dataset
stringclasses 1
value | id
stringlengths 11
13
| question
stringlengths 64
1.92k
| choices
stringlengths 12
727
| answer
stringclasses 4
values |
|---|---|---|---|---|
mcq_train
|
mcq_train_201
|
Question: Which one of the following notions means that ``the information must be protected against any malicious modification''?
Options: privacy., integrity., confidentiality., reliability.
|
privacy., integrity., confidentiality., reliability.
|
B
|
mcq_train
|
mcq_train_202
|
Question: Confidentiality means that:
Options: the message can be read by anyone., information should not leak to any unexpected party., the message should make clear who the author is., the information must be protected against any malicious modification.
|
the message can be read by anyone., information should not leak to any unexpected party., the message should make clear who the author is., the information must be protected against any malicious modification.
|
B
|
mcq_train
|
mcq_train_203
|
Question: Which of the following acronyms does not designate a mode of operation?
Options: CBC, CTR, CRC, ECB
|
CBC, CTR, CRC, ECB
|
C
|
mcq_train
|
mcq_train_204
|
Question: Select the \emph{incorrect} statement. The brute force attack \dots
Options: can be applicable after decades according to Moore's law., can break a cipher with a $128$-bit key on your PC today., has higher worst case complexity than average case complexity., refers to a way of getting the secret key, exhaustively.
|
can be applicable after decades according to Moore's law., can break a cipher with a $128$-bit key on your PC today., has higher worst case complexity than average case complexity., refers to a way of getting the secret key, exhaustively.
|
B
|
mcq_train
|
mcq_train_205
|
Question: WEP \dots
Options: provides good confidentiality., provides good message integrity., provides good authentication., is badly broken.
|
provides good confidentiality., provides good message integrity., provides good authentication., is badly broken.
|
D
|
mcq_train
|
mcq_train_206
|
Question: The DES key schedule\dots
Options: \dots is based on a Feistel scheme., \dots takes as an input a key of 128 bits., \dots generates 16 subkeys., \dots in only used during the encryption phase, not during the decryption phase.
|
\dots is based on a Feistel scheme., \dots takes as an input a key of 128 bits., \dots generates 16 subkeys., \dots in only used during the encryption phase, not during the decryption phase.
|
C
|
mcq_train
|
mcq_train_207
|
Question: How many generators do we have in a group of order $13$?
Options: 13., 12., 6., 2.
|
13., 12., 6., 2.
|
B
|
mcq_train
|
mcq_train_208
|
Question: Which of the following attacks needs no precomputation.
Options: Exhaustive search., Dictionary attack., Meet-in-the-middle attack., A time memory tradeoff.
|
Exhaustive search., Dictionary attack., Meet-in-the-middle attack., A time memory tradeoff.
|
A
|
mcq_train
|
mcq_train_209
|
Question: Which one of these is \emph{not} a hard computational problem?
Options: Factoring., Extracting square roots., Computing the Jacobi symbol., Computing the discrete log.
|
Factoring., Extracting square roots., Computing the Jacobi symbol., Computing the discrete log.
|
C
|
mcq_train
|
mcq_train_210
|
Question: Select the \textbf{most accurate} answer. For a hash function to be secure (\textbf{but still efficient}) against collision attacks in 2015, the output length should be\dots
Options: around 80 bits., around 160 bits., around 512 bits., around 1024 bits.
|
around 80 bits., around 160 bits., around 512 bits., around 1024 bits.
|
B
|
mcq_train
|
mcq_train_211
|
Question: Tonelli Algorithm is for ...
Options: computing the discrete logarithm., finding the inverse of an element in $\mathbb{Z}$., finding the square-root of an integer in $\mathbb{Z}_p^*$., solving the extended Euclidean algorithm $\mathbb{Z}$.
|
computing the discrete logarithm., finding the inverse of an element in $\mathbb{Z}$., finding the square-root of an integer in $\mathbb{Z}_p^*$., solving the extended Euclidean algorithm $\mathbb{Z}$.
|
C
|
mcq_train
|
mcq_train_212
|
Question: Select the \emph{incorrect} statement
Options: RC4, A5/1, E0 are stream ciphers, MD4, MD5, SHA0, SHA1 are hash functions, DES, AES are block ciphers, ECB, KDF, PRF are commitment schemes
|
RC4, A5/1, E0 are stream ciphers, MD4, MD5, SHA0, SHA1 are hash functions, DES, AES are block ciphers, ECB, KDF, PRF are commitment schemes
|
D
|
mcq_train
|
mcq_train_213
|
Question: Let $(G,+), (H,\times)$ be two groups and $f:G\to H$ be an homomorphism. For $x_1,x_2 \in G$, we have:
Options: $f(x_1) + f(x_2)=f(x_1)\times f(x_2)$, $f(x_1 + x_2)=f(x_1)\times f(x_2)$, $f(x_1 + f(x_2))=f(x_1\times f(x_2))$, $f(x_1 \times x_2)=f(x_1)+ f(x_2)$
|
$f(x_1) + f(x_2)=f(x_1)\times f(x_2)$, $f(x_1 + x_2)=f(x_1)\times f(x_2)$, $f(x_1 + f(x_2))=f(x_1\times f(x_2))$, $f(x_1 \times x_2)=f(x_1)+ f(x_2)$
|
B
|
mcq_train
|
mcq_train_214
|
Question: Which of the following terms represents a mode of operation which transforms a block cipher into a stream cipher?
