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Cryptography Questions With Answers C839/cryptography1.docs Mode 1.What type of encryption uses different keys to encrypt and decrypt the message? A Symme tric B Private key C Secure D Asymmetric D The most widely used asymmetric encryption algorithm is what? A RSA B Vigen ere C DES D Caesar Cipher A 2.Original, unencrypted information is referred to as
. A text B plaint ext C cleant ext D ciphertext B Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers B RS A C SS L D DES D 3.In order for User A to send User B an encrypted 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 C 4.The greatest weakness with symmetric algorithms is
. 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 B Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers 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 D 6.A is a function that takes a variable-size input m and returns a fixed- size string. A Symmetric cipher B Hash C Asymmetric cipher D Feistel B 7.Which of the following is a cryptographic protocol that allows two parties to establish a shared key over an insecure channel? A Elliptic Curve B RSA C MD D Diffie-Hellman D 8.A is a digital representation of information that identifies you as a relevant entity by a trusted third party? A Digital Signature Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers B Hash C Ownership stamp D Digest A 9.What is the standard used by most digital certificates? A X. B CRL C RFC 2298 D OCSP A 10.DES uses keys of what size? A 56 bits B 192 bits C 128 bits D 64 bits A 11.Which of the following is NOT a key size used by AES? A 512 bits B 128 bits C 192 bits D 256 bits A 12.Which of the following was a multi Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers ion C Multi substitution D Single substitution D 15.Which of the following most accurately defines 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 A If you use substitution alone, what weakness is 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. D Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers uses at least two different shifts, changing the shift with different letters in the plain text. A Atbash B multi-alphabet encryption C Scytale D Caesar cipher B was designed to provide built in cryptography for the clipper chip. A Blowfish B Skipj ack C GOST D 3DES B Which of the following uses an 80 bit key on 64 bit blocks? A Twofish B AES C Skipjack D DES C With , the message is divided into blocks and each block is encrypted separately. This is the most basic mode for symmetric encryption. A Electronic codebook (ECB) B Cipher-block Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers 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) C This 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. A Cipher feedback (CFB) B Electronic codebook (ECB) C Output feedback (OFB) D Cipher-block chaining (CBC) C Which of the following modes can be used to turn a block cipher into a stream cipher? A Propagating cipher-block chaining (PCBC) and Electronic codebook (ECB) B Counter Mode (CTR) and Propagating cipher-block chaining (PCBC) Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers C Electronic codebook (ECB) and Output feedback (OFB) D Output feedback (OFB) and Counter Mode (CTR) D A fixed-size pseudorandom number that is fed into a symmetric cipher to increase randomness is called what? A IV B Key C Chain D Salt A A number that is used only one time then discarded is called what? A Nonce B Chai n C Salt D IV A Which of the following is a stream cipher that uses variable length key from 1 to 256 bytes? Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers A refers to a situation where two different inputs yield the same output. A Substitu tion B Converg ence C Collision D Transpositi on C What is a salt? 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 B RFC 1321 Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers describes what hash? A RIPEMD B SHA 1 C GOS T Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers U.S. Patent 5,231,668 and FIPS 186 define what algorithm? A AE S B RS A C Elliptic Curve (EC) D Digital Signature Algorithm (DSA) D What is X.509? A The standard for PGP certificates B The standard for encrypting email C The standard for FIPS 186 D The standard for digital certificates D What is contained in a CRL? Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers A Keys for RSA B New certificates C Revoked certificates D Keys for AES C What does the Online Certificate Status Protocol (OCSP) provide? A Revoked certificates B Hashing C VPN connectivit y D Encryption A In terms of cryptanalysis, what does it mean to 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 Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers 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. D Western Governors University>INFORMATIO C839/C
Cryptography Questions With Answers Which of the following is a fundamental principle of 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 B A process that puts a message into the least significant bits of a binary file is called what? A Symmetric cryptography B Masking C Steganography D Asymmetric cryptography C If you wished to see a list of revoked certificates from a CA, where would you look? A CR L B CA C RF C D RA A Western Governors University>INFORMATIO C839/C
