question stringlengths 6 313 | choices listlengths 4 4 | answer stringclasses 4
values | source stringclasses 1
value | __index_level_0__ int64 1 337 |
|---|---|---|---|---|
Which of the following cryptographic primitives have a security level that is significantly lower than 80 bits? | [
"Symmetric key encryption with a secret key of 82 bits.",
"RSA signature scheme with a 1613-bit modulus.",
"ElGamal cryptosystem over a subgroup $H\\subset\\mathbb{Z}_p^*$ with a 1613-bit prime $p$ and $|H|\\approx 2^{70}$.",
"A hash function with the output of size 163 bits."
] | C | m1_pref_dataset | 201 |
What should the minimal length of the output of a hash function be to provide security against \emph{preimage attacks} of $2^{256}?$ | [
"$2^{256}$ bits.",
"$2^{512}$ bits.",
"$256$ bits.",
"$512$ bits."
] | C | m1_pref_dataset | 202 |
How is data integrity ensured in WEP? | [
"there is no integrity.",
"A3.",
"Michael.",
"HMAC."
] | A | m1_pref_dataset | 203 |
Tick the \textbf{non-commutative} operation. | [
"$+$ (addition) over $\\mathbb{Z}$",
"$\\oplus$ (exclusive-or)",
"$-$ (subtraction) over $\\mathbb{Z}$",
"$\\times$ (multiplication) over $\\mathbb{Z}$"
] | C | m1_pref_dataset | 204 |
Let $H$ be a hash function. Collision resistance means that \dots | [
"given $y$, it is hard to find $x$ such that $H(x)=y$",
"given $x$, it is hard to find $y$ such that $H(x)=y$",
"it is hard to find $x_1$ and $x_2\\neq x_1$ such that $H(x_1)=H(x_2)$",
"given $x_1$, it is hard to find $x_2\\neq x_1$ such that $H(x_1)=H(x_2)$"
] | C | m1_pref_dataset | 205 |
Select \emph{incorrect} statement. The exhaustive search | [
"can be used to find a secret key of AES.",
"is a brute force attack.",
"is not applicable against perfectly secure cipher.",
"runs in time polynomial in the length of the key."
] | D | m1_pref_dataset | 206 |
Choose the \emph{incorrect} statement. | [
"The key is always sent alongside the commitment.",
"Statisticaly hiding property is more desirable than computationally hiding.",
"A commitment scheme can be perfectly hiding.",
"A commitment scheme can be non-interactive."
] | A | m1_pref_dataset | 207 |
A Carmichael number is | [
"a prime number which cannot pass the Rabin-Miller test.",
"a composite number which often passes the Rabin-Miller test.",
"a prime number which cannot pass the Fermat test.",
"a composite number which often passes the Fermat test."
] | D | m1_pref_dataset | 208 |
We want to generate a $\ell$-bit prime. The complexity is roughly\dots | [
"$\\ell^2$",
"$\\ell^3$",
"$\\ell^4$",
"$\\ell^5$"
] | C | m1_pref_dataset | 209 |
The ElGamal cryptosystem is based on\dots | [
"nothing.",
"the discrete logarithm problem.",
"the RSA problem.",
"the factorization problem."
] | B | m1_pref_dataset | 210 |
Let $E$ be an elliptic curve. Solving which of the following problems would help you to break Elliptic Curve Diffie-Hellman (ECDH) over $E$? | [
"Let $P,R \\in E$. Given $P$ and $P+R$, compute $R$.",
"Let $P,Q \\in E$. Given $P$ and $Q$, compute the product between $P$ and $Q$, i.e., $P \\times Q$.",
"Let $P \\in E$ and $\\ell \\in \\mathbb{N}$. Given $P$ and $\\ell P$, compute $\\ell$.",
"Find a point which is not on the curve $E$."
] | C | m1_pref_dataset | 211 |
What is the encryption of the word ``SECRECY'' under the Vigen\`ere cipher using the key ``ZAB''? | [
"``REDQEDX''",
"``RDDQEDX''",
"``REDQEKX''",
"``REDUEDX''"
] | A | m1_pref_dataset | 212 |
A passive adversary can \ldots | [
"do nothing.",
"only listen to communications.",
"only interfere with client or server communications.",
"only replace some communication messages by others."
] | B | m1_pref_dataset | 213 |
Let $n$ be a positive integer. The Fermat test most likely outputs ``prime'' \dots | [
"only when $n$ is prime.",
"only when $n$ is non-prime.",
"when $n$ is prime or when $n$ is not a Carmichael number.",
"when $n$ is prime or when $n$ is a Carmichael number."
