100% Pass Guaranteed Free 212-81 Exam Dumps Dec 27, 2022 [Q42-Q57]

NO.42 Changes to one character in the plain text affect multiple characters in the cipher text, unlike in historical algorithms where each plain text character only affect one cipher text character.

Substitution

Avalanche

Confusion

Diffusion

Diffusion
https://en.wikipedia.org/wiki/Confusion_and_diffusion
Diffusion means that if we change a single bit of the plaintext, then (statistically) half of the bits in the ciphertext should change, and similarly, if we change one bit of the ciphertext, then approximately one half of the plaintext bits should change.[2] Since a bit can have only two states, when they are all re-evaluated and changed from one seemingly random position to another, half of the bits will have changed state.
The idea of diffusion is to hide the relationship between the ciphertext and the plain text.
This will make it hard for an attacker who tries to find out the plain text and it increases the redundancy of plain text by spreading it across the rows and columns; it is achieved through transposition of algorithm and it is used by block ciphers only.
Incorrect answers:
Confusion – Confusion means that each binary digit (bit) of the ciphertext should depend on several parts of the key, obscuring the connections between the two.
The property of confusion hides the relationship between the ciphertext and the key.
This property makes it difficult to find the key from the ciphertext and if a single bit in a key is changed, the calculation of the values of most or all of the bits in the ciphertext will be affected.
Confusion increases the ambiguity of ciphertext and it is used by both block and stream ciphers.
Avalanche – the desirable property of cryptographic algorithms, typically block ciphers and cryptographic hash functions, wherein if an input is changed slightly (for example, flipping a single bit), the output changes significantly (e.g., half the output bits flip). In the case of high-quality block ciphers, such a small change in either the key or the plaintext should cause a drastic change in the ciphertext.
Substitution – 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.

NO.43 What is the formula m^e %n related to?

Encrypting with EC

Decrypting with RSA

Generating Mersenne primes

Encrypting with RSA

NO.44 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 ______.

Mersenne’s number

Fermat’s number

Euler’s totient

Fermat’s prime

NO.45 Which service in a PKI will vouch for the identity of an individual or company?

CA

CR

KDC

CBC

NO.46 John works as a cryptography consultant. He finds that people often misunderstand the reality of breaking a cipher. What is the definition of breaking a cipher?

Finding any method that is more efficient than brute force

Uncovering the algorithm used

Rendering the cypher no longer useable

Decoding the key

NO.47 Cylinder tool. Wrap leather around to decode. The diameter is the key. Used in 7th century BC by greek poet Archilochus.

Cipher disk

Caesar cipher

Scytale

Enigma machine

NO.48 John is trying to explain the basics of cryptography to a group of young, novice, security students. Which one of the following most accurately defines encryption?

Changing a message using complex mathematics

Applying keys to a message to conceal it

Complex mathematics to conceal a message

Changing a message so it can only be easily read by the intended recipient

NO.49 Bruce Schneier is a well-known and highly respected cryptographer. He has developed several pseudo random number generators as well as worked on teams developing symmetric ciphers. Which one of the following is a symmetric block cipher designed in 1993 by Bruce Schneier team that is unpatented?

Pegasus

Blowfish

SHA1

AES

NO.50 A number that is used only one time, then discarded is called what?

IV

Nonce

Chain

Salt

NO.51 Represents the total number of possible values of keys in a cryptographic algorithm or other security measure, such as a password.

Key Schedule

Key Clustering

Key Space

Key Exchange

NO.52 A technique used to increase the security of block ciphers. It consists of steps that combine the data with portions of the key (most commonly using a simple XOR) before the first round and after the last round of encryption.

Whitening

Key Exchange

Key Schedule

Key Clustering

NO.53 What is the name of the attack where the attacker obtains the ciphertexts corresponding to a set of plaintexts of his own choosing?

Chosen plaintext

Differential cryptanalysis

Known-plaintext attack

Kasiski examination

NO.54 The greatest weakness with symmetric algorithms is _____.

They are less secure than asymmetric

The problem of key exchange

The problem of generating keys

They are slower than asymmetric

NO.55 Which of the following techniques is used (other than brute force) to attempt to derive a key?

Cryptography

Cryptoanalysis

Password cracking

Hacking

NO.56 This hash function uses 512-bit blocks and implements preset constants that change after each repetition. Each block is hashed into a 256-bit block through four branches that divides each 512 block into sixteen 32-bit words that are further encrypted and rearranged.

SHA-256

FORK-256

SHA-1

RSA

NO.57 During the process of encryption and decryption, what keys are shared?

Public keys

Public and private keys

User passwords

Private keys

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