Eccouncil Certified Encryption Specialist 212-81 ECES Exam Practice Test

Answer : C

Menezes-Qu-Vanstone

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).

MQV was initially proposed by Alfred Menezes, Minghua Qu and Scott Vanstone in 1995. It was modified with Law and Solinas in 1998.

Incorrect answers:

Elliptic Curve - an approach to public-key cryptography based on the algebraic structure of elliptic curves over finite fields. ECC allows smaller keys compared to non-EC cryptography (based on plain Galois fields) to provide equivalent security.

Euler's totient - function counts the positive integers up to a given integer n that are relatively prime to n.

Blum Blum Shub - a pseudorandom number generator proposed in 1986 by Lenore Blum, Manuel Blum and Michael Shub that is derived from Michael O. Rabin's one-way function.

Answer : A

PAP

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

Password Authentication Protocol (PAP) is a password-based authentication protocol used by Point to Point Protocol (PPP) to validate users. Almost all network operating system remote servers support PAP. PAP is specified in RFC 1334.

PAP is considered a weak authentication scheme (weak schemes are simple and have lighter computational overhead but are much more vulnerable to attack; while weak schemes may have limited application in some constrained environments, they are avoided in general). Among PAP's deficiencies is the fact that it transmits unencrypted passwords (i.e. in plain-text) over the network. PAP is therefore used only as a last resort when the remote server does not support a stronger scheme such as CHAP or EAP.

Incorrect answers:

SPAP - Shiva Password Authentication Protocol, PAP with encryption for the usernames/passwords that are transmitted.

CHAP - calculates a hash, shares the hash with the client system, the hash is periodically validated to ensure nothing has changed.

Kerberos - computer-network authentication protocol that works on the basis of tickets to allow nodes communicating over a non-secure network to prove their identity to one another in a secure manner. Its designers aimed it primarily at a client--server model and it provides mutual authentication---both the user and the server verify each other's identity. Kerberos protocol messages are protected against eavesdropping and replay attacks.

Kerberos builds on symmetric key cryptography and requires a trusted third party, and optionally may use public-key cryptography during certain phases of authentication.

Answer : A

Asymmetric

https://en.wikipedia.org/wiki/Public-key_cryptography

Asymmetric cryptography, is a cryptographic system that uses pairs of keys: public keys, which may be disseminated widely, and private keys, which are known only to the owner. The generation of such keys depends on cryptographic algorithms based on mathematical problems to produce one-way functions. Effective security only requires keeping the private key private; the public key can be openly distributed without compromising security.

Answer : D

Answer : C

Output feedback (OFB)

https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation#Output_feedback_(OFB)

The output feedback (OFB) mode makes a block cipher into a synchronous stream cipher. It generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext. Just as with other stream ciphers, flipping a bit in the ciphertext produces a flipped bit in the plaintext at the same location. This property allows many error-correcting codes to function normally even when applied before encryption.

Incorrect answers:

Cipher feedback (CFB)- mode, a close relative of CBC, makes a block cipher into a self-synchronizing stream cipher.

Electronic codebook (ECB)- the simplest of the encryption modes (named after conventional physical codebooks). The message is divided into blocks, and each block is encrypted separately.

Cipher-block chaining (CBC)- Ehrsam, Meyer, Smith and Tuchman invented the cipher block chaining (CBC) mode of operation in 1976. In CBC mode, each block of plaintext is XORed with the previous ciphertext block before being encrypted. This way, each ciphertext block depends on all plaintext blocks processed up to that point. To make each message unique, an initialization vector must be used in the first block.

Answer : C

Hash

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

Hash functions are irreversible. This is actually required for them to fulfill their function of determining whether someone possesses an uncorrupted copy of the hashed data. This brings susceptibility to brute force attacks, which are quite powerful these days, particularly against MD5.

Answer : C

Steganography

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

Steganography is the practice of concealing a file, message, image, or video within another file, message, image, or video. The word steganography comes from Greek steganographia, which combines the words stegans , meaning 'covered or concealed', and -graphia meaning 'writing'.