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

EC-COUNCIL 212-81 Online Questions & Answers

• Question 121:

  Which of the following is the standard for digital certificates?

  A. RFC 2298
  B. X.509
  C. CRL
  D. CA
  B. X.509

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  Explanation

  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 122:

  Which of the following acts as a verifier for the certificate authority?

  A. Certificate Management system
  B. Directory management system
  C. Registration authority
  D. Certificate authority
  C. Registration authority

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  Explanation

  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 123:

  A disk you rotated to encrypt/decrypt. Created by Leon Alberti. Similar technologies were used in the Enigma machine. Considered the forefather of modern encryption.

  A. Chi Square
  B. Enigma Machine
  C. Cipher Disks
  D. Scytale Cipher
  C. Cipher Disks

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  Explanation

  Cipher disks https://en.wikipedia.org/wiki/Cipher_disk A cipher disk is an enciphering and deciphering tool developed in 1470 by the Italian architect and author Leon Battista Alberti. He constructed a device, (eponymously called the Alberti cipher disk) consisting of two concentric circular plates mounted one on top of the other. The larger plate is called the "stationary" and the smaller one the "moveable" since the smaller one could move on top of the "stationary".

• Question 124:

  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
  B. X.509

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  Explanation

  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 125:

  Which of the following is a cryptographic protocol that allows two parties to establish a shared key over an insecure channel?

  A. Elliptic Curve
  B. NMD5
  C. RSA
  D. Diffie-Hellman
  D. Diffie-Hellman

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  Explanation

  Diffie-Hellman https://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange Diffie-Hellman key exchange is a method of securely exchanging cryptographic keys over a public channel and was one of the first public-key protocols as originally conceptualized by Ralph Merkle and named after Whitfield Diffie and Martin Hellman. DH is one of the earliest practical examples of public key exchange implemented within the field of cryptography.

• Question 126:

  Ahlen is using a set of pre-calculated hashes to attempt to derive the passwords from a Windows SAM file. What is a set of pre-calculated hashes used to derive a hashed password called?

  A. Hash matrix
  B. Rainbow table
  C. Password table
  D. Hash table
  B. Rainbow table

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  Explanation

  Rainbow table https://en.wikipedia.org/wiki/Rainbow_table A rainbow table is a precomputed table for caching the output of cryptographic hash functions, usually for cracking password hashes. Tables are usually used in recovering a key derivation function (or credit card numbers, etc.) up to a certain length consisting of a limited set of characters. It is a practical example of a space璽ime tradeoff, using less computer processing time and more storage than a brute-force attack which calculates a hash on every attempt, but more processing time and less storage than a simple key derivation function with one entry per hash. Use of a key derivation that employs a salt makes this attack infeasible.

• Question 127:

  Collision resistance is an important property for any hashing algorithm. Joan wants to find a cryptographic hash that has strong collision resistance. Which one of the following is the most collisionresistant?

  A. SHA2
  B. MD5
  C. MD4
  D. PIKE
  A. SHA2

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  Explanation

  SHA2 https://en.wikipedia.org/wiki/Collision_resistance Collision resistance is a property of cryptographic hash functions: a hash function H is collision-resistant if it is hard to find two inputs that hash to the same output; that is, two inputs a and b where a b but H(a) = H(b). The pigeonhole principle means that any hash function with more inputs than outputs will necessarily have such collisions; the harder they are to find, the more cryptographically secure the hash function is. Due to the Birthday Problem, for a hash function that produces an output of length n bits, the probability of getting a collision is 1/2^n/2. So, just looking for a hash function with larger "n". 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.

• Question 128:

  DES has a key space of what?

  A. 2^128
  B. 2^192
  C. 2^64
  D. 2^56
  D. 2^56

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  Explanation

  2^56 https://en.wikipedia.org/wiki/Data_Encryption_Standard The Data Encryption Standard (DES) is a symmetric-key algorithm for the encryption of digital data. Although its short key length of 56 bits makes it too insecure for applications, it has been highly influential in the advancement of cryptography.

• Question 129:

  In 2007, this wireless security algorithm was rendered useless by capturing packets and discovering the passkey in a matter of seconds. This security flaw led to a network invasion of TJ Maxx and data theft through a technique known as wardriving.

  Which Algorithm is this referring to?

  A. Wired Equivalent Privacy (WEP)
  B. Wi-Fi Protected Access 2 (WPA2)
  C. Wi-Fi Protected Access (WPA)
  D. Temporal Key Integrity Protocol (TKIP)
  A. Wired Equivalent Privacy (WEP)

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  Explanation

  Wired Equivalent Privacy (WEP) https://en.wikipedia.org/wiki/Wired_Equivalent_Privacy#Weak_security In 2007, Erik Tews, Andrei Pychkine, and Ralf-Philipp Weinmann were able to extend Klein's 2005 attack and optimize it for usage against WEP. With the new attack it is possible to recover a 104-bit WEP key with probability 50% using only 40,000 captured packets. For 60,000 available data packets, the success probability is about 80% and for 85,000 data packets about 95%. Using active techniques like deauth and ARP re-injection, 40,000 packets can be captured in less than one minute under good conditions. The actual computation takes about 3 seconds and 3 MB of main memory on a Pentium-M 1.7 GHz and can additionally be optimized for devices with slower CPUs. The same attack can be used for 40-bit keys with an even higher success probability.

• Question 130:

  Which of the following is an asymmetric cipher?

  A. RSA
  B. AES
  C. DES
  D. RC4
  A. RSA

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  Explanation

  RSA

  https://en.wikipedia.org/wiki/RSA_(cryptosystem)

  RSA (Rivest璖hamir瑼dleman) 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. In a public-key cryptosystem, the encryption key is public and distinct from the decryption key, which is kept secret (private). An RSA user creates and publishes a public key based on two large prime numbers, along with an auxiliary value.

  The prime numbers are kept secret. Messages can be encrypted by anyone, via the public key, but can only be decoded by someone who knows the prime numbers.