] | D | m1_pref_dataset | 214 |
When designing a cryptosystem that follows the rules of modern cryptography, we \dots | [
"must hide the design and our own cryptanalysis very well.",
"must assume that the adversary will learn everything about the cryptosystem.",
"can assume that the adversaries are not smarter than the designers.",
"must publish the whole design and our own cryptanalysis."
] | B | m1_pref_dataset | 215 |
Which one of these digital signature schemes is \emph{not} based on the Discrete Log problem? | [
"DSA",
"ECDSA",
"Pointcheval-Vaudenay",
"PKCS\\#1v$1.5$"
] | D | m1_pref_dataset | 216 |
Tick the \textbf{incorrect} assertion. | [
"One should use RSA-OAEP instead of plain RSA.",
"The ElGamal cryptosystem can be adapted to any group over which the discrete logarithm problem is hard.",
"Being able to factor large integers will help you break ECDSA.",
"To decrypt properly a Rabin ciphertext we usually assume that some redundancy was added... | C | m1_pref_dataset | 217 |
The result of $2^{2015} \bmod{9}$ is $\ldots$ | [
"2.",
"5.",
"4.",
"7."
] | B | m1_pref_dataset | 218 |
The complexities of the encryption and decryption in RSA with a modulus of $s$ bits are respectively within the order of magnitude \ldots | [
"$s^3$ and $s^3$",
"$s^4$ and $s^3$",
"$s^3$ and $s^4$",
"$s^4$ and $s^4$"
] | A | m1_pref_dataset | 219 |
Tick the \emph{false} assumption. | [
"Static Diffie-Hellman has forward secrecy.",
"If we run the static Diffie-Hellman protocol between Alice and Bob, the communications will always be the same.",
"Static Diffie-Hellman can be implemented over elliptic curves.",
"In ephemeral Diffie-Hellman, $g^x$ and $g^y$ are discarded at the end of the proto... | A | m1_pref_dataset | 220 |
A simple substitution cipher can be broken \dots | [
"by analysing the probability occurence of the language.",
"only by using a quantum computer.",
"by using the ENIGMA machine.",
"by using public-key cryptogaphy."
] | A | m1_pref_dataset | 221 |
Which one of the following notions means that ``the information should make clear who the author of it is''? | [
"authentication",
"steganograhy",
"privacy",
"confidentiality"
] | A | m1_pref_dataset | 222 |
Stream ciphers often use a nonce to \dots | [
"simplify the key schedule.",
"reduce the size of the secret key.",
"avoid the reuse of the key stream.",
"improve the efficiency of the automaton."
] | C | m1_pref_dataset | 223 |
Choose the \emph{correct} statement. | [
"$\\mathbb{Z}_n$ is a field $\\Leftrightarrow$ $n$ is a composite number",
"$\\mathbb{Z}_n$ is a field $\\Leftrightarrow$ $\\mathbb{Z}_n^* = \\mathbb{Z}_n$",
"$\\mathbb{Z}_n$ is a field $\\Leftrightarrow$ $n$ is a prime",
"$\\mathbb{Z}_n$ is a field $\\Leftrightarrow$ $\\mathbb{Z}_n^* = \\emptyset$"
] | C | m1_pref_dataset | 224 |
The group $\mathbb{Z}_{60}^*$ has \ldots | [
"16 elements.",
"60 elements.",
"59 elements.",
"32 elements."
] | A | m1_pref_dataset | 225 |
Which of the following integers has the square roots $\{2,3\}$ when taken modulo $5$ \textbf{and} the square roots $\{3,10\}$ when taken modulo $13$. | [
"$4$.",
"$9$.",
"$6$.",
"$5$."
] | B | m1_pref_dataset | 226 |
Pick the \emph{false} statement. | [
"A ring is always commutative: $ab=ba$",
"A ring is always associative: $(ab)c=a(bc)$",
"A ring is always distributive: $a(b+c)=ab+ac$, $(a+b)c=ac+bc$",
"A ring is always Abelian: $a+b = b+a$"
] | A | m1_pref_dataset | 227 |
Moore's Law ... | [
"is an empirical law.",
"says that the cost of computers doubles every 18 months.",
"will allow to break AES in 2015.",
"is a main reason for discarding MD5 hash function."
] | A | m1_pref_dataset | 228 |
Tick the \emph{false} assertion. The index of coincidence | [
"is a probability.",
"can help breaking Vigen\\`ere cipher.",
"is different for a random string than for some text in English.",
"is the best known attack against the Vernam cipher."
] | D | m1_pref_dataset | 229 |
Select the \emph{incorrect} statement. Pedersen Commitment is | [
"unconditionally hiding.",
"computationally binding.",
"based on the hardness of the discrete logarithm problem.",
"based on DSA."
