EC-COUNCIL 212-81 Online Practice Questions and Exam Preparation

EC-COUNCIL 212-81 Online Questions & Answers

• Question 171:

  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
  D. Chi squared analysis

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  Explanation

  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 172:

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

  A. WEP2
  B. WPA
  C. WEP
  D. WPA2
  D. WPA2

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  Explanation

• Question 173:

  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
  D. SHA-1

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  Explanation

  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 174:

  Which of the following is not a key size used by AES?

  A. 128 bits
  B. 192 bits
  C. 256 bits
  D. 512 b
  D. 512 b

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  Explanation

  512 bits https://en.wikipedia.org/wiki/Advanced_Encryption_Standard AES is a subset of the Rijndael block cipher developed by two Belgian cryptographers, Vincent Rijmen and Joan Daemen, who submitted a proposal to NIST during the AES selection process. Rijndael is a family of ciphers with different key and block sizes. For AES, NIST selected three members of the Rijndael family, each with a block size of 128 bits, but three different key lengths: 128, 192 and 256 bits.

• Question 175:

  _____ uses at least two different shifts, changing the shift with different letters in the plain text.

  A. Caesar cipher
  B. multi-alphabet encryption
  C. Scytale
  D. Atbash
  B. multi-alphabet encryption

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  Explanation

  multi-alphabet encryption https://en.wikipedia.org/wiki/Polyalphabetic_cipher Two different shifts create two different alphabets. For +1 and +2 Plaintext alphabet A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 2 ciphertext alphabets B C D E F G H I J K L M N O P Q R S T U V W X Y Z A C D E F G H I J K L M N O P Q R S T U V W X Y Z A B

• Question 176:

  Which of the following would be the weakest encryption algorithm?

  A. DES
  B. AES
  C. RSA
  D. EC
  A. DES

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  Explanation

  DES https://en.wikipedia.org/wiki/Data_Encryption_Standard DES is insecure due to the relatively short 56-bit key size. In January 1999, distributed.net and the Electronic Frontier Foundation collaborated to publicly break a DES key in 22 hours and 15 minutes.

• Question 177:

  Terrance oversees the key escrow server for his company. All employees use asymmetric cryptography to encrypt all emails. How many keys are needed for asymmetric cryptography?

  A. 2
  B. 4
  C. 3
  D. 1
  A. 2

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  Explanation

  https://en.wikipedia.org/wiki/Public-key_cryptography Public-key cryptography, or asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be disseminated widely, and private keys, which are known

  only to the owner. The generation of such keys depends on cryptographic algorithms based on mathematical problems to produce one-way functions. Effective security only requires keeping the private key private; the public key can be

  openly distributed without compromising security.

  In such a system, any person can encrypt a message using the receiver's public key, but that encrypted message can only be decrypted with the receiver's private key.

• Question 178:

  The most widely used digital certificate standard. First issued July 3, 1988. It is a digital document that contains a public key signed by the trusted third party, which is known as a Certificate Authority, or CA. Relied on by S/MIME. Contains your name, info about you, and a signature of a person who issued the certificate.

  A. ElGamal
  B. RSA
  C. PAP
  D. X.509
  D. X.509

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  Explanation

  X.509 https://en.wikipedia.org/wiki/X.509 In cryptography, 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 179:

  A protocol for key aggreement based on Diffie-Hellman. Created in 1995. Incorporated into the public key standard IEEE P1363. A. Blum Blum Shub

  B. Elliptic Curve

  C. Menezes-Qu-Vanstone

  D. Euler's totient

  Correct Answer. C
  C

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  Explanation

  Menezes-Qu-Vanstone https://en.wikipedia.org/wiki/MQV MQV (Menezes璔u璙anstone) is an authenticated protocol for key agreement based on the Diffie璈ellman scheme. Like other authenticated Diffie璈ellman schemes, MQV provides protection against an active attacker. The protocol can be modified to work in an arbitrary finite group, and, in particular, elliptic curve groups, where it is known as elliptic curve MQV (ECMQV). MQV was initially proposed by Alfred Menezes, Minghua Qu and Scott Vanstone in 1995. It was modified with Law and Solinas in 1998.

• Question 180:

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

  A. IV
  B. Nonce
  C. Chain
  D. Salt
  B. Nonce

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  Explanation

  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.