WGU C839 - Pre-Assessment: Introduction to Cryptography(Q & A)2023

WGU C839 - Pre-Assessment: Introduction to Cryptography(Q & A)2023 Which encryption standard uses the same key to encrypt and decrypt messages? - Answer Symmetric Key Encryption Which algorithm is designated as a Type 2 product by the National Security Agency (NSA)? - Answer SKIPJACK What is the most commonly used format for certificates? - Answer X.509 v3 *Version 3* What is referenced to determine if a certificate has been revoked? - Answer Certificate Revocation List *(CRL)* What needs to be installed on *end users' computers* to allow them to *trust* applications that have been *digitally signed* by the developer? - Answer Sender's public key *(DEVELOPER's)* Which type of certificate *must be certified by an authority* to verify it with other participants? - Answer Public Certificate What is an attribute of the Rivest Cipher 4 (RC4) algorithm? - Answer It requires a unique nonce. *(# used ONCE)* Which mode generates the key stream with a nonce and incrementing value? - Answer Counter (CTR) *Generates the next keystream block* by encrypting successive *values* of a "counter" Which mode is a stream algorithm that concatenates an incrementing value with a nonce? - Answer Counter (CTR) Which key would an administrator use to encrypt data so *only the CEO can decrypt it?* - Answer CEO's public key Remember, when a specific person in an organization is the *ONLY* one you want to *DECRYPT* something, you must have their *PUBLIC* key What is the result of a hash function? - Answer Digest What is used to efficiently encrypt *large files?* - Answer Symmetric encryption An administrator needs to encrypt the following word with the Atbash cipher: *security* Which ciphertext is correct? - Answer hvxfirgb Remember this is a Mono-Alphabet Substitution Cipher that replaces each character with its corresponding alphabet character *IE: A=Z, B=Y, C=X, etc...* Which cryptographic algorithm has a 128-bit *HASH* size? - Answer Message *Digest* Algorithm 5 (MD5) Which characteristic makes a hashing function suitable for use in signature schemes? - Answer Collision resistance *Of the many properties that a good hash function should have, the one that is mentioned most often is collision resistance.* Which attribute of a hashing function makes a *birthday attack possible?* - Answer *Partial-message collision* The partial-message collision attacks *all rely on birthday attacks* Which *hash* algorithm produces a 160-bit output value? - Answer SHA-1 What does cipher block chaining (CBC) use *with the key to encrypt subsequent blocks* of plaintext? - Answer Previous generated ciphertext Which mode produces the same ciphertext from two identical plaintext blocks? - Answer Electronic codebook (ECB) There are many situations in which large blocks of text are repeated. For example, this chapter contains the words "ciphertext block" many times. If two of the occurrences happen to line up on a block boundary, then a plaintext block value will be repeated Which encryption *mode is least secure?* - Answer Electronic codebook (ECB) What is the mathematical formula used for symmetric decryption? - Answer *P = E (K,C)* P = Plain text E = Encryption/Decryption K = Key C = Cipher Text *Remember, if you DECRYPT something, you want to know the PLAIN TEXT* Which algorithm relies on factoring the product of large prime numbers? - Answer RSA Which *encryption technology* is a serial *combination* of hashing, data compression, symmetric-key cryptography, and public key infrastructure (PKI) and can be used for encrypting texts, emails, files, and directories or for full disk encryption? - Answer Pretty Good Privacy (PGP) *Remember, this is NOT an ALGORITHM, but... it uses other established Asymmetric and Symmetric Algorithms* Which concept stipulates that algorithms should be openly shared and scrutinized, but keys must be absolutely secured? - Answer Kerckhoffs's principle Which encryption process *minimizes known plaintext attacks* against Advanced Encryption Standard (AES)? - Answer Randomizing the initialization vector