] | D | m1_pref_dataset | 230 |
Select a correct statement | [
"Morse alphabet is a cipher",
"Morse alphabet is a code",
"Morse alphabet preserves confidentiality",
"Morse alphabet preserves authenticity"
] | B | m1_pref_dataset | 231 |
Let $p$ be a prime number. What is the cardinality of $\mathbf{Z}_p$? | [
"$p$",
"$p-1$",
"$\\varphi(p)$",
"$\\varphi(p-1)$"
] | A | m1_pref_dataset | 232 |
Due to the birthday paradox, a collision search in a hash function with $n$-bit output has complexity\dots | [
"$2^{\\sqrt{n}}$",
"$\\sqrt{2^n}$",
"$2^n$",
"$2^{n-1}$"
] | B | m1_pref_dataset | 233 |
Using a block cipher, we can build \ldots | [
"only hash functions.",
"only MACs.",
"only hash functions and MACs.",
"hash functions, MACs, and stream ciphers."
] | D | m1_pref_dataset | 234 |
What is the length in bits of the input and output of a DES S-Box respectively? | [
"6 and 6",
"4 and 6",
"6 and 4",
"4 and 4"
] | C | m1_pref_dataset | 235 |
Tick the \emph{minimal} assumption on the required channel to exchange the key of a Message Authentication Code (MAC): | [
"nothing.",
"authentication and integrity only.",
"confidentiality only.",
"authentication, integrity, and confidentiality."
] | D | m1_pref_dataset | 236 |
Tick the \emph{true} assertion among the followings: | [
"Visual cryptography is perfectly secure (at an unreasonable cost).",
"The Vernam cipher was invented by Kerckoff.",
"Just like coding theory, cryptography usually faces random noise.",
"Enigma has never been broken."
] | A | m1_pref_dataset | 237 |
Which of the following is well preserved by 2G? | [
"Confidentiality",
"Message Integrity",
"Challenge freshness",
"Authentication of Mobile Station"
] | D | m1_pref_dataset | 238 |
The collision resistance property of a hash function $H$ means that it is infeasible to\dots | [
"find $Y$ such that $H(X)=Y$ for a given $X$.",
"find $X$ such that $H(X)=Y$ for a given $Y$.",
"find $X'$ such that $H(X')=H(X)$ and $X\\ne X'$ for a given $X$.",
"find $X,X'$ such that $H(X)=H(X')$ and $X\\ne X'$."
] | D | m1_pref_dataset | 239 |
Compared to the plain RSA cryptosystem and for equivalent key sizes, the plain Elgamal cryptosystem has\dots | [
"a simpler key generation algorithm.",
"a simpler encryption algorithm.",
"a simpler decryption algorithm.",
"shorter ciphertexts."
] | A | m1_pref_dataset | 240 |
Consider the exhaustive search of a uniformly distributed key in a set of size $N$. Think of the possible strategies and their complexities. Which of the following is \textbf{not} possible (We assume that memory access is constant.) | [
"Find the key with precomputation: $0$, memory: $O(1)$, time: $O(N)$.",
"Find the key with precomputation: $O(N)$, memory: $O(N)$, time: $O(1)$.",
"Find the key with precomputation: $O(N)$, memory: $O(N^{2/3})$, time: $O(N^{2/3})$.",
"Find the key with precomputation: $0$, memory: $O(N)$, time: $O(1)$."
] | D | m1_pref_dataset | 241 |
Tick the \textbf{true} assertion. | [
"It is asymptotically harder to do a collision than to do a preimage attack.",
"The probability that a random number is prime increases whith the increase of size length.",
"If $f(n)\\in O(g(n))$ then $f(n)\\in \\Theta(g(n))$.",
"If $f(n)\\in \\Theta(g(n))$ then $f(n)\\in O(g(n))$."
] | D | m1_pref_dataset | 242 |
The Pohlig-Hellman algorithm can be used to \dots | [
"solve the DH problem when the order of the group is smooth.",
"solve the RSA factorization problem when $p-1$ has smooth order.",
"find square roots in $\\mathbb{Z}_n$, where $n=pq$ for $p,q$ two large primes.",
"compute the CRT of two numbers."
] | A | m1_pref_dataset | 243 |
Tick the \textbf{true} assertion. In a zero-knowledge interactive proof of knowledge, \ldots | [
"for any ppt verifier, any simulator can produce a transcript which is indistinguishable from the original conversation.",
"the proof of knowledge denotes that the prover does not know why the statement is true.",
"for any ppt verifier, there is a simulator which produces a conversation indistinguishable from t... | C | m1_pref_dataset | 244 |
Tick the \textbf{true} assertion. Let $X,Y$ be two random variables over the same probability space. Then, | [
"$X$ is always independent from $Y$.",
"$E(XY)=E(X)\\times E(Y)$, if $X$ and $Y$ are independent.",
"$\\Pr[X = x \\, \\text{and} \\, Y = y ] = \\Pr[X = x ] \\times \\Pr[Y = y]$.",
"$X+Y$ does not make sense."
