Cryptography, Encryption, Hashes Flashcards
Symmetric encryption is used primarily to provide confidentiality.(T/F)
True
Two of the most important applications of public-key encryption are digital signatures and key management.(T/F)
True
The secret key is one of the inputs to a symmetric-key encryption algorithm.(T/F)
True
The strength of a hash function against brute-force attacks depends on the length of the hash code produced by the algorithm.(T/F)
True
Public-key algorithms are based on simple operations on bit patterns. (T/F)
False
On average, ________ of all possible keys must be tried in order to achieve success with a brute-force attack.
half
If the only form of attack that could be made on an encryption algorithm is brute-force, then the way to counter such attacks would be to ________ .
use longer keys
________ is a procedure that allows communicating parties to verify that received or stored messages are authentic.
Message authentication
The purpose of a ________ is to produce a ?fingerprint? of a file, message, or other block of data.
hash function
A _________ is created by using a secure hash function to generate a hash value for a message and then encrypting the hash code with a private key.
digital signature
Symmetric encryption is also referred to as secret-key or single-key encryption.(T/F)
True
The ciphertext-only attack is the easiest to defend against.(T/F)
True
A brute-force approach involves trying every possible key until an intelligible translation of the ciphertext into plaintext is obtained.(T/F)
True
AES uses a Feistel structure.(T/F)
False
Each block of 64 plaintext bits is encoded independently using the same key? is a description of the CBC mode of operation.(T/F)
False
Timing attacks are only applicable to RSA.(T/F)
False
Using PKCS (public-key cryptography standard), when RSA encrypts the same message twice, different ciphertexts will be produced.(T/F)
True
The Diffie-Hellman algorithm depends for its effectiveness on the difficulty of computing discrete logarithms.(T/F)
True
A key exchange protocol is vulnerable to a man-in-the-middle attack if it does not authenticate the participants.(T/F)
True
Just like RSA can be used for signature as well as encryption, Digital Signature Standard can also be used for encryption.(T/F)
False
In general, public key based encryption is much slower than symmetric key based encryption. (T/F)
True
________ is the original message or data that is fed into the encryption process as input.
Plaintext
Which of the following would allow an attack that to know the (plaintext of) current message must be the same as one previously transmitted because their ciphtertexts are the same?
ECB
________ is a term that refers to the means of delivering a key to two parties that wish to exchange data without allowing others to see the key.
Key distribution technique
Which of the following feature can only be provided by public-key cryptography?
Non-repudiation
Cryptographic systems are generically classified by _______.
A. the type of operations used for transforming plaintext to ciphertext
B. the number of keys used
C. the way in which the plaintext is processed
________ attacks have several approaches, all equivalent in effort to factoring the product of two primes.
Mathematical
________ are analogous to a burglar guessing a safe combination by observing how long it takes to turn the dial from number to number.
Timing attacks
_________ was the first published public-key algorithm.
Diffie-Hellman
The principal attraction of ________ compared to RSA is that it appears to offer equal security for a far smaller bit size, thereby reducing processing overhead.
ECC
SHA is perhaps the most widely used family of hash functions.(T/F)
True
SHA-1 is considered to be very secure.(T/F)
False
HMAC can be proven secure provided that the embedded hash function has some reasonable cryptographic strengths.(T/F)
True
The additive constant numbers used in SHA-512 are random-looking and are hardcoded in the algorithm.(T/F)
True
The strong collision resistance property subsumes the weak collision resistance property.(T/F)
True
Cryptographic hash functions generally execute faster in software than conventional encryption algorithms such as DES and AES.(T/F)
True
A hash function such as SHA-1 was not designed for use as a MAC and cannot be used directly for that purpose because it does not rely on a secret key.(T/F)
True
It is a good idea to use sequentially increasing numbers as challenges in security protocols.(T/F)
False
Assuming that Alice and Bob have each other?s public key. In order to establish a shared session key, Alice just needs to generate a random k, encrypt k using Bob?s public key, and send the encrypted k to Bob and then Bob will know he has a key shared with Alice. (T/F)
False
SHA-1 produces a hash value of _______ bits.
160
The DSS makes use of the _______ and presents a new digital signature technique, the Digital Signature Algorithm (DSA).
SHA-1
