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

• Question 61:

  RFC 1321 describes what hash?

  A. RIPEMD

  B. GOST

  C. SHA1

  D. MD5

  Correct Answer: D

  MD5 https://en.wikipedia.org/wiki/MD5 MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function MD4, and was specified in 1992 as RFC 1321.

• Question 62:

  A simple algorithm that will take the initial key and from that generate a slightly different key each round.

  A. Key Schedule

  B. Feistel Network

  C. SHA-2

  D. Diffie-Helman

  Correct Answer: A

  Key Schedule https://en.wikipedia.org/wiki/Key_schedule In cryptography, the so-called product ciphers are a certain kind of cipher, where the (de- )ciphering of data is typically done as an iteration of rounds. The setup for each round is generally the same, except for round-specific fixed values called a round constant, and round-specific data derived from the cipher key called a round key. A key schedule is an algorithm that calculates all the round keys from the key.

• Question 63:

  When learning algorithms, such as RSA, it is important to understand the mathematics being used. In RSA, the number of positive integers less than or equal to some number is critical in key generation. The number of positive integers less than or equal to n that are coprime to n is called ______.

  A. Mersenne's number

  B. Fermat's number

  C. Euler's totient

  D. Fermat's prime

  Correct Answer: C

  Euler's totient

  https://en.wikipedia.org/wiki/Euler%27s_totient_function In number theory, Euler's totient function counts the positive integers up to a given integer n that are relatively prime to n.

• Question 64:

  What is a variation of DES that uses a technique called Key Whitening?

  A. Blowfish

  B. DESX

  C. 3DES

  D. AES

  Correct Answer: B

  DESX https://en.wikipedia.org/wiki/DES-X In cryptography, DES-X (or DESX) is a variant on the DES (Data Encryption Standard) symmetric-key block cipher intended to increase the complexity of a brute-force attack using a technique called key whitening.

• Question 65:

  Which algorithm implements an unbalanced Feistel cipher?

  A. Skipjack

  B. RSA

  C. 3DES

  D. Blowfish

  Correct Answer: A

  Skipjack

  https://en.wikipedia.org/wiki/Skipjack_(cipher)

  Skipjack uses an 80-bit key to encrypt or decrypt 64-bit data blocks. It is an unbalanced Feistel network with 32 rounds.

• Question 66:

  What does the OCSP protocol provide?

  A. Revoked certificates

  B. Hashing

  C. VPN connectivity

  D. Encryption

  Correct Answer: A

  Revoked certificates https://en.wikipedia.org/wiki/Online_Certificate_Status_Protocol The Online Certificate Status Protocol (OCSP) is an Internet protocol used for obtaining the revocation status of an X.509 digital certificate.It is described in RFC 6960 and is on the Internet standards track. It was created as an alternative to certificate revocation lists (CRL), specifically addressing certain problems associated with using CRLs in a public key infrastructure (PKI). Messages communicated via OCSP are encoded in ASN.1 and are usually communicated over HTTP. The "request/response" nature of these messages leads to OCSP servers being termed OCSP responders.

• Question 67:

  How did the ATBASH cipher work?

  A. By substituting each letter for the letter from the opposite end of the alphabet (i.e. A becomes Z, B becomes Y, etc.)

  B. By rotating text a given number of spaces

  C. By Multi alphabet substitution

  D. By shifting each letter a certain number of spaces

  Correct Answer: A

  By substituting each letter for the letter from the opposite end of the alphabet (i.e. A becomes Z, B becomes Y, etc.)

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

  The Atbash cipher is a particular type of monoalphabetic cipher formed by taking the alphabet (or abjad, syllabary, etc.) and mapping it to its reverse, so that the first letter becomes the last letter, the second letter becomes the second to last

  letter, and so on.

• Question 68:

  This is a proprietary version of PAP. Encrypts username and password as it is sent across network.

  A. PPTP VPN

  B. S-PAP

  C. Kerberos

  D. WPA2

  Correct Answer: B

  S-PAP

  Shiva Password Authentication Protocol (S-PAP) - PAP with encryption for the usernames/passwords that are transmitted.

• Question 69:

  Jane is looking for an algorithm to ensure message integrity. Which of following would be an acceptable choice?

  A. RSA

  B. AES

  C. RC4

  D. SHA-1

  Correct Answer: D

  Integrity. In information security, data integrity means maintaining and assuring the accuracy and completeness of data over its entire lifecycle. This means that data cannot be modified in an unauthorized or undetected manner. An important application of hashes is verification of message integrity. Comparing message digests (hash digests over the message) calculated before, and after, transmission can determine whether any changes have been made to the message or file. SHA-1 https://en.wikipedia.org/wiki/SHA-1 SHA-1 (Secure Hash Algorithm 1) is a cryptographic hash function which takes an input and produces a 160-bit (20-byte) hash value known as a message digest ?typically rendered as a hexadecimal number, 40 digits long. It was designed by the United States National Security Agency, and is a U.S. Federal Information Processing Standard.

• Question 70:

  Protocol suite provides a method of setting up a secure channel for protected data exchange between two devices.

  A. CLR

  B. OCSP

  C. TLS

  D. IPSec

  Correct Answer: D

  IPSec https://en.wikipedia.org/wiki/IPsec Internet Protocol Security (IPsec) is a secure network protocol suite that authenticates and encrypts the packets of data to provide secure encrypted communication between two computers over an Internet Protocol network. It is used in virtual private networks (VPNs).