] | B | m1_pref_dataset | 245 |
Tick the \textbf{false} assertion. | [
"Black-box ZK (zero knowledge) is a stronger notion than (simple) ZK.",
"We can give a black-box ZK protocol deciding 3-COL (coloring graphs with 3 colours).",
"The NP language has no ZK proofs.",
"We can give a ZK protocol deciding ISO (graph isomorphisms)."
] | C | m1_pref_dataset | 246 |
Tick the \textbf{true} assertion. The advantage of a distinguisher of two distributions $P_0$ and $P_1$ | [
"is always the Euclidean distance between $P_0$ and $P_1$.",
"is $\\mathsf{Adv}_{\\mathcal{A}} (P_0 , P_1 ) = \\Pr[P = P_1|A \\rightarrow 1]-\\Pr[P = P_0| A \\rightarrow 1]$.",
"is $\\mathsf{Adv}_{\\mathcal{A}} (P_0 , P_1 ) = \\Pr[A \\rightarrow 0|P = P_1 ]-\\Pr[A \\rightarrow 1|P = P_0]$.",
"can touch the st... | D | m1_pref_dataset | 247 |
The number of plaintext/ciphertext pairs required for a linear cryptanalysis is\dots | [
"$\\approx \\mathsf{LP}$",
"$\\approx \\frac{1}{\\mathsf{LP}}$",
"$\\approx \\frac{1}{\\mathsf{LP}^2}$",
"$\\approx \\log \\frac{1}{\\mathsf{LP}}$"
] | B | m1_pref_dataset | 248 |
Tick the \emph{incorrect} assertion. For a cipher $C$, decorrelation theory says that \ldots | [
"A decorrelation $0$ of order $1$ means perfect secrecy when used once.",
"$\\mathsf{BestAdv}_n(C,C^\\ast)=\\frac{1}{2}\\mathsf{Dec}^n_{\\left|\\left|\\cdot\\right|\\right|_a}(C)$.",
"A decorrelation $0$ of order $1$ always protects against linear cryptanalysis.",
"$\\mathsf{Dec}^n(C_1\\circ C_2) \\leq \\math... | C | m1_pref_dataset | 249 |
Given a function $f:\left\{ 0,1 \right\}^p \rightarrow \left\{ 0,1 \right\}^q$, given $a\in\left\{ 0,1 \right\}^p$ and $b \in \left\{ 0,1 \right\}^q$, we define $DP^{f}(a,b) = \Pr_{X}[f(X \oplus a) = f(X) \oplus b]$. We have that $\ldots$ | [
"$DP^f(0,b) = 1$ if and only if $b \\not= 0$.",
"$DP^f(a,a) =1$.",
"$\\sum_{a \\in \\{0,1\\}^p} \\sum_{b \\in \\{0,1\\}^q} DP^f(a,b)= 2^p $.",
"when $f$ is a permutation and $p=q$, $DP^f(a,0) = 1$."
] | C | m1_pref_dataset | 250 |
In linear cryptanalysis,\dots | [
"one needs to do a chosen plaintext attack.",
"one studies how the differences in the input propagate in the cipher.",
"one chooses the deviant property with the smallest bias in order to optimize the attack.",
"one needs to have about $\\frac{1}{LP}$ pairs of plaintext-ciphertext in order to recover the corr... | D | m1_pref_dataset | 251 |
The worst case complexity of an exaustive search (with memory) against DES is\dots | [
"$1$",
"$\\frac{2^{64}}{2}$",
"$2^{56}$",
"$2^{64}$"
] | C | m1_pref_dataset | 252 |
Who invented linear cryptanalysis? | [
"Mitsuru Matsui",
"Eli Biham",
"Serge Vaudenay",
"Adi Shamir"
] | A | m1_pref_dataset | 253 |
For a blockcipher $B:\{0,1\}^k\times \{0,1\}^n \rightarrow \{0,1\}^n$ that has decorrelation $Dec^q_{\| \cdot \|_{\infty}}(B,C^*)=d$ (from a perfect cipher $C^*$), the best advantage of \textit{any} distinguisher that makes $q$ queries is \ldots | [
"bounded by $d/2$.",
"not related to $d$; we have to use the $a$-norm to get a more general result.",
"bounded by $d$.",
"bounded by $d-\\frac{1}{2}$."
] | A | m1_pref_dataset | 254 |
I want to send a value to Bob without him knowing which value I sent and such that I cannot change my mind later when I reveal it in clear. I should use \dots | [
"a stream cipher.",
"a PRNG.",
"a commitment scheme.",
"a digital signature."
