C839 Additional Practice Answers 1 for PDF

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Just to process time by running a hot dog stand in new york city beaches.
Having mustard is the best part of the stand...

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Answer Key 1.

What term from the list below best describes a data concealment method for covert communication that makes use of LSB replacement? Cryptanalysis Steganalysis Steganography Whitening

2.

Which block cipher below uses a block size of 128 bits and key sizes up to 256 bits? DES Blowfish Twofish Tiger

3.

Symmetric encryption is expressed mathematically as: C = E(k,p) P = E(k,c) Me % n y2 = x3 + Ax + B

4.

Hash Value Matching. Bit sizes may be used once, multiple times, or not at all. Hash Name 1. TIGER 2. SHA256 3. FORK256 4. SHA1 5. GOST 6. MD5 7. RIPEMD-160

5.

1. 2. 3. 4. 5. 6. 7.

7.

8.

Choice A. B. C. D. E. F. G.

16 bit 32 bit 64 bit 128 bit 160 bit 192 bit 256 bit

Symmetric Block Cipher to Key and Block Size Matching. Attributes may be used once, multiple times or not at all. Cipher Name

6.

Matched Answer _F___ _G___ _G___ _E___ _G___ _D___ _E___

Matched Answer

AES IDEA DES Blowfish Twofish Skipjack Serpent

_E___ _D___ _A___ _B___ _F___ _C___ _E___

Attribute A. B. C. D. E.

64 bit blocks; 56 bit key 64 bit blocks; 32-448 bit key 64 bit blocks; 80 bit key 64 bit blocks; 128 bit key 128 bit blocks; 128, 192 or 256 bit key F. 128 bit blocks; 1-256 bit key G. 26 bit blocks; 64 bit key

Identify and select the asymmetric encryption algorithms from the list below. (Select 3). RSA

IDEA

MD5

AES

ECC

DSA

RIPEMD-160

OFB

Identify and select the symmetric stream ciphers from the list below. (Select 3). DES

ECC

Blowfish

GOST

FISH

PIKE

RC4

AES

Identify and select the hash algorithms from the list below. (Select 4). AES

MD5

DH

GOST

FORK256

PIKE

RC4

RIPEMD-160

9.

Identify and select three viable options for key exchange from the list below. RSA

DH

MD5

AES

ECDH

SHA256

RIPEMD-160

MQV

10. Identify and select the 32-round symmetric block ciphers from the list below. (Select two. RSA

DH

DSA

AES

Skipjack

Blowfish

Serpent

DES

11. Which asymmetric encryption algorithm leverages characteristics of prime numbers and utilizes variable key lengths (1024-4096)? DSA ECC RSA Serpent 12. Which equation below represents the encryption process for RSA? C = E(k,p) P = E(k,c) Me % n y2 = x3 + Ax + B 13. How many rounds are used in AES encryption? 8, 10, or 12 10, 12, or 14 32 16 14. Of the two processes used in symmetric key cryptography, which involves XORing the plaintext message with the key? Transposition

Clustering

Initialization

Substitution

15. Of the two processes used in symmetric key cryptography, which involves swapping blocks of the text? Transposition

Clustering

Initialization

Substitution

16. An instance where two different pieces of data are hashed separately, but both result in a single identical hash value is described by what term? Collision Clustering Evolution Polybius 17. An instance where different encryption keys generate the same ciphertext from the same plaintext message is described by what term? Columnar rotation Columnar substitution Collision Clustering 18. Symmetric decryption is expressed mathematically as: C = E(k,p) P = E(k,c) Me % n y2 = x3 + Ax + B? 19. Instances where a change in in one bit in the plaintext would affect all the bits of the ciphertext is best described by what term? Avalanche Diffusion 20. Instances where a change in in one bit in the plaintext would affect multiple characters in the ciphertext is best described by what term? Confusion Diffusion

21. What is the standard for digital certificates? RFC 3526 DSA FIPS 197 X.509

22. If timeliness is a priority factor for checking revocation status, which option from the list below would you prefer and why? CRL, because it facilitates verifying certificates in real time OCSP, because it facilitates verifying certificates in real time 23. When looking for an encryption scheme where speed is of utmost importance, which would you prefer from the list below? Symmetric Asymmetric 24. When looking for an encryption solution for the data on your computer where full disk encryption is of utmost importance, which would you select from the list below? Bitlocker EFS 25. What Federal Information Processing Standard pertains to DSA? FIPS 197 FIPS 196 FIPS 180-4 FIPS 179 26. What Federal Information Processing Standard pertains to AES? FIPS 197 FIPS 196 FIPS 180-4 FIPS 179

27. From the list below, which two symmetric block encryption modes turn block ciphers into stream ciphers? OFB CTR ECB RC4 28. With which encryption type would you mostly likely need an accompanying key exchange solution for? Asymmetric Symmetric

29. What term from the list below best represents “one-way” encryption i.e. not reversible? Salt Symmetric DES Hash 30. Which equation below is associated with Elliptic Curve? C = E(k,p) P = E(k,c) Me % n y2 = x3 + Ax + B 31. From the terms below, which are associated with encryption using two keys? (Select 3) Asymmetric

SHA-2

Symmetric

AES

DES

DSA

RSA

Twofish

32. If you are sending an encrypted message to a colleague using symmetric encryption, of the choices below, (1) which key would you use to encrypt the message, and (2) which key would your colleague use to decrypt the message? (1) your colleague’s public key, (2) your colleague’s private key (1) your public key, (2) your private key (1) your private key, (2) your private key (1) your colleague’s private key, (2) your public key

