WGU Course C839: Intro to Cryptography Questions and Answers 2023/2024 | Latest Update Graded A+

WGU Course C839: Intro to Cryptography Questions and Answers 2023/2024 | Latest Update Graded A+. This 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. A RC4 B Blowfish C FISH D Twofish - Answer C Which of the following is NOT required for a hash? A Minimum key length of 256 bits B Variable-length input, fixed-length output C Non-reversible D Few collisions - Answer A A ______ refers to a situation where two different inputs yield the same output. A Substitution B Convergence C Collision D Transposition - Answer 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 - Answer B RFC 1321 describes what hash? A RIPEMD B SHA1 C GOST D MD5 - Answer D What size block does FORK256 use? WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! A 256 B 128 C 512 D 64 - Answer C In 1977 researchers at MIT described what asymmetric algorithm? A RSA B AES C DH D EC - Answer A What is the formula (M^e)(%n) related to? A Encrypting with EC B Generating Mersenne primes C Decrypting with RSA D Encrypting with RSA - Answer C Which of the following equations is related to EC? A P = Cd%n B Me%n C y2 = x3 + Ax + B D Let m = (p-1)(q-1) - Answer C U.S. Patent 5,231,668 and FIPS 186 define what algorithm? A AES B RSA C Elliptic Curve (EC) D Digital Signature Algorithm (DSA) - Answer 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 - Answer D What is contained in a CRL? A Keys for RSA B New certificates C Revoked certificates D Keys for AES - Answer C WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! What does the Online Certificate Status Protocol (OCSP) provide? A Revoked certificates B Hashing C VPN connectivity D Encryption - Answer 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 message that is more efficient than brute force - Answer D An authentication method that periodically re-authenticates the client by establishing a hash that is then resent from the client is called ______. A PAP B CHAP C SPAP D EAP - Answer B What is a TGS? A The server that grants Kerberos tickets B protocol for encryption C protocol for key exchange D The server that escrows keys - Answer A What is Kerchoff's principle? 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. - Answer D 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 WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! B Kerkchoff's principle C Vigenere's principle D Shamir's principle - Answer 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 - Answer C If you wished to see a list of revoked certificates from a CA, where would you look? A CRL B CA C RFC D RA - Answer A Which of the following is generally true about block 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. - Answer C What does the OCSP protocol provide? A encryption B VPN connectivity C hashing D a real time protocol for verifying certificates - Answer D U.S. encryption standard that replaced DES. Block symmetric cipher that uses 128- bit block sizes and various key lengths (128, 192, 256). - Answer AES DES, 3DES, SHA, AES (some AES implementations are Type I) - Answer Class 3 Algorithms Encryption method where the sender and receiver use an instance of the same key for encryption and decryption purposes. - Answer Symmetric Block symmetric algorithm chosen by NIST as an encryption standard in 1976. It uses a 56-bit true key bit size, 64-bit block size, and 16 rounds of computation. - Answer Data Encryption Standard (DES) WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! technical specification indicating how multimedia data and e-mail binary attachments are to be transferred. - Answer Multipurpose Internet Mail Extensions (MIME) Valid data transmission is maliciously or fraudulently repeated to allow an entity gain unauthorized access. - Answer Replay Attack protocol suite provides a method of setting up a secure channel for protected data exchange between two devices. - Answer Internet Protocol Security (IPSec) Juniper (block cipher) MAYFLY (asymmetric) FASTHASH (hashing) WALBURN (high bandwith link encryption) PEGASUS (satellite telemetry) - Answer Class 1 Algorithms Component of a PKI that creates and maintains digital certificates throughout their life cycles. - Answer Certificate Authority Uses public key encryption and provides data encryption, server authentication, message integrity, and optional client authentication. It is currently at version 3.0. - Answer Secure Sockets Layer (SSL) Manipulating individuals so that they will divulge confidential information, rather than by breaking in or using technical cracking techniques. - Answer Social engineering attack Cryptanalysis attack where the attacker is assumed to have access only to a set of ciphertexts. - Answer Ciphertext-only attack servers and software signing, for which independent verification and checking of identity and authority is done by issuing CA - Answer Class 3 Certificates it should be impossible for any attacker to calculate, or otherwise guess, from any given subsequence, any previous or future values in the sequence - Answer BSI Criteria K3 states Cryptanalysis attack that uses identified statistical patterns. - Answer Statistical attack organizations for which proof of identity is required - Answer Class 2 Certificates Block symmetric cipher that uses a 128-bit key and 64-bit block size. - Answer International Data Encryption Algorithm (IDEA) individuals, and intended for email - Answer Class 1 Certificates WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! A form of cryptanalysis applicable to symmetric key 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. - Answer Differential cryptanalysis Cryptanalysis attack where the attacker is assumed to have access to sets of corresponding plaintext and ciphertext. - Answer Known plaintext attack Carries out real-time validation of a certificate and reports back to the user whether the certificate is valid, invalid, or unknown. OCSP checks the CRL that is maintained by the CA. - Answer Online Certificate Status Protocol (OCSP) What is the formula Me%n related to? - Answer Encrypting with RSA Plain-text is equal to the encryption function (E) with the key (k) and the ciphertext (c) being passed as parameters to that function - Answer P= E(k,c) Symmetric decryption Not certified for government use - Answer Class 4 algorithms 64 bit algorithm