] | C | m1_pref_dataset | 255 |
Tick the \textbf{false} assertion. | [
"$\\mathcal{NP} \\subseteq \\mathcal{PSPACE}$",
"$\\mathcal{IP}\\ \\bigcap\\ \\mathcal{PSPACE} = \\emptyset$",
"$\\mathcal{IP} = \\mathcal{PSPACE}$",
"$\\mathcal{IP} \\supseteq \\mathcal{PSPACE}$"
] | B | m1_pref_dataset | 256 |
Tick the \textbf{true} assertion. $x\in \mathbf{Z}_{n}$ is invertible iff \ldots | [
"$\\varphi(n)= n-1$.",
"$x$ is prime.",
"$x$ is not prime.",
"$gcd(x,n) = 1$."
] | D | m1_pref_dataset | 257 |
Which of the following circuits does not change an input difference. | [
"A XOR to a constant gate.",
"An SBox.",
"A shift of all bits by one position to the right.",
"A non-linear circuit."
] | A | m1_pref_dataset | 258 |
Which one of these attacks is not a side channel attack? | [
"sound analysis.",
"electromagnetic fields analysis.",
"differential fault analysis.",
"brute force attack."
] | D | m1_pref_dataset | 259 |
Tick the \emph{correct} assertion. The maximum advantage of an \textbf{adaptive} distinguisher limited to $q$ queries between two random functions $F$ and $F^*$ is always\dots | [
"$\\frac{1}{2}|||[F]^q - [F^*]^q |||_{\\infty}$.",
"$\\frac{1}{2}|||[F]^q - [F^*]^q |||_{a}$.",
"$1$ when $F = F^*$.",
"lower than the advantage of the best \\textbf{non-adaptive} distinguisher."
] | B | m1_pref_dataset | 260 |
Tick the \textbf{false} assertion. A distinguisher can \ldots | [
"\\ldots be a first step towards key recovery in block ciphers.",
"\\ldots be assumed deterministic when it is computationally unbounded.",
"\\ldots factorize big numbers.",
"\\ldots differentiate the encryption of two known plaintexts."
] | C | m1_pref_dataset | 261 |
Consider any block cipher $C$ and a uniformly distributed random permutation $C^*$ on $\{0,1\}^\ell$. Then, for any $n \ge 1$ we always have\dots | [
"$[C^* \\circ C]^n = [C]^n$",
"$[C^* \\circ C]^n = [C^*]^n$",
"$[C^* \\circ C]^n = [C]^{2n}$",
"$[C^* \\circ C]^n = [C]^n + [C^*]^n$"
] | B | m1_pref_dataset | 262 |
Let $X$, $Y$, and $K$ be respectively the plaintext, ciphertext, and key distributions. $H$ denotes the Shannon entropy. The consequence of perfect secrecy is \dots | [
"$H(K) \\geq H(X)$",
"$H(K) \\leq H(X)$",
"$H(K,X) \\leq H(X)$",
"$H(Y) \\leq H(X)$"
] | A | m1_pref_dataset | 263 |
Tick the \textbf{true} assertion. A first preimage attack on a hash function H is \ldots | [
"\\ldots given $x$ find $y$ such that $H(x)=y$",
"\\ldots given $x$ find $x'\\neq x$ such that $H(x)=H(x')$",
"\\ldots given $y$ find $x$ such that $H(x)=y$",
"\\ldots find $x$ and $x'$ such that $x'\\neq x$ and $H(x)=H(x')$"
] | C | m1_pref_dataset | 264 |
In an interactive proof system for a language $L$, having $\beta$-soundness means that\dots | [
"if we run the protocol with input $x\\not\\in L$, with a \\textbf{malicious prover}, and a \\textbf{honest verifier} the probability that the protocol succeeds is upper-bounded by $\\beta$.",
"if we run the protocol with input $x\\in L$, with a \\textbf{malicious prover}, and a \\textbf{honest verifier} the prob... | A | m1_pref_dataset | 265 |
A proof system is computational-zero-knowledge if \dots | [
"for any PPT verifier and for any simulator $S$, $S$ produces an output which is hard to distinguish from the view of the protocol.",
"there exists a PPT simulator $S$ such that for any \\emph{honest} verifier, $S$ produces an output which is hard to distinguish from the view of the verifier.",
"for any PPT ver... | C | m1_pref_dataset | 266 |
Tick the \textbf{false} assertion. Assume that $C$ is a random permutation. | [
"BestAdv$_n(C,C^\\ast)=\\frac{1}{2}Dec^n_{\\left|\\left|\\left|\\cdot\\right|\\right|\\right|_a}(C)$",
"BestAdv$_n^{n.a.}(C,C^\\ast)=\\frac{1}{2}Dec^n_{\\left|\\left|\\left|\\cdot\\right|\\right|\\right|_\\infty}(C)$",
"$E(LP^{C}(a,b))\\leq 1$",
"$Dec^n(C\\circ C)\\leq Dec^n(C)^2$."
