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C839 Practice Test 2
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Preguntas del test (52)
1What type of encryption uses different keys to encrypt and decrypt the message?
- ASymmetric
- BPrivate Key
- CSecure
- DAsymmetric
2The most widely used asymmetric encryption algorithm is what?
- ARSA
- BVigenere
- CDES
- DCaesar Cipher
3Original, unencrypted information is referred to as ____.
- AText
- BPlaintext
- CCleantext
- DCiphertext
4Which of the following is NOT an asymmetric system?
- APGP
- BRSA
- CSSL
- DDES
5In order for User A to send User B an encrypted message that only User B can read, User A must encrypt message with which one of the following keys?
- AUser A's public key
- BUser A's private key
- CUser B's public key
- DUser B's private key
6The greatest weakness with symmetric algorithms is ____.
- AThey are less secure than asymmetric
- BThe problem of key exchange
- CThey are slower than asymmetric
- DThe problem of generating keys
7Which of the following is generally true about block sizes?
- ASmaller block sizes increase security
- BBlock sizes must be more than 256 bits to be secure
- CBlock size is irrelevant to security
- DLarger block sizes increase security
8A _____ is a function that takes a variable-size input, m, and returns a fixed-size string.
- ASymmetric cipher
- BHash
- CAsymmetric cipher
- DFeistel
9Which of the following is a cryptographic protocol that allows two parties to establish a shared key over an insecure channel?
- AElliptic curve
- BRSA
- CMD5
- DDiffie-Hellman
10A ____ is a digital representation of information that identifies you as a relevant entity by a trusted third party.
- ADigital Signature
- BHash
- COwnership stamp
- DDigest
11What is the standard used by most digital certificates?
- AX.509
- BCRL
- CRFC 2298
- DOCSP
12DES uses keys of what size?
- A56 bits
- B192 bits
- C128 bits
- D64 bits
13Which of the following is NOT a key sized use by AES?
- A512 bits
- B128 bits
- C192 bits
- D256 bits
14Which of the following was a multi-alphabet cipher widely used in the 16th century (1553) to the early 20th century (1900's)?
- AVigenere
- BCaesar
- CAtbash
- DScytale
15Which of the following is a substitution cipher used by ancient Hebrew scholars?
- ACaesar
- BVigenere
- CScytale
- DAtbash
16Shifting each letter in the alphabet a fixed number of spaces to the right or left is an example of what?
- ABit shifting
- BConfusion
- CMulti substitution
- DSingle substitution
17Which of the following most accurately defines encryption?
- AChanging a message so it can only be easily read by the intended recipient
- BMaking binary changes to a message to conceal it
- CChanging a message using complex mathematics
- DApplying keys to plain text
18If you use substitution alone, what weakness is present in the resulting cipher text?
- AIt is the same length as the original text
- BIt is easily broken with modern computers.
- CIt is too simple.
- DBecause it maintains letter and word frequency
19_____ uses at least two different shifts, changing the shift with different letters in the plain text.
- AAtbash
- BMulti-alphabet encryption
- CScytale
- DCaesar cipher
20____ was designed to provide built in cryptography for the clipper chip.
- ABlowfish
- BSkipjack
- CGOST
- D3DES
21Which of the following uses an 80 bit key on 64 bit blocks?
- ATwofish
- BAES
- CSkipjack
- DDES
22With _____, the message is divided into blocks and each block is encrypted separately. This is the most basic mode for symmetric encryption.
- AElectronic codebook (ECB)
- BCipher-block chaining (CBC)
- CCipher feedback (CFB)
- DOutput feedback (OFB)
23Which of the following is an example of an unbalanced Feistel?
- A3DES
- BSkipjack
- CTwofish
- DAES
24This process is done by having each block of plaintext is XORed with the previous ciphertext block before being encrypted
- AOutput feedback (OFB)
- BCipher-block chaining (CBC)
- CElectronic codebook (ECB)
- DCipher feedback (CFB)
25The process wherein the ciphertext block is encrypted then the ciphertext produced is XOR'd back with the plaintext to produce the current ciphertext block is called what?
- AOutput feedback (OFB)
- BCipher-block chaining (CBC)
- CCipher feedback (CFB)
- DElectronic codebook (ECB)
26This is a method for turning a block cipher into a stream cipher by generating a keystream block, which are then XORed with the plaintext blocks to get the ciphertext.
- ACipher feedback (CFB)
- BElectronic codebook (ECB)
- COutput feedback (OFB)
- DCipher-block chaining (CBC)
27Which of the following modes can be used to turn a block cipher into a stream cipher?
