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

• Question 51:

  Which one of the following is a component of the PKI?

  A. CA

  B. TGS

  C. OCSP

  D. TGT

  Correct Answer: A

  CA https://en.wikipedia.org/wiki/Certificate_authority Certificate authority or certification authority (CA) is an entity that issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate. This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key. A CA acts as a trusted third party--trusted both by the subject (owner) of the certificate and by the party relying upon the certificate. The format of these certificates is specified by the X.509 or EMV standard.

• Question 52:

  Which of the following are required for a hash? (Choose two)

  A. Not vulnerable to a brute force attack

  B. Few collisions

  C. Must use SALT

  D. Not reversible

  E. Variable length input, fixed length output

  F. Minimum key length

  Correct Answer: DE

  Correct answers: Variable length input, fixed length output and Not reversible https://en.wikipedia.org/wiki/Hash_function A hash function is any function that can be used to map data of arbitrary size to fixed-size values. The values returned by a hash function are called hash values, hash codes, digests, or simply hashes. The values are used to index a fixed-size table called a hash table. Use of a hash function to index a hash table is called hashing or scatter storage addressing.

• Question 53:

  Created by D. H. Lehmer. It is a classic example of a Linear congruential generator. A PRNG type of linear congruential generator (LCG) that operates in multiplicative group of integers modulo n. The basic algorithm is Xi+1=(aXi + c) mod m, with 0 Xi m.

  A. Lehmer Random Number Generator

  B. Lagged Fibonacci Generator

  C. Linear Congruential Generator

  D. Blum Blum Shub

  Correct Answer: A

  Lehmer Random Number Generator https://en.wikipedia.org/wiki/Lehmer_random_number_generator The Lehmer random number generator (named after D. H. Lehmer), sometimes also referred to as the Park璏iller random number generator (after Stephen K. Park and Keith

  W. Miller), is a type of linear congruential generator (LCG) that operates in multiplicative group of integers modulo n. The general formula is:

  where the modulus m is a prime number or a power of a prime number, the multiplier a is an element of high multiplicative order modulo m (e.g., a primitive root modulo n), and the seed X0 is coprime to m. Other names are multiplicative linear congruential generator (MLCG) and multiplicative congruential generator (MCG).

• Question 54:

  Which service in a PKI will vouch for the identity of an individual or company?

  A. CA

  B. CR

  C. KDC

  D. CBC

  Correct Answer: A

  CA

  https://en.wikipedia.org/wiki/Certificate_authority A certificate authority or certification authority (CA) is an entity that issues digital certificates. A digital certificate certifies the ownership of a public key by the named subject of the certificate.

  This allows others (relying parties) to rely upon signatures or on assertions made about the private key that corresponds to the certified public key. A CA acts as a trusted third party--trusted both by the subject (owner) of the certificate and by

  the party relying upon the certificate. The format of these certificates is specified by the X.509 or EMV standard.

• Question 55:

  Which one of the following are characteristics of a hash function? (Choose two)

  A. Requires a key

  B. One-way

  C. Fixed length output

  D. Symmetric

  E. Fast

  Correct Answer: BC

  Correct answers: One-way, Fixed length output https://en.wikipedia.org/wiki/Cryptographic_hash_function A cryptographic hash function is a mathematical algorithm that maps data of arbitrary size (often called the "message") to a bit array of a fixed size (the "hash value", "hash", or "message digest"). It is a one-way function, that is, a function which is practically infeasible to invert.

• Question 56:

  Which analysis type is based on the statistics of the numbers of unique colors and close- color pairs in a 24-bit image, a method that analyzes the pairs of colors created by LSB embedding?

