Eccouncil Certified Encryption Specialist 212-81 ECES Exam Questions

Answer : C

56

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

The Data Encryption Standard 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.

Answer : A

ADFVGX Cipher

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

ADFGVX cipher was a field cipher used by the German Army on the Western Front during World War I. ADFGVX was in fact an extension of an earlier cipher called ADFGX.

Invented by Lieutenant Fritz Nebel (1891--1977) and introduced in March 1918, the cipher was a fractionating transposition cipher which combined a modified Polybius square with a single columnar transposition.

Incorrect answers:

Book Ciphers - or Ottendorf cipher, is a cipher in which the key is some aspect of a book or other piece of text. Books, being common and widely available in modern times, are more convenient for this use than objects made specifically for cryptographic purposes. It is typically essential that both correspondents not only have the same book, but the same edition.

Cipher Disk - 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'

ROT13 Cipher - simple letter substitution cipher that replaces a letter with the 13th letter after it, in the alphabet. ROT13 is a special case of the Caesar cipher which was developed in ancient Rome.

Answer : C

Answer : C

Kerkchoff's principle

https://en.wikipedia.org/wiki/Kerckhoffs%27s_principle

Kerckhoffs's principle (also called Kerckhoffs's desideratum, assumption, axiom, doctrine or law) of cryptography was stated by Netherlands born cryptographer Auguste Kerckhoffs in the 19th century: A cryptosystem should be secure even if everything about the system, except the key, is public knowledge.

Kerckhoffs's principle was reformulated (or possibly independently formulated) by American mathematician Claude Shannon as 'the enemy knows the system', i.e., 'one ought to design systems under the assumption that the enemy will immediately gain full familiarity with them'. In that form, it is called Shannon's maxim. This concept is widely embraced by cryptographers, in contrast to 'security through obscurity', which is not.

Answer : A

MQV

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).

Incorrect answers:

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.

AES - Advanced Encryption Standard (AES), also known by its original name Rijndael, is a specification for the encryption of electronic data established by the U.S. National Institute of Standards and Technology (NIST) in 2001.

DES - Data Encryption Standard is a symmetric-key algorithm for the encryption of digital data.

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.

Incorrect answers:

Scytale - Transposition cipher. A staff with papyrus or letter wrapped around it so edges would line up. There would be a stream of characters which would show you your message. When unwound it would be a random string of characters. Would need an identical size staff on other end for other individuals to decode message.

Vigenre - 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.

Caesar Cipher - Monoalphabetic cipher where letters are shifted one or more letters in either direction. The method is named after Julius Caesar, who used it in his private correspondence.

Answer : C

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.

Incorrect answers:

RC4 - stream symmetric cipher that was created by Ron Rivest of RSA. Used in SSL and WEP.

GOST - the GOST block cipher (Magma), defined in the standard GOST 28147-89 (RFC 5830), is a Soviet and Russian government standard symmetric key block cipher with a block size of 64 bits. The original standard, published in 1989, did not give the cipher any name, but the most recent revision of the standard, GOST R 34.12-2015, specifies that it may be referred to as Magma. The GOST hash function is based on this cipher. The new standard also specifies a new 128-bit block cipher called Kuznyechik.

CFB - the process wherein the ciphertext block is encrypted then the ciphertext produced is XOR'd back with the plaintext to produce the current ciphertext block.