WGU Course C839 - Intro to Cryptography Quizlet by Brian Mac Farlane Flashcards Quizlet PDF

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10/5/21, 6:06 PM

WGU Course C839 - Intro to Cryptography Quizlet by Brian MacFarlane Flashcards | Quizlet

Science / Computer Science / Computer Security and Reliability

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Terms in this set (293) What type of encryption uses different keys to

D

encrypt and decrypt the message? A Symmetric B Private key C Secure D Asymmetric

The most widely used asymmetric encryption

A

algorithm is what? A RSA B Vigenere C DES D Caesar Cipher

Original, unencrypted information is referred to as

B

____. A text B plaintext C cleantext D ciphertext

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Which of the following is NOT an asymmetric

D

system? A PGP B RSA C SSL D DES

In order for User A to send User B an encrypted

C

message that only User B can read, User A must encrypt message with which of the following keys? A User A's public key B User A's private key C User B's public key D User B's private key

The greatest weakness with symmetric algorithms is

B

_____. A They are less secure than asymmetric B The problem of key exchange C They are slower than asymmetric D The problem of generating keys

Which of the following is generally true about block

D

sizes? A Smaller block sizes increase security B Block sizes must be more than 256 bits to be secure C Block size is irrelevant to security D Larger block sizes increase security

A _____ is a function that takes a variable-size input m

B

and returns a fixed-size string. A Symmetric cipher B Hash C Asymmetric cipher D Feistel

Which of the following is a cryptographic protocol

D

that allows two parties to establish a shared key over an insecure channel? A Elliptic Curve B RSA C MD5 D Diffie-Hellman

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A _________ is a digital representation of information

A

that identifies you as a relevant entity by a trusted third party? A Digital Signature B Hash C Ownership stamp D Digest

What is the standard used by most digital

A

certificates? A X.509 B CRL C RFC 2298 D OCSP

DES uses keys of what size?

A

A 56 bits B 192 bits C 128 bits D 64 bits

Which of the following is NOT a key size used by

A

AES? A 512 bits B 128 bits C 192 bits D 256 bits

Which of the following was a multi alphabet cipher

A

widely used from the 16th century (1553) to the early 20th century (1900s)? A Vigenere B Caesar C Atbash D Scytale

Which of the following is a substitution cipher used

D

by ancient Hebrew scholars? A Caesar B Vigenere C Scytale D Atbash

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Shifting each letter in the alphabet a fixed number

D

of spaces to the right or left is an example of what? A Bit shifting B Confusion C Multi substitution D Single substitution

Which of the following most accurately defines

A

encryption? A changing a message so it can only be easily read by the intended recipient B Making binary changes to a message to conceal it C changing a message using complex mathematics D Applying keys to plain text

If you use substitution alone, what weakness is

D

present in the resulting cipher text? A It is the same length as the original text B It is easily broken with modern computers. C It is too simple. D Because it maintains letter and word frequency.

_____ uses at least two different shifts, changing the

B

shift with different letters in the plain text. A Atbash B multi-alphabet encryption C Scytale D Caesar cipher

____ was designed to provide built in cryptography

B

for the clipper chip. A Blowfish B Skipjack C GOST D 3DES

Which of the following uses an 80 bit key on 64 bit

C

blocks? A Twofish B AES C Skipjack D DES

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With _____, the message is divided into blocks and

A

each block is encrypted separately. This is the most basic mode for symmetric encryption. A Electronic codebook (ECB) B Cipher-block chaining (CBC) C Cipher feedback (CFB) D Output feedback (OFB)

Which of the following is an example of an

B

unbalanced Feistel? A 3DES B Skipjack C Twofish D AES

This process is done by having each block of

B

plaintext is XORed with the previous ciphertext block before being encrypted. A Output feedback (OFB) B Cipher-block chaining (CBC) C Electronic codebook (ECB) D Cipher feedback (CFB)

The process wherein the ciphertext block is

C

encrypted then the ciphertext produced is XOR'd back with the plaintext to produce the current ciphertext block is called what? A Output feedback (OFB) B Cipher-block chaining (CBC) C Cipher feedback (CFB) D Electronic codebook (ECB)

