multiple characters in the cipher text, unlike in historical algorithms where each plain text character only affect one cipher text character.

  A. Substitution

  B. Avalanche

  C. Confusion

  D. Diffusion

  Correct Answer: D

  Diffusion https://en.wikipedia.org/wiki/Confusion_and_diffusion Diffusion means that if we change a single bit of the plaintext, then (statistically) half of the bits in the ciphertext should change, and similarly, if we change one bit of the ciphertext, then approximately one half of the plaintext bits should change.[2] Since a bit can have only two states, when they are all re-evaluated and changed from one seemingly random position to another, half of the bits will have changed state. The idea of diffusion is to hide the relationship between the ciphertext and the plain text. This will make it hard for an attacker who tries to find out the plain text and it increases the redundancy of plain text by spreading it across the rows and columns; it is achieved through transposition of algorithm and it is used by block ciphers only.

• Question 96:

  An authentication method that periodically re-authenticates the client by establishing a hash that is then resent from the client is called ______.

  A. CHAP

  B. SPAP

  C. PAP

  D. EAP

  Correct Answer: A

  CHAP https://en.wikipedia.org/wiki/Challenge-Handshake_Authentication_Protocol Challenge-Handshake Authentication Protocol (CHAP) is an identity verification protocol that does not rely on sending a shared secret between the access-requesting party and the identity-verifying party (the authenticator). CHAP is based on a shared secret, but in order to authenticate, the authenticator sends a "challenge" message to the access-requesting party, which responds with a value calculated using a "one-way hash" function that takes as inputs the challenge and the shared secret. The authenticator checks the response against its own calculation of the expected hash value. If the values match, the authentication succeeds, otherwise it fails. Following the establishment of an authenticated connection, the authenticator may send a challenge to the access-requesting party at random intervals, to which the access-requesting party will have to produce the correct response.

• Question 97:

  The ATBASH cipher is best described as what type of cipher?

  A. Asymmetric

  B. Symmetric

  C. Substitution D. Transposition

  Correct Answer: C

  Substitution https://en.wikipedia.org/wiki/Atbash Atbash is a monoalphabetic substitution cipher originally used to encrypt the Hebrew alphabet. It can be modified for use with any known writing system with a standard collating order.

• Question 98:

  A number that is used only one time, then discarded is called what?

  A. IV

  B. Nonce

  C. Chain

  D. Salt

  Correct Answer: B

  Nonce https://en.wikipedia.org/wiki/Cryptographic_nonce A nonce is an arbitrary number that can be used just once in a cryptographic communication. It is similar in spirit to a nonce word, hence the name. It is often a random or pseudo-random number issued in an authentication protocol to ensure that old communications cannot be reused in replay attacks.

• Question 99:

  Hash algortihm created by the Russians. Produces a fixed length output of 256bits. Input message is broken up into 256 bit blocks. If block is less than 256 bits then it is padded with 0s.

  A. TIGER

  B. GOST

  C. BEAR

  D. FORK-256

  Correct Answer: B

  GOST https://en.wikipedia.org/wiki/GOST_(hash_function) The GOST hash function, defined in the standards GOST R 34.11-94 and GOST 34.311- 95 is a 256-bit cryptographic hash function. It was initially defined in the Russian national standard GOST R 34.11-94 Information Technology ?Cryptographic Information Security ?Hash Function. The equivalent standard used by other member-states of the CIS is GOST 34.311-95.

• Question 100:

  What is an IV?

  A. Random bits added to a hash

  B. The key used for a cryptography algorith

  C. A fixed size random stream that is added to a block cipher to increase randomeness

  D. The cipher used

  Correct Answer: C

  A fixed size random stream that is added to a block cipher to increase randomeness https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Initialization_vector_(IV) An initialization vector (IV) or starting variable (SV) is a block of bits that is used by several modes to randomize the encryption and hence to produce distinct ciphertexts even if the same plaintext is encrypted multiple times, without the need for a slower re-keying process.