- APropagating cipher-block chaining (PCBC) and Electronic codebook (ECB)
- BCounter Mode (CTR) and Propagating cipher-block chaining (PCBC)
- CElectronic codebook (ECB) and Output feedback (OFB)
- DOutput feedback (OFB) and Counter Mode (CTR)
28A fixed-size pseudorandom number that is fed into a symmetric cipher to increase randomness is called what?
- AIV
- BKey
- CChain
- DSalt
29A number that is used only one time then discarded is called what?
- ANonce
- BChain
- CSalt
- DIV
30Which of the following is a stream cipher that uses variable length key from 1 to 256 bytes?
- ARC4
- BAES
- CDESx
- DDES
31This algorithm was published by the German 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.
- ARC4
- BBlowfish
- CFISH
- DTwofish
32Which of the following is NOT required for a hash?
- AMinimum key length of 256 bits
- BVariable-length input, fixed-length output
- CNon-reversible
- DFew collisions
33A ______ refers to a situation where two different inputs yield the same output.
- ASubstitution
- BConvergence
- CCollision
- DTransposition
34What is a salt?
- AKey rotation
- BRandom bits intermixed with a hash to increase randomness and reduce collisions.
- CRandom bits intermixed with a symmetric cipher to increase randomness and make it more secure.
- DKey whitening
35RFC 1321 describes what hash?
- ARIPEMD
- BSHA-1
- CGOST
- DMD5
36What size block does FORK256 use?
- A256
- B128
- C512
- D64
37In 1977 researchers at MIT described what asymmetric algorithm?
- ARSA
- BAES
- CDH
- DEC
38What is the formula (M^e)(%n) related to?
- AEncrypting with EC
- BGenerating Mersenne primes
- CDecrypting with RSA
- DEncrypting with RSA
39Which of the following equations is related to EC?
- AP = Cd%n
- BMe%n
- Cy2 = x3 + Ax + B
- DLet m = (p-1)(q-1)
40U.S. Patent 5,231,668 and FIPS 186 define what algorithm?
- AAES
- BRSA
- CElliptic Curve (EC)
- DDigital Signature Algorithm (DSA)
41What is X.509?
- AThe standard for PGP certificates
- BThe standard for encrypting email
- CThe standard for FIPS 186
- DThe standard for digital certificates
42What is contained in a CRL?
- AKeys for RSA
- BNew certificates
- CRevoked certificates
- DKeys for AES
43What does the Online Certificate Status Protocol (OCSP) provide?
- ARevoked certificates
- BHashing
- CVPN connectivity
- DEncryption
44In terms of cryptanalysis, what does it mean to break a cipher?
- AFinding a method to decrypt a message that is at least twice as efficient as brute force
- BTrying every possible key until you can decrypt the message
- CDeploying an algorithm that uses a 228 bit key
- DFinding any method to decrypt the message that is more efficient than brute force
45An authentication method that periodically re-authenticates the client by establishing a hash that is then resent from the client is called ______.
- APAP
- BCHAP
- CSPAP
- DEAP
46What is a TGS?
- AThe server that grants Kerberos tickets
- BProtocol for encryption
- CProtocol for key exchange
- DThe server that escrows keys
47What is Kerchoff's principle?
- AA minimum key size of 256 bits is necessary for security.
- BBoth algorithm and key should be kept secret.
- CA minimum of 15 rounds is needed for a Feistel cipher to be secure.
- DOnly the key needs to be secret, not the actual algorithm.
48Which of the following is a fundamental principle of cryptography that holds that the algorithm can be publically disclosed without damaging security?
- ABabbage's principle
- BKerkchoff's principle
- CVigenere's principle
- DShamir's principle
49A process that puts a message into the least significant bits of a binary file is called what?
- ASymmetric cryptography
- BMasking
- CSteganography
- DAsymmetric cryptography
50Which of the following is generally true about block ciphers?
- ASecret block ciphers should be trusted.
- BBlock ciphers permute the bits of the input plaintext
- CThe plaintext and ciphertext are always the same size.
- DA block cipher is an encryption function for variable-size blocks of data.
51What does the OCSP protocol provide?
- AEncryption
- BVPN connectivity
- CHashing
- DA real time protocol for verifying certificates
52A known-plaintext attack is more powerful than a ciphertext-only attack.
- AVerdadero
- BFalso
Información
- Descripción
- Test sobre C839 Practice Test 2, creado por Abigail Zorn el 11/01/2021.
- Autor
- Abigail Zorn
- Idioma
- English
- Visitas
- 2
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