WGU Course C839 Intro to Cryptography; Questions With Correct Answers | Latest Update Graded A+ (2023/2024)

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, Lehmer Random Number Generator (twisted generalized feedback shift registers), Lagged Fibonacci Generator (LFG) - Answer Examples of PRNGs (pseudo random number generators) WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! Skipjack, Key Exchange Algorithm (KEA) - Answer Class 2 Algorithms Responsible for the accuracy of the information contained in a certificate request. The _______________ is a proxy for the CA and also expected to perform user validation before issuing a certificate request. - Answer Registration authority (RA) HTTP running over SSL. - Answer HTTP Secure (HTTPS) Component that keeps track of the different SAs and tells the device which one is appropriate to invoke for the different packets it receives. - Answer security parameter index (SPI) Which encryption standard is used primarily for mobile devices? - Answer ECC Stream symmetric cipher that was created by Ron Rivest of RSA. Used in SSL and WEP. - Answer RC4 256 bit and 512 bit hash - Answer SHA-2 Microchip installed on the motherboard of modern computers and is dedicated to carrying out security functions that involve the storage and processing of symmetric and asymmetric keys, hashes, and digital certificates. - Answer Trusted Platform Module (TPM) Cryptographic hash function that uses a symmetric key value and is used for data integrity and data origin authentication. - Answer Hashed message authentication code (HMAC) Type of tunneling mechanism that provides terminal-like access to remote computers. Provides authentication and secure transmission over vulnerable channels like the Internet. - Answer Secure Shell (SSH) Is an authentication key agreement cryptography function very similar to DiffieHellman. - Answer MQV (Menezes-Qu-Vanstone) Provide authentication of a sender and integrity of a sender's message. A message is input into a hash function. Then the hash value is encrypted using the private key of the sender. The result of these two steps yields a __________________. - Answer Digital Signature WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! A 16-round Feistel cipher working on 64-bit blocks. Unlike DES, it can have varying key sizes ranging from 32 bits to 448 bits. Designed by Bruce Schneier. - Answer Blowfish Which of the following modes can be used to turn a block cipher into a stream cipher? - Answer Output feedback (OFB) and Counter Mode (CTR) Online business transactions between companies - Answer Class 4 certificates EFS is encryption for files while Bitlocker is used for full disk encryption - Answer EFS vs. Bitlocker Cryptanalysis attack that exploits vulnerabilities within the algorithm structure. - Answer Analytic attack Open-community and standardized version of SSL but TLS is more extensible and is backward compatible with SSL. - Answer Transport-Layer Security (TLS) Uses a block size of 128 bits and key sizes up to 256 bits. It is a Feistel cipher. Designed by Bruce Schneier, John Kelsey, Doug Whiting, David Wagner, Chris Hall, and Niels Ferguson. - Answer Twofish 160 bit hash - Answer SHA-1 Cryptographic attack that exploits the mathematics behind the birthday problem in the probability theory forces collisions within hashing functions. - Answer Birthday attack A process that puts a message into the least significant bits of a binary file is called what? - Answer Steganography Cryptanalysis attack that tries to uncover a mathematical problem from two different ends. - Answer Meet-in-the-middle attack Asymmetric encryption method developed in 1984. It is used in PGP implementations and GNU Privacy Guard Software. Consists of 3 parts: key generator, encryption algorithm, and decryption algorithm. - Answer El Gamal A combination of the ISAKMP and OAKLEY protocols. - Answer Internet Key Exchange (IKE) The payload of the message is protected - Answer Transport mode What did WPA replace RC4 with? - Answer TKIP (Temporal Key Integrity Protocol) WGU Course C839 - Intro to Cryptography Questions Correctly Answered!! N denotes natural numbers. These are also sometimes called the counting numbers. They are 1, 2, 3, etc. Z denotes the integers. These are whole numbers such as -1, 0, 1, 2, etc. Basically, this set is the natural numbers combined with zero and the negative numbers. Q denotes rational numbers (or the ratios of integers). They are any number that can be expressed as a ratio of two integers. Examples are 3/2, 17/4, and 1/5. . WGU Course C839 Intro to Cryptography; Questions With Correct Answers | Latest Update Graded A+ (2023/2024).