Options: 3DES, CBC, ECB, CTR
|
3DES, CBC, ECB, CTR
|
D
|
mcq_train
|
mcq_train_215
|
Question: The Shannon theorem states that perfect secrecy implies...
Options: $H(K)=H(X)$, $H(Y)\geq H(X)$, $H(K)\geq H(X)$, $H(Y)\leq H(X)$
|
$H(K)=H(X)$, $H(Y)\geq H(X)$, $H(K)\geq H(X)$, $H(Y)\leq H(X)$
|
C
|
mcq_train
|
mcq_train_216
|
Question: Tick the \textbf{false} statement. The Shannon Encryption Model ...
Options: requires a black-box encryption model., assumes a known input distribution., assumes the key is independent from the message., requires the correctness property $\Pr[C_K^{-1}(C_K(X))=X]=1$.
|
requires a black-box encryption model., assumes a known input distribution., assumes the key is independent from the message., requires the correctness property $\Pr[C_K^{-1}(C_K(X))=X]=1$.
|
A
|
mcq_train
|
mcq_train_217
|
Question: Select the \emph{incorrect} statement. The UMTS improves the security of GSM using
Options: authentication of the challenge., integrity protection., A6/1 for encryption., protection against replay attacks.
|
authentication of the challenge., integrity protection., A6/1 for encryption., protection against replay attacks.
|
C
|
mcq_train
|
mcq_train_218
|
Question: Let $n$ be an integer. The extended Euclidean algorithm is typically used to\dots
Options: \dots perform the addition of two integers in $\mathbf{Z}_n^*$., \dots compute the inverse of an element in $\mathbf{Z}_n^*$., \dots compute the square of an element of $\mathbf{Z}_n^*$., \dots compute the order of $\mathbf{Z}_n^*$.
|
\dots perform the addition of two integers in $\mathbf{Z}_n^*$., \dots compute the inverse of an element in $\mathbf{Z}_n^*$., \dots compute the square of an element of $\mathbf{Z}_n^*$., \dots compute the order of $\mathbf{Z}_n^*$.
|
B
|
mcq_train
|
mcq_train_219
|
Question: If we need to create a channel that protects confidentiality and we have at our disposal a channel that protects integrity and authenticity, we need to use
Options: symmetric key encryption., message authentication codes., public key encryption., digital signatures.
|
symmetric key encryption., message authentication codes., public key encryption., digital signatures.
|
C
|
mcq_train
|
mcq_train_220
|
Question: A \textit{Cryptographic Certificate} is the $\ldots$
Options: signature of the user who certifies that a public key belongs to the authority., signature of the user who certifies that a public key belongs to the user., signature of the authority who certifies that a public key belongs to a specific user., diploma which certifies that one has taken the Cryptography and Security Course.
|
signature of the user who certifies that a public key belongs to the authority., signature of the user who certifies that a public key belongs to the user., signature of the authority who certifies that a public key belongs to a specific user., diploma which certifies that one has taken the Cryptography and Security Course.
|
C
|
mcq_train
|
mcq_train_221
|
Question: The Advanced Encryption Standard (AES) is based on arithmetics on\dots
Options: $\mathrm{GF}(256)$, $\mathbf{Z}_{2^8}^*$, $\mathbf{Q}\setminus \{0\}$, $\mathbf{Z}_{2^8}$
|
$\mathrm{GF}(256)$, $\mathbf{Z}_{2^8}^*$, $\mathbf{Q}\setminus \{0\}$, $\mathbf{Z}_{2^8}$
|
A
|
mcq_train
|
mcq_train_222
|
Question: Tick the \emph{incorrect} assertion. In \emph{all} finite Abelian groups $(G,+)$ \ldots
Options: the order of any element divides the order of the group., all the elements are generators., the operation $+$ is commutative., the neutral element has order $1$.
|
the order of any element divides the order of the group., all the elements are generators., the operation $+$ is commutative., the neutral element has order $1$.
|
B
|
mcq_train
|
mcq_train_223
|
Question: The needed number of DES operations to attack DES is about ...