This is a method for turning a block cipher into a

C

stream cipher by generating a keystream block, which are then XORed with the plaintext blocks to get the ciphertext. A Cipher feedback (CFB) B Electronic codebook (ECB) C Output feedback (OFB) D Cipher-block chaining (CBC)

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Which of the following modes can be used to turn a

D

block cipher into a stream cipher? A Propagating cipher-block chaining (PCBC) and Electronic codebook (ECB) B Counter Mode (CTR) and Propagating cipherblock chaining (PCBC) C Electronic codebook (ECB) and Output feedback (OFB) D Output feedback (OFB) and Counter Mode (CTR)

A fixed-size pseudorandom number that is fed into

A

a symmetric cipher to increase randomness is called what? A IV B Key C Chain D Salt

A number that is used only one time then discarded

A

is called what? A Nonce B Chain C Salt D IV

Which of the following is a stream cipher that uses

A

variable length key from 1 to 256 bytes? A RC4 B AES C DESx D DES

This algorithm was published by the German

C

engineering firm Seimans in 1993. It is a software based stream cipher using Lagged Fibonacci generator along with a concept borrowed from the shrinking generator ciphers. A RC4 B Blowfish C FISH D Twofish

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Which of the following is NOT required for a hash?

A

A Minimum key length of 256 bits B Variable-length input, fixed-length output C Non-reversible D Few collisions

A ______ refers to a situation where two different

C

inputs yield the same output. A Substitution B Convergence C Collision D Transposition

What is a salt?

B

A Key rotation B Random bits intermixed with a hash to increase randomness and reduce collisions. C Random bits intermixed with a symmetric cipher to increase randomness and make it more secure. D Key whitening

RFC 1321 describes what hash?

D

A RIPEMD B SHA1 C GOST D MD5

What size block does FORK256 use?

C

A 256 B 128 C 512 D 64

In 1977 researchers at MIT described what

A

asymmetric algorithm? A RSA B AES C DH D EC

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What is the formula (M^e)(%n) related to?

C

A Encrypting with EC B Generating Mersenne primes C Decrypting with RSA D Encrypting with RSA

Which of the following equations is related to EC?

C

A P = Cd%n B Me%n C y2 = x3 + Ax + B D Let m = (p-1)(q-1)

U.S. Patent 5,231,668 and FIPS 186 define what

D

algorithm? A AES B RSA C Elliptic Curve (EC) D Digital Signature Algorithm (DSA)

What is X.509?

D

A The standard for PGP certificates B The standard for encrypting email C The standard for FIPS 186 D The standard for digital certificates

What is contained in a CRL?

C

A Keys for RSA B New certificates C Revoked certificates D Keys for AES

What does the Online Certificate Status Protocol

A

(OCSP) provide? A Revoked certificates B Hashing C VPN connectivity D Encryption

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In terms of cryptanalysis, what does it mean to

D

break a cipher? A finding a method to decrypt a message that is at least twice as efficient as brute force B trying every possible key until you can decrypt the message C deploying an algorithm that uses a 228 bit key D finding any method to decrypt the message that is more efficient than brute force

An authentication method that periodically re-

B

authenticates the client by establishing a hash that is then resent from the client is called ______. A PAP B CHAP C SPAP D EAP

What is a TGS?

A

A The server that grants Kerberos tickets B protocol for encryption C protocol for key exchange D The server that escrows keys

What is Kerchoff's principle?

D

A A minimum key size of 256 bits is necessary for security. B Both algorithm and key should be kept secret. C A minimum of 15 rounds is needed for a Feistel cipher to be secure. D Only the key needs to be secret, not the actual algorithm.

Which of the following is a fundamental principle of

B

cryptography that holds that the algorithm can be publically disclosed without damaging security? A Babbage's principle B Kerkchoff's principle C Vigenere's principle D Shamir's principle

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A process that puts a message into the least

C

significant bits of a binary file is called what? A Symmetric cryptography B Masking C Steganography D Asymmetric cryptography

If you wished to see a list of revoked certificates

A

from a CA, where would you look? A CRL B CA C RFC D RA

Which of the following is generally true about block

C

ciphers? A Secret block ciphers should be trusted. B Block ciphers permute the bits of the input plaintext. C The plaintext and ciphertext are always the same size. D A block cipher is an encryption function for variable-size blocks of data.

