Private-Key Encryption Security Quiz

What is the main difference between perfect secrecy and computational secrecy?

What does a (t, ϵ)-secure scheme guarantee?

Why is it more convenient to measure running time in terms of CPU cycles for (t, ϵ)-secure schemes?

Which block cipher mode is deterministic and cannot be CPA-secure?

In which block cipher mode is a uniform initialization vector (IV) of length n chosen?

Which block cipher mode has ciphertext length double the plaintext length in a CPA-secure construction?

Which block cipher mode involves encrypting a message of length l using a length-preserving block cipher?

Which block cipher mode uses an initialization vector (IV) for encryption?

What is the key space size for a private-key encryption scheme using a 128-bit key?

For c = 1 and n = 64, how many years does a 4 GHz processor with 16 cores require at most to break the scheme?

How are realistic adversaries modeled in cryptographic schemes?

Which of the following is a characteristic of a pseudorandom function?

In the context of distinguishing pseudorandom functions, what does the theorem state about the construction's security?

What is a characteristic of a strong pseudorandom permutation?

What is the definition of EAV-security in private-key encryption?

What is the key characteristic of a pseudorandom generator used in EAV-secure encryption schemes?

What is the role of semantic security in private-key encryption?

In the experiment PrivKA,Π (n), what is A given and what does it output?

What does CPA-Security for Multiple Encryptions involve?

What is the property of pseudorandom functions?

Computational secrecy requirement: Information about the encrypted message is leaked with a tiny probability to eavesdroppers with bounded computational power

Upper bounds the success probability of an adversary running for some specified time. A concrete definition of security takes the following form. A scheme is (t, ϵ)-secure is any adversary running for time at most t succeeds in breaking the scheme with probability at most ϵ.

How large can t be. How small should ϵ be.

CPA-secure private-key encryption scheme uses ______ function F

Distinguisher has no access to the key k

Strong pseudorandom ______ cannot be efficiently distinguished from a random ______

An event that occurs with probability $2^{-60}$ each second is expected to occur once every ______

A scheme is secure if for every probabilistic polynomial-time adversary A, the probability of A succeeding in the attack is ______

Both PPT adversaries and ______ probabilities of success are needed to allow practical encryption schemes

Semantic security is the analog of perfect secrecy for computationally bounded adversaries and is the first definition of computationally secure encryption to be proposed

______ is a form of security in private-key encryption where an adversary behaves the same, regardless of whether it observes an encryption of m0 or m1

A ______ is a polynomial-time deterministic algorithm for transforming a short, uniform bitstring called the seed into a longer, 'uniform-looking' output string

CPA-Security for Multiple Encryptions is stronger than ______

The LR-Oracle Experiment involves A being given 1 and oracle access to LRk,b (⋅, ⋅) and outputs a bit ______

The private-key encryption scheme has indistinguishable encryptions under a chosen-plaintext attack if for all PPT adversaries A there is a negligible function ______

ECB is deterministic and cannot be ______

Let F be a length-preserving block cipher with block length n. A uniform initialization vector (IV) of length n is ______. c0 = IV. For i = 1, … , l, ci := Fk (ci−1 ⊕ mi )

Let m = m1 , m2 , … , ml where mi ∈ {0, 1}. n Let F be a length-preserving block cipher with block length n. A uniform initialization vector (IV) of length n is ______.

Let m = m1 , m2 , … , ml where mi ∈ {0, 1} n Let F be a length-preserving block cipher with length n To encrypt a message of length l

Fortunately, there exist secure constructions based on block ciphers that have lower ______