] | D | m1_pref_dataset | 267 |
Standard encryption threats do not include: | [
"Known-plaintext attacks.",
"Chosen-plaintext attacks.",
"Universal forgeries.",
"Key-recovery attacks."
] | C | m1_pref_dataset | 268 |
Tick the \textbf{false} assertion. In Linear Cryptanalysis, the corresponding mask circuit of \ldots | [
"\\ldots a XOR gate ($X\\oplus Y = Z$) is $a\\cdot Z=(a\\cdot X)\\oplus (a\\cdot Y)$",
"\\ldots a XOR to constant gate ($Y=X\\oplus K$) is $a\\cdot Y = (a\\cdot X)\\oplus (a\\cdot K)$",
"\\ldots a linear circuit ($Y=M\\times X$) is $a\\cdot Y = (M\\times a)\\cdot X$",
"\\ldots a duplicate gate ($X=Y=Z$) is $(... | C | m1_pref_dataset | 269 |
Tick the \textbf{true} assertion. In a zero-knowledge interactive proof for $L$, \ldots | [
"for any ppt verifier, there is a simulator which for any $x \\in L$ produces a conversation indistinguishable from the original conversation.",
"for any ppt verifier, for some $x \\in L$, any simulated conversation is indistinguishable from the original conversation.",
"the simulator imitates the verifier.",
... | A | m1_pref_dataset | 270 |
What is the Squared Euclidean Imbalance? | [
"$\\displaystyle P_0(x)\\sum_x(P_1(x)-P_0(x))^2$",
"$\\displaystyle\\frac{1}{P_0(x)}\\sum_x(P_1(x)-P_0(x))^2$",
"$\\displaystyle\\sum_x\\frac{(P_1(x)-P_0(x))^2}{P_0(x)}$",
"$\\displaystyle\\sum_x\\left(\\frac{P_1(x)}{P_0(x)}-1\\right)^2$"
] | C | m1_pref_dataset | 271 |
Tick the \textbf{false} assertion. A cipher with a good decorrelation of order 2 protects against \ldots | [
"\\ldots non-adaptive distinguishers limited to two queries.",
"\\ldots unbounded attacks.",
"\\ldots differential cryptanalysis.",
"\\ldots linear cryptanalysis."
] | B | m1_pref_dataset | 272 |
For any function $f:\{0,1\}^p\rightarrow \{0,1\}^q$ and for any $a\in\{0,1\}^p$, we have\ldots | [
"$\\Sigma _{b\\in \\{0,1\\}^q}\\mathsf{DP}^f(a,b)=1$",
"$\\Sigma _{b\\in \\{0,1\\}^q}\\mathsf{DP}^f(a,b)=0$",
"$\\Sigma _{b\\in \\{0,1\\}^q}\\mathsf{DP}^f(a,b)=\\frac{1}{2}$",
"$\\Sigma _{b\\in \\{0,1\\}^q}\\mathsf{DP}^f(a,b)=\\frac{1}{\\sqrt{2}}$"
] | A | m1_pref_dataset | 273 |
Tick the \textbf{incorrect} assertion regarding plain Rabin, i.e., Rabin without any redundancy. | [
"The Rabin Key Recovery Problem relies on the discrete logarithm problem.",
"Plain Rabin suffers from a chosen ciphertext key recovery attack.",
"The decryption of plain Rabin is ambiguous.",
"The Rabin Decryption Problem is equivalent to the factoring problem."
] | A | m1_pref_dataset | 274 |
Tick the \emph{incorrect} assertion. A cipher $C$ perfectly decorrelated at order 2 implies\dots | [
"perfect secrecy when used twice.",
"security against differential cryptanalysis.",
"security against linear cryptanalysis.",
"security against exhaustive search."
] | D | m1_pref_dataset | 275 |
Tick the \textbf{false} assertion. A distinguisher \ldots | [
"\\ldots can break PRNG.",
"\\ldots is an algorithm calling an oracle.",
"\\ldots recovers the secret key of a stream cipher.",
"\\ldots can differentiate the encryption of two known plaintexts."
] | C | m1_pref_dataset | 276 |
Tick the \emph{incorrect} assertion regarding the security of the Diffie-Hellman key exchange over a subgroup $\langle g \rangle \subset \mathbb{Z}_p^*$. | [
"$\\langle g \\rangle$ should have prime order.",
"We must ensure that $X\\in \\langle g \\rangle$ for every received $X$.",
"The binary representation of the output of the key exchange is a uniformly distributed bitstring.",
"We must ensure that $X\\neq1$ for every received $X$."