  A. Differential Analysis

  B. Discrete Cosine Transform

  C. Raw Quick Pair

  D. Chi squared analysis

  Correct Answer: C

  Raw Quick Pair https://www.cs.auckland.ac.nz/courses/compsci725s2c/archive/termpapers/yy.pdf Du and Long2 (2000) introduced Raw Quick Pairs detecting method of Stego-images (the images that contain the steganographic message). The underlying principle of the method is that the number of close color pairs of Stego-images will be larger compare with the number of close color pairs of normal images. In contrast, Fridrich and Goljan (2001) pointed out that RQP method only works if the number of unique colors is relatively low; and the method can not be applied to grayscale images. However, this paper will outline the core principle of RQP method; and evaluate such critical comments in details. In addition, this paper suggests potential improvement of RQP method and provides one possible alternative.

• Question 57:

  Symmetric algorithm. Designed by James Massey and Xuejia Lai. Operates on 64 bit blocks and has a 128 bit key. Consists of 8 identical transformations each round and an output transformation.

  A. IDEA

  B. RSA

  C. CAST

  D. DES

  Correct Answer: A

  IDEA https://en.wikipedia.org/wiki/International_Data_Encryption_Algorithm In cryptography, the International Data Encryption Algorithm (IDEA), originally called Improved Proposed Encryption Standard (IPES), is a symmetric-key block cipher designed by James Massey of ETH Zurich and Xuejia Lai and was first described in 1991. The algorithm was intended as a replacement for the Data Encryption Standard (DES). IDEA is a minor revision of an earlier cipher Proposed Encryption Standard (PES). The cipher was designed under a research contract with the Hasler Foundation, which became part of Ascom-Tech AG. The cipher was patented in a number of countries but was freely available for noncommercial use. The name "IDEA" is also a trademark. The last patents expired in 2012, and IDEA is now patent-free and thus completely free for all uses. IDEA was used in Pretty Good Privacy (PGP) v2.0 and was incorporated after the original cipher used in v1.0, BassOmatic, was found to be insecure. IDEA is an optional algorithm in the OpenPGP standard.

• Question 58:

  You are explaining the details of the AES algorithm to cryptography students. You are discussing the derivation of the round keys from the shared symmetric key. The portion of AES where round keys are derived from the cipher key using Rijndael's key schedule is called what?

  A. The key expansion phase

  B. The round key phase

  C. The bit shifting phase

  D. The initial round

  Correct Answer: A

  The key expansion phase

  https://en.wikipedia.org/wiki/Advanced_Encryption_Standard KeyExpansion ?round keys are derived from the cipher key using the AES key schedule. AES requires a separate 128-bit round key block for each round plus one more.

• Question 59:

  You have been tasked with selecting a digital certificate standard for your company to use. Which one of the following was an international standard for the format and information contained in a digital certificate?

  A. CA

  B. X.509

  C. CRL

  D. RFC 2298

  Correct Answer: B

  X.509 https://en.wikipedia.org/wiki/X.509

  X.509 is a standard defining the format of public key certificates. X.509 certificates are used in many Internet protocols, including TLS/SSL, which is the basis for HTTPS, the secure protocol for browsing the web. They are also used in offline applications, like electronic signatures. An X.509 certificate contains a public key and an identity (a hostname, or an organization, or an individual), and is either signed by a certificate authority or self-signed. When a certificate is signed by a trusted certificate authority, or validated by other means, someone holding that certificate can rely on the public key it contains to establish secure communications with another party, or validate documents digitally signed by the corresponding private key.

• Question 60:

  Which component of IPsec performs protocol-level functions that are required to encrypt and decrypt the packets?

  A. IPsec Policy Agent

  B. Internet Key Exchange (IKE)

  C. Oakley

  D. IPsec driver

  Correct Answer: B

  Internet Key Exchange (IKE)

  https://en.wikipedia.org/wiki/Internet_Key_Exchange Internet Key Exchange (IKE, sometimes IKEv1 or IKEv2, depending on version) is the protocol used to set up a security association (SA) in the IPsec protocol suite. IKE builds upon the

  Oakley protocol and ISAKMP. IKE uses X.509 certificates for authentication either pre-shared or distributed using DNS (preferably with DNSSEC) and a Diffie-Hellman key exchange to set up a shared session secret from which cryptographic

  keys are derived.