Home / ECCouncil / 212-81

Question list

List of questions

Question 1

(0)

Software for maintaining an on-the-fly-encrypted volume. Data is automatically encrypted right before it is saved, then decrypted right after it is loaded, all w/o user intervention.

Question 2

(0)

Which of the following statements is most true regarding binary operations and encryption?

Question 3

(0)

A type of frequency analysis used to attack polyalphabetic substitution ciphers. It's used to try to discover patterns and use that information to decrypt the cipher.

Question 4

(0)

What is an IV?

Question 5

(0)

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 pse

Question 6

(0)

The most common way steganography is accomplished is via which one of the following?

Question 7

(0)

A _______ product refers to an NSA-endorsed classified or controlled cryptographic item for classified or sensitive U. S. government information, including cryptographic equipment, assembly, or comp

Question 8

(0)

The reverse process from encoding - converting the encoded message back into its plaintext format.

Question 9

(0)

Which of the following asymmetric algorithms is described by U.S. Patent 5,231,668 and FIPS 186

Question 10

(0)

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?

Question 133 - 212-81 discussion

Which one of the following best describes a process that splits the block of plaintext into two separate blocks, then applies the round function to one half, and finally swaps the two halves?

Block ciphers

Symmetric cryptography

Feistel cipher

Substitution cipher

Suggested answer: C

Explanation:

Correct answer:

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

Feistel cipher (also known as Luby--Rackoff block cipher) is a symmetric structure used in the construction of block ciphers, named after the German-born physicist and cryptographer Horst Feistel who did pioneering research while working for IBM (USA); it is also commonly known as a Feistel network. A large proportion of block ciphers use the scheme, including the US Data Encryption Standard, the Soviet-developed GOST and the more recent Blowfish and Twofish ciphers. In a Feistel cipher, encryption and decryption are very similar operations, and both consist of iteratively running a function called a 'round function' a fixed number of times.

Incorrect answers:

Symmetric cryptography - Symmetric-key algorithms are algorithms for cryptography that use the same cryptographic keys for both encryption of plaintext and decryption of ciphertext. The keys may be identical or there may be a simple transformation to go between the two keys.

Substitution cipher - is a method of encrypting by which units of plaintext are replaced with ciphertext, according to a fixed system; the 'units' may be single letters (the most common), pairs of letters, triplets of letters, mixtures of the above, and so forth. The receiver deciphers the text by performing the inverse substitution.

Block ciphers - block cipher is a deterministic algorithm operating on fixed-length groups of bits, called blocks. It uses an unvarying transformation, that is, it uses a symmetric key. They are specified elementary components in the design of many cryptographic protocols and are widely used to implement the encryption of large amounts of data, including data exchange protocols.

Show Answer

asked 18/09/2024

David Gallegos

41 questions

Your answer: A B C D

0 comments

Sorted by