] | C | m1_pref_dataset | 277 |
Tick the \textbf{false} assertion. In Differential Cryptanalysis, the corresponding differential circuit of \ldots | [
"\\ldots a linear circuit ($Y=M\\times X$) is $\\Delta X=a\\Rightarrow \\Delta Y=^tM\\times a$",
"\\ldots a duplicate gate ($X=Y=Z$) is $\\Delta X=a\\Rightarrow \\Delta Y = \\Delta Z = a$",
"\\ldots a XOR gate ($X\\oplus Y = Z$) is $(\\Delta X=a,\\ \\Delta Y=b)\\Rightarrow \\Delta Z = a\\oplus b$",
"\\ldots a... | A | m1_pref_dataset | 278 |
Tick the \emph{correct} assertion. Linear cryptanalysis \ldots | [
"was invented long before the Caesar cipher.",
"is a chosen plaintext key recovery attack.",
"requires $\\frac{1}{DP}$ pairs of plaintext-ciphertext.",
"breaks DES with $2^{43}$ known plaintexts."
] | D | m1_pref_dataset | 279 |
Let $p>2$ be a prime. Then \dots | [
"for any $x \\in \\mathbb{Z}_p^*$, we have $x^p \\bmod{p} = 1$.",
"the set of quadratic residues modulo $p$ form a field.",
"the set of quadratic residues modulo $p$ is of order $(p-1)/2$.",
"$\\phi(p^2) = (p-1)^2$."
] | C | m1_pref_dataset | 280 |
Which assertion has not been proven? | [
"SAT $\\in P$.",
"SAT is $NP$-complete.",
"SAT $\\in NP$.",
"SAT $\\in IP$."
] | A | m1_pref_dataset | 281 |
Tick the \emph{incorrect} assertion. In hypothesis testing \ldots | [
"the statistical distance between $P_0$ and $P_1$ gives an upper bound on the advantage of all distinguishers using a single sample.",
"a distinguisher needs $\\frac{1}{C(P_0,P_1)}$ samples in order to be able to distinguish between $P_0$ and $P_1$.",
"a distinguisher can use a deviant property of a cipher $C$,... | D | m1_pref_dataset | 282 |
Consider the cipher defined using the key $K\in \{0,1\}^{64} $ by $$\begin{array}{llll} C : & \{0,1\}^{64} & \rightarrow & \{0,1\}^{64} \\ & x & \mapsto & C(x)=x \oplus K \\ \end{array} $$ Let $x=1\dots 11$, the value $\mathsf{LP}^{C_K}(x,x)$ is equal to | [
"$0$",
"$1/4$",
"$1/2$",
"$1$"
] | A | m1_pref_dataset | 283 |
Tick the \textbf{incorrect} assertion. Let $H:\left\{ 0,1 \right\}^*\rightarrow\left\{ 0,1 \right\}^n$ be a hash function. | [
"We can use $H$ to design a commitment scheme.",
"We can use $H$ to design a key derivation function.",
"Finding $x,y\\in\\left\\{ 0,1 \\right\\}^*$ such that $x\\neq y$ and $h(x) = h(y)$ can be done in $O(2^{n/2})$ time.",
"Given $x\\in\\left\\{ 0,1 \\right\\}^*$, finding a $y \\in \\left\\{ 0,1 \\right\\}^*... | D | m1_pref_dataset | 284 |
In which group is the discrete logarithm problem believed to be hard? | [
"In a subgroup of $\\mathbb{Z}_p^*$ with large prime order.",
"In $\\mathbb{Z}_n$, where $n= pq$ for two large primes $p$ and $q$.",
"In a group $G$ of smooth order.",
"In $\\mathbb{Z}_2^p$, for a large prime $p$."
] | A | m1_pref_dataset | 285 |
Consider two distributions $P_0,P_1$ with the same supports and a distinguisher $\mathcal{A}$ that makes $q$ queries. Tick the \textit{incorrect} assertion. | [
"When $q=1$, $\\mathsf{Adv}(\\mathcal{A})\\leq d(P_0,P_1)$ where $d$ is the statistical distance.",
"When $q>1$, $\\mathsf{Adv}(\\mathcal{A})\\leq \\frac{d(P_0,P_1)}{q}$ where $d$ is the statistical distance.",
"When $q=1$, the strategy ``return 1 $\\Leftrightarrow \\frac{P_0(x)}{P_1(x)}\\leq 1$'' achieves the ... | B | m1_pref_dataset | 286 |
What is the complexity of prime number generation for a prime of length $\ell$? | [
"$\\mathbf{O}\\left(\\frac{1}{\\ell^4}\\right)$",
"$\\mathbf{O}(\\ell^4)$",
"$\\Theta\\left(\\frac{1}{\\ell^4}\\right)$",
"$\\Theta(\\ell^4)$"
] | B | m1_pref_dataset | 287 |
In ElGamal signature scheme, if we avoid checking that $0 \leq r < p$ then \ldots | [
"\\ldots a universal forgery attack is possible.",
"\\ldots an existential forgery attack is avoided.",
"\\ldots we can recover the secret key.",
"\\ldots we need to put a stamp on the message."
