Important Eccouncil 212-81 ECES Exam Questions

Answer: B

Explanation:

The ciphertext block is encrypted then the ciphertext produced is XOR'd back with the plaintext to produce the current ciphertext block

https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Cipher_feedback_(CFB)

The cipher feedback (CFB) mode, a close relative of CBC, makes a block cipher into a self-synchronizing stream cipher.

Answer: A

Explanation:

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.

Incorrect answers:

EAP - A framework that allows for creation of different ways to provide authentication, such as smart cards

SPAP - Shiva Password Authentication Protocol, PAP with encryption for the usernames/passwords that are transmitted.

PAP - Password Authentication Protocol. Used to authenticate users, but is no longer used because the information was sent in cleartext.

Answer: D

Explanation:

128

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

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

Answer: C

Explanation:

RSA

The RSA encryption algorithm is one of the most widely used public key encryption algorithms that have ever been invented. It was created by the three scientists Ronald Rivest, Adi Shamir, and Leonard Adleman in 1977, and today it is increasingly being used in the network area.

Incorrect answers:

Caesar Cipher - Monoalphabetic cipher where letters are shifted one or more letters in either direction. The method is named after Julius Caesar, who used it in his private correspondence.

Vigenere - Multi alphabet cipher Invented by Giovan Battista Bellaso in middle 1553. Vigenere created a stronger version of the cipher. Combining/Weaving Caesar cipher. Not cracked until late 1800s. Widely used from 16th century to early 20th century. It is a cipher square with A to Z across all the columns and rows. You then use a keyword to encrypt the message

DES - The Data Encryption Standard is a symmetric-key algorithm for the encryption of digital data.

Answer: C

Explanation:

They are faster

Symmetric key encryption is much faster than asymmetric key encryption, because both the sender and the recipient of a message to use the same secret key.