operating at 56 bits with an 8 bit parity block - Answer DES AH is the authenticating protocol, and ESP is an authenticating and encrypting protocol that uses cryptographic mechanisms to provide source authentication, confidentiality, and message integrity. - Answer Authentication Header (AH) and Encapsulating Security Payload (ESP). developed as a Russian national standard and produced fixed length outputs of 256 bits - Answer GOST A measure of the uncertainty associated with a random variable - Answer Entropy Attempts to make the statistical frequencies of the ciphertext and actual key as complex as possible - Answer Confusion Like AES, Serpent has a block size of 128 bits and 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-bit S-boxes 32 times in parallel. Designed by Ross Anderson, Eli Biham, and Lars Knudsen. - Answer Serpent What is the difference between Secure HTTP (SHTTP) and HTTP Secure (HTTPS)? - Answer S-HTTP is a technology that protects each message sent between two WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! computers, while HTTPS protects the communication channel between two computers, messages and all. Which of the following was a multi alphabet cipher widely used from the 16th century to the early 20th century? - Answer Vigenere A _____ is a function that takes a variable-size input m and returns a fixed-size string. - Answer Hash A small change that yields large effects in the output. - Answer Avalanche Private organizations or governmental security - Answer Class 5 Certificates Numbers that have no factors in common with another. - Answer Co-prime numbers Cryptanalysis attack that exploits vulnerabilities within the intrinsic algebraic structure of mathematical functions. - Answer Algebraic attack Designed by Ross Anderson and Eli Biham in 1995. The size of a ________ hash value is 192 bits. - Answer TIGER 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? - Answer User B's public key Public key algorithm that can be used for digital signatures, encryption, and key exchange. an extension of the Diffie-Hellman algorithm. - Answer El Gamal Block symmetric cipher that was chosen to fulfill the Advanced Encryption Standard. It uses a 128-bit block size and various key lengths (128, 192, 256). - Answer Rijndael Published by Siemens in 1993. A software-based stream cipher using a Lagged Fibonacci generator (pseudorandom number generator). - Answer FISH 128 bit hash. RFC 1321 - Answer MD5 Cipher text (C) is equal to the encryption function (E) with the key (k) and plain-text (p) being passed as parameters to that function - Answer C = E(k,p) Symmetric encryption It is impossible to compress the data such that the code is less than the Shannon entropy of the source, without it being virtually certain that information will be lost - Answer Shannon's source coding theorem WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! A non-secret binary vector used as the initializing input algorithm for the encryption of a plaintext block sequence to increase security by introducing additional cryptographic variance. - Answer IV (Initialization Vector) If a cryptanalysis uncovers a method that can derive a key for an algorithm, but is only slightly faster than brute force, what is this called? - Answer Success • Confidentiality • Access control • Integrity • Authentication • Nonrepudiation - Answer PKI services It should be impossible for any attacker to calculate, or guess from an inner state of the generator, any previous numbers in the sequence or any previous inner generator states - Answer BSI criteria K4 states: Developed by the NSA for use in the clipper chip. Skipjack uses an 80-bit key to encrypt or decrypt 64-bit data blocks. It is an unbalanced Feistel network with 32 rounds. - Answer Skipjack Algorithm that was chosen for the Data Encryption Standard, which was altered and renamed Data Encryption Algorithm. - Answer Lucifer Announced by NIST as FIPS 197. Has 3 key sizes: 128, 192, 256 and all operate on 128 bit block - Answer AES Symmetric cipher that applies DES three times to each block of data during the encryption process. - Answer Triple DES (3DES) Attack that uses information (timing, power consumption) that has been gathered to uncover sensitive data or processing functions. - Answer Side-channel attack A 160 bit hash with 3 other versions: RIPEMD-128 (128 bit), RIPEMD-256 (256 bit), RIPEMD-320 (320 bit) - Answer RIPEMD-160 Transposition processes used in encryption functions to increase randomness. - Answer Diffusion Used to store, distribute, and maintain cryptographic session and secret keys. - Answer Key Distribution Center (KDC) WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! Designed by Phil Zimmerman as a freeware e-mail security program and was released in 1991. It was the first widespread public key encryption program. - Answer Pretty Good Privacy (PGP) A number that is used only one time then discarded is called what? - Answer Nonce Improvement on FISH due to vulnerability to known-plaintext attacks. Published by Ross Anderson. - Answer PIKE Stands for Menezes-Qu-Vanstone and is a protocol used for key agreement that is based on DH. Incorporated in public key standard IEEE P1363 - Answer MQV A cryptographic protocol and infrastructure developed to send encrypted credit card numbers over the Internet. - Answer Secure Electronic Transaction (SET) The algorithm is used identically for encryption and decryption as the data stream is simply XORed with the key. RC4 uses a variable-length key from 1 to 2048 bits, (minimum of 40 bits or higher to be considered secure). That key constitutes a state table that is used for the subsequent generation of pseudo-random bytes and then to generate - Answer RC4 The payload and the routing and header information are protected in this mode. - Answer Tunnel mode Values that are used with algorithms to increase randomness for cryptographic functions. - Answer Initialization vectors (IVs) Ticket granting service - Answer TGS This is a variation of DES that XORs another 64-bit key to the plaintext before applying the DES algorithm. The concept of simply XORing in an additional key is called whitening. This adds to the confusion of the resultant text. - Answer DESx The total number of co prime numbers for a number n - Answer Euler's Totient Naor-Reingold, Mersenne Twister, Linear Congruential Generator,