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

EC-COUNCIL 212-81 Online Questions & Answers

• Question 161:

  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
  A. IDEA

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  Explanation

  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 162:

  Which of the following is used to encrypt email and create digital signatures?

  A. DES
  B. SHA1
  C. AES
  D. RSA
  D. RSA

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  Explanation

  RSA https://en.wikipedia.org/wiki/RSA_(cryptosystem) RSA use for encryption email and create digital signatures

• Question 163:

  Cylinder tool. Wrap leather around to decode. The diameter is the key. Used in 7th century BC by greek poet Archilochus.

  A. Cipher disk
  B. Caesar cipher
  C. Scytale
  D. Enigma machine
  C. Scytale

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  Explanation

  Scytale https://en.wikipedia.org/wiki/Scytale A scytale is a tool used to perform a transposition cipher, consisting of a cylinder with a strip of parchment wound around it on which is written a message. The ancient Greeks, and the Spartans in particular, are said to have used this cipher in 7th century BC to communicate during military campaigns. The recipient uses a rod of the same diameter on which the parchment is wrapped to read the message. It has the advantage of being fast and not prone to mistakes--a necessary property when on the battlefield. It can, however, be easily broken. Since the strip of parchment hints strongly at the method, the ciphertext would have to be transferred to something less suggestive, somewhat reducing the advantage noted.

• Question 164:

  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.

  A. CFB
  B. GOST
  C. ECB
  D. RC4
  C. ECB

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  Explanation

  ECB https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation The simplest of the encryption modes is the electronic codebook (ECB) mode (named after conventional physical codebooks). The message is divided into blocks, and each block is encrypted separately. The disadvantage of this method is a lack of diffusion. Because ECB encrypts identical plaintext blocks into identical ciphertext blocks, it does not hide data patterns well. ECB is not recommended for use in cryptographic protocols. ECB mode can also make protocols without integrity protection even more susceptible to replay attacks, since each block gets decrypted in exactly the same way.

• Question 165:

  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
  C. Euler's totient

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  Explanation

  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 166:

  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
  A. PKI

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  Explanation

  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 167:

  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
  B. S-PAP

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  Explanation

  S-PAP

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

• Question 168:

  Which of the following was a multi alphabet cipher widely used from the 16th century to the early 20th century?

  A. Atbash
  B. Caesar
  C. Scytale
  D. Vigenere
  D. Vigenere

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  Explanation

  Vigenere https://en.wikipedia.org/wiki/Vigen%C3%A8re_cipher The Vigen鑢e cipher is a method of encrypting alphabetic text by using a series of interwoven Caesar ciphers, based on the letters of a keyword. It employs a form of polyalphabetic substitution. First described by Giovan Battista Bellaso in 1553, the cipher is easy to understand and implement, but it resisted all attempts to break it until 1863, three centuries later. This earned it the description le chiffre ind閏hiffrable (French for 'the indecipherable cipher'). Many people have tried to implement encryption schemes that are essentially Vigen鑢e ciphers. In 1863, Friedrich Kasiski was the first to publish a general method of deciphering Vigen鑢e ciphers.

• Question 169:

  Used to take the burden off of a CA by handling verification prior to certificates being issued. Acts as a proxy between user and CA. Receives request, authenticates it and forwards it to the CA.

  A. PKI (Public Key Infrastructure)
  B. TTP (Trusted Third Party)
  C. RA (Registration Authority)
  D. CP (Certificate Policy)
  C. RA (Registration Authority)

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  Explanation

  RA (Registration Authority)

  https://en.wikipedia.org/wiki/Registration_authority Registration authorities exist for many standards organizations, such as ANNA (Association of National Numbering Agencies for ISIN), the Object Management Group, W3C, IEEE and others.

  In general, registration authorities all perform a similar function, in promoting the use of a particular standard through facilitating its use. This may be by applying the standard, where appropriate, or by verifying that a particular application

  satisfies the standard's tenants. Maintenance agencies, in contrast, may change an element in a standard based on set rules ?such as the creation or change of a currency code when a currency is created or revalued (i.e. TRL to TRY for

  Turkish lira). The Object Management Group has an additional concept of certified provider, which is deemed an entity permitted to perform some functions on behalf of the registration authority, under specific processes and procedures

  documented within the standard for such a role.

• Question 170:

  Which method of password cracking takes the most time and effort?

  A. Dictionary attack
  B. Shoulder surfing
  C. Brute force
  D. Rainbow tables
  C. Brute force

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  Explanation

  Brute force

  https://en.wikipedia.org/wiki/Brute-force_attack

  A brute-force attack consists of an attacker submitting many passwords or passphrases with the hope of eventually guessing correctly. The attacker systematically checks all possible passwords and passphrases until the correct one is found.

  Alternatively, the attacker can attempt to guess the key which is typically created from the password using a key derivation function. This is known as an exhaustive key search. A brute-force attack is a cryptanalytic attack that can, in theory,

  be used to attempt to decrypt any encrypted data (except for data encrypted in an information-theoretically secure manner). Such an attack might be used when it is not possible to take advantage of other weaknesses in an encryption system

  (if any exist) that would make the task easier.