33. If you are sending an encrypted message to a colleague using asymmetric encryption, of the choices below, (1) which key would you use to encrypt the message, and (2) which key would your colleague use to decrypt the message? (1) your colleague’s public key, (2) your colleague’s private key (1) your public key, (2) your private key (1) your private key, (2) your private key (1) your colleague’s private key, (2) your public key

34. From the list below, what term best describes an arbitrary, random or pseudo-random number used only once in cryptographic communication and is then discarded? Key Algorithm Round Nonce 35. What term below best describes an attack in which the attacker only has access to the ciphertext of a message? Chosen ciphertext Ciphertext only Known plaintext Plaintext only 36. According to Kerchoff’s Principle, a cryptosystem will remain secure so long as which component of it is not publicly known? Key Decryption Algorithm Ciphertext Encryption Algorithm

37. What technique should be used in conjunction with substitution to break up letter/word frequency and aid in combatting frequency analysis attacks? Decoding Hashing Signing Transposition

38. What trusted entity associated with certificate management is responsible for issuing, revoking, and managing digital certificates? Certification Authority Registration Authority Certificate Authority Key Distribution Center 39. What symmetric cipher was developed for use in the clipper chip? Skipjack Twofish Blowfish DSA 40. Which term from the list below best describes a number that only shares the number 1 as a common factor with another? Prime Co-Prime Rational Reciprocal 41. What is the binary XOR result the following number sets 10011011 & 11111110? 10011010 01100101 11111111 00000000 42. The Feistel Network used in symmetric block encryption entails the splitting of a block of plaintext prior to the application of respective encryption round and XOR functions. Which cipher from the list below is an “unbalanced” Feistel cipher (i.e. blocks of plaintext are split into unequal parts)? RC4 Skipjack PIKE TIGER

43. From the list below, which term is best described as a fixed-size, random stream, that is added to a block cipher to increase randomness? Feistel Initialization Vector Session Key Induction Vector

44. From the list below, which term is best described as random bits added to a password hash to help with safeguarding passwords in storage? Nonce

IV

Salt

Rounds

45. The Advanced Encryption Standard is a subset of which algorithm? Lucifer Kasiski Fibonacci Rijndael 46. Which software-based stream cipher uses a lagged Fibonacci generator? GOST FISH Blowfish Twofish 47. Which of the following is true of hash encryption? Requires a fixed length input and produces a different fixed length output Requires a fixed length input and produces a variable length output Accepts a variable length input and produces a fixed length output Accepts a variable length input and produces a different variable length output 48. What are the two types of symmetric encryption? Block Strong Fixed Stream

49. Which WiFI encryption standard is based on 802.11i and uses AES with CCMP to provide for enhanced confidentiality, integrity and authentication? WPA WEP WPA-2 Bluetooth

50. What is the binary OR result the following number sets 10011011 & 11111110? 10011010 01100101 11111111 00000000 51. What type of cryptanalysis involves the examination of differences in an input and how that affects the resultant difference in output? Hypothesis cryptanalysis Linear cryptanalysis Pseudo-random cryptanalysis Differential cryptanalysis 52. Identify and select the mono-alphabetic ciphers from the list below. (Select 4) Vigenere

ENIGMA

Atbash

Disk cipher

Ceasar

ROT-13

Scytale

ADFGVX

53. Which cipher entails using a rod of a certain length to create/encrypt a message, and the requiring the message recipient to use an identical sized rod to read/decrypt the message? Scytale Atbash Playfair PIKE

54. Which cipher makes use of a 5x5 table containing a keyword or key phrase and encrypts pairs of letters or digraphs? Scytale

Caesar

Playfair

Atbash

55. Which term from the list below represents the entire cryptographic operation i.e. the algorithm, key, and key management functions? Cryptography Cryptanalysis Cryptology Cryptosystem 56. Which term from the list below represents the total number of possible values of keys in a cryptographic algorithm or other security measure? Key negotiation Key space Cryptovariable Initialization vector 57. What term from the list below best describes a number whose factors are 1 and itself? Prime Co-Prime Rational Pseudo-random 58. From the list below, what term describes a mechanism used to create number streams with random properties? Examples include Lagged Fibonacci and Mersenne Twister. Modulus Operator Hash Algorithm Crypto randomizer Pseudo-random number generator

59. Kerberos components matching Hash Name Matched Answer 1. Ticket _B___ 2. TGS _D___ 3. KDC _A___ 4. TGT _E___ 5. AS _C___ Choices A. Server that provides the initial ticket B. Used to authenticate. Contains the identity of the client, the session key, timestamp, and checksum C. Server that authorizes the principal and connects them to the ticket granting server D. Issues tickets E. The ticket that is granted during the authentication process 60. Wifi attribute matching Hash Name 1. WEP 2. WPA 3. WPA-2 4. WPA-2 Enterprise

Choices A. B. C. D.

Matched Answer _C___ _B___ _A___ _D___

802.11i, uses AES with CCMP Replaces RC4 with TKIP Uses RC4, employs a 40-bit key with a 24-bit IV WPA-802.1x, requires RADUIS, employs EAP for authentication

61. What term below best describes an attack in which the attacker obtains ciphertext corresponding to a set of plaintexts to use in an attempt to derive the key used? Chosen plaintext Ciphertext only Known plaintext Plaintext only...