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

• Question 111:

  Which of the following equations is related to EC?

  A. P = Cd%n

  B. Me%n

  C. y^2 = x^3 + Ax + B

  D. Let m = (p-1)(q-1)

  Correct Answer: C

  y^2 = x^3 + Ax + B

  https://en.wikipedia.org/wiki/Elliptic-curve_cryptography For current cryptographic purposes, an elliptic curve is a plane curve over a finite field (rather than the real numbers) which consists of the points satisfying the equation:

• Question 112:

  A cryptanalysis success where the attacker deduces the secret key.

  A. Information Deduction

  B. Avalanche effect

  C. Shannon's Entropy

  D. Total Break

  Correct Answer: D

  Total Break

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

  The results of cryptanalysis can also vary in usefulness. For example, cryptographer Lars Knudsen (1998) classified various types of attack on block ciphers according to the amount and quality of secret information that was discovered:

  Total break -- the attacker deduces the secret key. Global deduction -- the attacker discovers a functionally equivalent algorithm for encryption and decryption, but without learning the key. Instance (local) deduction -- the attacker discovers

  additional plaintexts (or ciphertexts) not previously known.

  Information deduction -- the attacker gains some Shannon information about plaintexts (or ciphertexts) not previously known.

  Distinguishing algorithm -- the attacker can distinguish the cipher from a random permutation.

• Question 113:

  Which of the following is a substitution cipher used by ancient Hebrew scholars?

  A. Atbash

  B. Vigenere

  C. Caesar

  D. Scytale

  Correct Answer: A

  Atbash 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 114:

  In relationship to hashing, the term _____refers to random bits that are used as one of the inputs to the hash. Essentially the ______ is intermixed with the message that is to be hashed

  A. Vector

  B. Salt

  C. Stream

  D. IV

  Correct Answer: B

  Salt

  https://en.wikipedia.org/wiki/Salt_(cryptography)

  A salt is random data that is used as an additional input to a one-way function that hashes data, a password or passphrase. Salts are used to safeguard passwords in storage. Historically a password was stored in plaintext on a system, but

  over time additional safeguards were developed to protect a user's password against being read from the system. A salt is one of those methods.

• Question 115:

  Network of trusted certificate authority servers. Use asymmetric key pairs and combines software, encryption and services to provide a means of protecting security of business communication and transactions.

  A. PKI

  B. GOST

  C. CA

  D. PIKE

  Correct Answer: A

  PKI https://en.wikipedia.org/wiki/Public_key_infrastructure A public key infrastructure (PKI) is a set of roles, policies, hardware, software and procedures needed to create, manage, distribute, use, store and revoke digital certificates and manage public-key encryption. The purpose of a PKI is to facilitate the secure electronic transfer of information for a range of network activities such as e-commerce, internet banking and confidential email. It is required for activities where simple passwords are an inadequate authentication method and more rigorous proof is required to confirm the identity of the parties involved in the communication and to validate the information being transferred.

• Question 116:

  _____ 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

  Correct Answer: B

  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 117:

  John is responsible for VPNs at his company. He is using IPSec because it has two different modes. He can choose the mode appropriate for a given situation. What are the two modes of IPSec? (Choose two)

  A. Encrypt mode

  B. Transport mode

  C. Tunnel mode

  D. Decrypt mode

  Correct Answer: BC

  Correct answers: Transport mode and Tunnel mode

  https://en.wikipedia.org/wiki/IPsec#Modes_of_operation The IPsec protocols AH and ESP can be implemented in a host-to-host transport mode, as well as in a network tunneling mode.

• Question 118:

  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

  Menezes-Qu-Vanstone https://en.wikipedia.org/wiki/MQV MQV (Menezes-Qu-Vanstone) is an authenticated protocol for key agreement based on the Diffie-Hellman scheme. Like other authenticated Diffie-Hellman 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 119:

  If the round function is a cryptographically secure pseudorandom function, then ___________ rounds is sufficient to make the block cipher a pseudorandom permutation.

  A. 2

  B. 15

  C. 16

  D. 3

  Correct Answer: D

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

  Michael Luby and Charles Rackoff analyzed the Feistel cipher construction, and proved that if the round function is a cryptographically secure pseudorandom function, with Ki used as the seed, then 3 rounds are sufficient to make the block

  cipher a pseudorandom permutation, while 4 rounds are sufficient to make it a "strong" pseudorandom permutation (which means that it remains pseudorandom even to an adversary who gets oracle access to its inverse permutation).

  Because of this very important result of Luby and Rackoff, Feistel ciphers are sometimes called Luby-Rackoff block ciphers.

• Question 120:

  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

  Correct Answer: D

  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.