] | A | m1_pref_dataset | 288 |
Tick the \textbf{true} assertion. MAC is \ldots | [
"\\ldots a computer.",
"\\ldots the name of a dish with chili.",
"\\ldots a Message Authentication Code.",
"\\ldots the encryption of KEY with the Ceasar cipher."
] | C | m1_pref_dataset | 289 |
For $K$ a field, $a,b\in K$ with $4a^3+27b^2 \neq 0$, $E_{a,b}(K)$ is | [
"a field.",
"a group.",
"a ring.",
"a ciphertext."
] | B | m1_pref_dataset | 290 |
The number of plaintext/ciphertext pairs required for a differential cryptanalysis is\dots | [
"$\\approx DP$",
"$\\approx \\frac{1}{DP}$",
"$\\approx \\frac{1}{DP^2}$",
"$\\approx \\log \\frac{1}{DP}$"
] | B | m1_pref_dataset | 291 |
Given the distribution $P_0$ of a normal coin, i.e. $P_0(0)=P_0(1)=\frac{1}{2}$, and distribution $P_1$ of a biased coin, where $P_1(0)=\frac{1}{3}$ and $P_1(1) = \frac{2}{3}$ , the maximal advantage of a distinguisher using a single sample is\dots | [
"$\\frac{1}{6}$.",
"$3$.",
"$\\frac{1}{3}$.",
"$0$."
] | A | m1_pref_dataset | 292 |
To how many plaintexts we expect to decrypt a ciphertext in the Rabin cryptosystem when we don't use redundancy? | [
"4.",
"2.",
"1.",
"8."
] | A | m1_pref_dataset | 293 |
For an interactive proof system, the difference between perfect, statistical and computational zero-knowledge is based on \ldots | [
"\\ldots the distinguishability between some distributions.",
"\\ldots the percentage of recoverable information from a transcript with a honest verifier.",
"\\ldots the number of times the protocol is run between the prover and the verifier.",
"\\ldots whether the inputs are taken in $\\mathcal{P}$, $\\mathc... | A | m1_pref_dataset | 294 |
What is the name of the encryption threat that corresponds to \emph{force the sender to encrypt some messages selected by the adversary}? | [
"Chosen Ciphertext Attack",
"Chosen Plaintext Attack",
"Known Ciphertext Attack",
"Known Plaintext Attack"
] | B | m1_pref_dataset | 295 |
Let $C$ be a perfect cipher with $\ell$-bit blocks. Then, \dots | [
"for $x_1 \\neq x_2$, $\\Pr[C(x_1) = y_1, C(x_2)=y_2] = \\frac{1}{2^{2\\ell}}$.",
"the size of the key space of $C$ should be at least $(2^{\\ell}!)$.",
"given pairwise independent inputs to $C$, the corresponding outputs are independent and uniformly distributed.",
"$C$ has an order $3$ decorrelation matrix ... | B | m1_pref_dataset | 296 |
The exponent of the group $\mathbb{Z}_9^*$ is | [
"6.",
"9.",
"8.",
"3."
] | A | m1_pref_dataset | 297 |
Tick the \emph{incorrect} statement. When $x\rightarrow+\infty$ \ldots | [
"$x^3 + 2x + 5 = \\mathcal{O}(x^3)$.",
"$\\frac{1}{x^2} = \\mathcal{O}(\\frac{1}{x})$.",
"$2^{\\frac{x}{\\log x}} = \\mathcal{O}(2^x)$.",
"$n^x = \\mathcal{O}(x^n)$ for any constant $n>1$."
] | D | m1_pref_dataset | 298 |
In order to avoid the Bleichenbacher attack in ElGamal signatures, \ldots | [
"\\ldots authors should put their name in the message.",
"\\ldots groups of prime order should be used.",
"\\ldots groups of even order should be used.",
"\\ldots groups with exponential number of elements should be used."
] | B | m1_pref_dataset | 299 |
Tick the \textbf{incorrect} assumption. A language $L$ is in NP if\dots | [
"$x \\in L$ can be decided in polynomial time.",
"$x \\in L$ can be decided in polynomial time given a witness $w$.",
"$L$ is NP-hard.",
"$L$ (Turing-)reduces to a language $L_2$ with $L_2$ in $P$, i.e., if there is a polynomial deterministic Turing machine which recognizes $L$ when plugged to an oracle recog... | C | m1_pref_dataset | 300 |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.