C839 - Pre-Assessment: Introduction to Cryptography

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 - Answer- X.509 v3 *Version 3* What is referenced to determine if a certificate has been revoked?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