What does the OCSP protocol provide?

D

A encryption B VPN connectivity C hashing D a real time protocol for verifying certificates

U.S. encryption standard that replaced DES. Block

AES

symmetric cipher that uses 128-bit block sizes and various key lengths (128, 192, 256).

DES, 3DES, SHA, AES (some AES implementations

Class 3 Algorithms

are Type I)

Encryption method where the sender and receiver

Symmetric

use an instance of the same key for encryption and decryption purposes.

Block symmetric algorithm chosen by NIST as an

Data Encryption Standard (DES)

encryption standard in 1976. It uses a 56-bit true key bit size, 64-bit block size, and 16 rounds of computation.

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technical specification indicating how multimedia

Multipurpose Internet Mail Extensions (MIME)

data and e-mail binary attachments are to be transferred.

Valid data transmission is maliciously or fraudulently

Replay Attack

repeated to allow an entity gain unauthorized access.

protocol suite provides a method of setting up a

Internet Protocol Security (IPSec)

secure channel for protected data exchange between two devices.

Juniper (block cipher)

Class 1 Algorithms

MAYFLY (asymmetric) FASTHASH (hashing) WALBURN (high bandwith link encryption) PEGASUS (satellite telemetry)

Component of a PKI that creates and maintains

Certificate Authority

digital certificates throughout their life cycles.

Uses public key encryption and provides data

Secure Sockets Layer (SSL)

encryption, server authentication, message integrity, and optional client authentication. It is currently at version 3.0.

Manipulating individuals so that they will divulge

Social engineering attack

confidential information, rather than by breaking in or using technical cracking techniques.

Cryptanalysis attack where the attacker is assumed

Ciphertext-only attack

to have access only to a set of ciphertexts.

servers and software signing, for which

Class 3 Certificates

independent verification and checking of identity and authority is done by issuing CA

it should be impossible for any attacker to

BSI Criteria K3 states

calculate, or otherwise guess, from any given subsequence, any previous or future values in the sequence

Cryptanalysis attack that uses identified statistical

Statistical attack

patterns.

organizations for which proof of identity is required

Class 2 Certificates

Block symmetric cipher that uses a 128-bit key and

International Data Encryption Algorithm (IDEA)

64-bit block size.

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individuals, and intended for email

A form of cryptanalysis applicable to symmetric key

Class 1 Certificates

Differential cryptanalysis

algorithms that was invented by Eli Biham and Adi Shamir. The examination of differences in an input and how that affects the resultant difference in the output.

Cryptanalysis attack where the attacker is assumed

Known plaintext attack

to have access to sets of corresponding plaintext and ciphertext.

Carries out real-time validation of a certificate and

Online Certificate Status Protocol (OCSP)

reports back to the user whether the certificate is valid, invalid, or unknown. OCSP checks the CRL that is maintained by the CA.

What is the formula Me%n related to?

Plain-text is equal to the encryption function (E)

Encrypting with RSA

P= E(k,c) Symmetric decryption

with the key (k) and the ciphertext (c) being passed as parameters to that function

Not certified for government use

64 bit algorithm operating at 56 bits with an 8 bit

Class 4 algorithms

DES

parity block

AH is the authenticating protocol, and ESP is an

Authentication Header (AH) and Encapsulating Security Payload (ESP).

authenticating and encrypting protocol that uses cryptographic mechanisms to provide source authentication, confidentiality, and message integrity.

developed as a Russian national standard and

GOST

produced fixed length outputs of 256 bits

A measure of the uncertainty associated with a

Entropy

random variable

Attempts to make the statistical frequencies of the

Confusion

ciphertext and actual key as complex as possible

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Like AES, Serpent has a block size of 128 bits and

Serpent

can have a key size of 128, 192, or 256 bits. The algorithm is also a substitution-permutation network like AES. It uses 32 rounds working with a block of four 32-bit words. Each round applies one of eight 4-bit to 4-bi...