Free EC-COUNCIL 212-81 Study Guides Exam Questions & Answer [Q43-Q65] : Exams Labs Braindumps : http://blog.examslabs.com

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Free EC-COUNCIL 212-81 Study Guides Exam Questions & Answer [Q43-Q65]

Free EC-COUNCIL 212-81 Study Guides Exam Questions and Answer

212-81 Exam Dumps, 212-81 Practice Test Questions

Q43. 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?

X.509

CRL

RFC 2298

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

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.

Q44. The most widely used asymmetric encryption algorithm is what?

Vigenere

Caesar Cipher

RSA

DES

Q45. Which of the following is an asymmetric cipher?

RSA

AES

DES

RC4

Q46. Developed by Netscape and has been replaced by TLS. It was the preferred method used with secure websites.

OCSP

VPN

CRL

SSL

SSL
https://en.wikipedia.org/wiki/Transport_Layer_Security
Transport Layer Security (TLS), and its now-deprecated predecessor, Secure Sockets Layer (SSL), are cryptographic protocols designed to provide communications security over a computer network. Several versions of the protocols find widespread use in applications such as web browsing, email, instant messaging, and voice over IP (VoIP). Websites can use TLS to secure all communications between their servers and web browsers.
Netscape developed the original SSL protocols, and Taher Elgamal, chief scientist at Netscape Communications from 1995 to 1998, has been described as the “father of SSL”. SSL version 1.0 was never publicly released because of serious security flaws in the protocol. Version 2.0, released in February 1995, contained a number of security flaws which necessitated the design of version 3.0. Released in 1996, SSL version 3.0 represented a complete redesign of the protocol produced by Paul Kocher working with Netscape engineers Phil Karlton and Alan Freier, with a reference implementation by Christopher Allen and Tim Dierks of Consensus Development.
Incorrect answers:
CRL – a list of every certificate that has been revoked.
VPN – A virtual private network (VPN) extends a private network across a public network and enables users to send and receive data across shared or public networks as if their computing devices were directly connected to the private network. Applications running across a VPN may therefore benefit from the functionality, security, and management of the private network. Encryption is a common, although not an inherent, part of a VPN connection OCSP – 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).

Q47. MD5 can best be described as which one of the following?

Asymmetric algorithm

Hashing algorithm

Digital signature

Symmetric algorithm

Q48. Which one of the following terms describes two numbers that have no common factors?

Coprime

Fermat’s number

Euler’s totient

Convergent

Q49. The Clipper chip is notable in the history of cryptography for many reasons. First, it was designed for civilian used secure phones. Secondly, it was designed to use a very specific symmetric cipher. Which one of the following was originally designed to provide built-in cryptography for the Clipper chip?

Blowfish

Twofish

Skipjack

Serpent

Q50. What does Output feedback (OFB) do:

The message is divided into blocks and each block is encrypted separately. This is the most basic mode for symmetric encryption

The cipher text from the current round is XORed with the plaintext from the previous round

A block cipher is converted into a stream cipher by generating a keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext

The cipher text from the current round is XORed with the plaintext for the next round

Q51. Part of understanding cryptography is understanding the cryptographic primitives that go into any crypto system. A(n) _______ is a fixed-size input to a cryptographic primitive that is random or pseudorandom.

Key

Chain

Salt

Q52. If Bob is using asymmetric cryptography and wants to send a message to Alice so that only she can decrypt it, what key should he use to encrypt the message?

Alice’s private key

Bob’s private key

Alice’s public key

Bob’s public key

Q53. Numbers that have no factors in common with another.

Fibonacci Numbers

Even Numbers

Co-prime numbers

Mersenne Primes

Q54. Message hidden in unrelated text. Sender and receiver have pre-arranged to use a pattern to remove certain letters from the message which leaves only the true message behind.

Caesar Cipher

Null Ciphers

Vigenere Cipher

Playfair Cipher

Q55. Encryption of the same plain text with the same key results in the same cipher text. Use of an IV that is XORed with the first block of plain text solves this problem.

CFB

GOST

ECB

RC4

Q56. The next number is derived from adding together the prior two numbers (1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89).

Odd numbers

Fibonacci Sequence

Fermat pseudoprime

Prime numbers

Q57. You are explaining basic mathematics to beginning cryptography students. You are covering the basic math used in RSA. A prime number is defined as

Odd numbers with no divisors

Odd numbers

Any number only divisible by odd numbers

Any number only divisible by one and itself

Q58. What is the solution to the equation 8 mod 3?

Q59. This is a 128 bit hash that is specified by RFC 1321. It was designed by Ron Rivest in 1991 to replace an earlier hash function.

SHA1

SHA-256

RSA

MD5

MD5
https://en.wikipedia.org/wiki/MD5
The MD5 message-digest algorithm is a widely used hash function producing a 128-bit hash value. Although MD5 was initially designed to be used as a cryptographic hash function, it has been found to suffer from extensive vulnerabilities. It can still be used as a checksum to verify data integrity, but only against unintentional corruption. It remains suitable for other non-cryptographic purposes, for example for determining the partition for a particular key in a partitioned database.
MD5 was designed by Ronald Rivest in 1991 to replace an earlier hash function MD4, and was specified in 1992 as RFC 1321.
Incorrect answers:
SHA1 – (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.
RSA – (Rivest-Shamir-Adleman) is a public-key cryptosystem that is widely used for secure data transmission. It is also one of the oldest. The acronym RSA comes from the surnames of Ron Rivest, Adi Shamir, and Leonard Adleman, who publicly described the algorithm in 1977. An equivalent system was developed secretly, in 1973 at GCHQ (the British signals intelligence agency), by the English mathematician Clifford Cocks. That system was declassified in 1997.
SHA-256 – SHA-2 (Secure Hash Algorithm 2) is a set of cryptographic hash functions designed by the United States National Security Agency (NSA) and first published in 2001. They are built using the Merkle-Damgard structure, from a one-way compression function itself built using the Davies-Meyer structure from a specialized block cipher. SHA-2 includes significant changes from its predecessor, SHA-1. The SHA-2 family consists of six hash functions with digests (hash values) that are 224, 256, 384 or 512 bits: SHA-224, SHA-256, SHA-384, SHA-512, SHA-512/224, SHA-512/256

Q60. Which of the following is a key exchange protocol?

MQV

AES

DES

RSA

Q61. With Cipher feedback (CFB) what happens?

The key is reapplied

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

The block cipher is turned into a stream cipher

The message is divided into blocks and each block is encrypted separately. This is the most basic mode for symmetric encryption

Q62. John is trying to explain the basics of cryptography to a group of young, novice, security students. Which one of the following most accurately defines encryption?

Changing a message using complex mathematics

Applying keys to a message to conceal it

Complex mathematics to conceal a message

Changing a message so it can only be easily read by the intended recipient

Q63. Manipulating individuals so that they will divulge confidential information, rather than by breaking in or using technical cracking techniques.

Linear cryptanalysis

Replay attack

Side-channel attack

Social engineering attack

Q64. Which of the following would be the fastest.

RSA

AES

Q65. During the process of encryption and decryption, what keys are shared?

Public keys

Public and private keys

User passwords

Private keys

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