Options: $2^{54}.$, $2^{64}.$, $2^{128}.$, $2^{256}.$
|
$2^{54}.$, $2^{64}.$, $2^{128}.$, $2^{256}.$
|
A
|
mcq_train
|
mcq_train_224
|
Question: Which algorithm can be typically used in order to generate a prime number?
Options: The Left to Right Algorithm, The Extended Euclidean Algorithm, The Miller-Rabin Test, The Tonelli Algorithm
|
The Left to Right Algorithm, The Extended Euclidean Algorithm, The Miller-Rabin Test, The Tonelli Algorithm
|
C
|
mcq_train
|
mcq_train_225
|
Question: Tick the \emph{correct} assertion. In RSA with public key $(e,N)$ and private key $(d,N)$ \ldots
Options: the key generation requires that $\gcd(e,N) = 1$., decryption does not work for some $y \in \mathbb{Z}_N$ for which $\gcd(y,N) \not= 1$., if we know $\phi(N)$, the ciphertext $y$ and the public key, we can decrypt $y$., in order to decrypt we need to have $e^d \equiv 1 \pmod{N}$.
|
the key generation requires that $\gcd(e,N) = 1$., decryption does not work for some $y \in \mathbb{Z}_N$ for which $\gcd(y,N) \not= 1$., if we know $\phi(N)$, the ciphertext $y$ and the public key, we can decrypt $y$., in order to decrypt we need to have $e^d \equiv 1 \pmod{N}$.
|
C
|
mcq_train
|
mcq_train_226
|
Question: Tick the \emph{correct} assertion concerning WPA2
Options: WPA2 uses RC4., WPA2 uses AES., WPA2 uses 64-bit keys., WPA2 is badly broken.
|
WPA2 uses RC4., WPA2 uses AES., WPA2 uses 64-bit keys., WPA2 is badly broken.
|
B
|
mcq_train
|
mcq_train_227
|
Question: Tick the \textbf{false} statement regarding Kerckhoffs' principle.
Options: The system must be practically, if not mathematically, indecipherable., Besides keeping the key secret, the cryptosystem must also be kept secret., It must be applicable to telegraphic correspondence., Its key must be communicable and retainable without the help of written notes, and changeable or modifiable at the will of the correspondents.
|
The system must be practically, if not mathematically, indecipherable., Besides keeping the key secret, the cryptosystem must also be kept secret., It must be applicable to telegraphic correspondence., Its key must be communicable and retainable without the help of written notes, and changeable or modifiable at the will of the correspondents.
|
B
|
mcq_train
|
mcq_train_228
|
Question: Let $H$ be a hash function based on the Merkle-Damg{\aa}rd construction. The Merkle-Damg{\aa}rd theorem says that \dots
Options: \dots $H$ is collision-resistant when the compression function is collision-resistant., \dots the compression function is collision-resistant when $H$ is collision-resistant., \dots $H$ is collision-resistant., \dots $H$ is not collision-resistant.
|
\dots $H$ is collision-resistant when the compression function is collision-resistant., \dots the compression function is collision-resistant when $H$ is collision-resistant., \dots $H$ is collision-resistant., \dots $H$ is not collision-resistant.
|
A
|
mcq_train
|
mcq_train_229
|
Question: Consider a blockcipher $\mathsf{B}:\mathcal{K}\times\{0,1\}^n \rightarrow \{0,1\}^n$ with $|\mathcal{K}|=N$ for which we choose a secret key $K\in\mathcal{K}$ uniformly at random. Tick the \textit{correct} assertion.
Options: If $\mathsf{B}$ is secure against known-plaintext decryption attack, then it is surely secure against ciphertext-only key recovery attack., If $\mathsf{B}$ is secure against known-plaintext decryption attack, then it is surely secure against chosen-ciphertext decryption attack., It is possible to recover $K$ with precomputation: $O(N^{2/3})$, memory: $O(N^{2/3})$, time: $O(1)$., It is possible to recover $K$ key with precomputation: $O({1})$, memory: $O(N)$, time: $O(1)$.
|
If $\mathsf{B}$ is secure against known-plaintext decryption attack, then it is surely secure against ciphertext-only key recovery attack., If $\mathsf{B}$ is secure against known-plaintext decryption attack, then it is surely secure against chosen-ciphertext decryption attack., It is possible to recover $K$ with precomputation: $O(N^{2/3})$, memory: $O(N^{2/3})$, time: $O(1)$., It is possible to recover $K$ key with precomputation: $O({1})$, memory: $O(N)$, time: $O(1)$.
|
A
|
mcq_train
|
mcq_train_230
|
Question: The $n^2$ problem ...
Options: is dealt with thanks to Moore's Law., is a consequence of Murphy's Law., is a direct consequence of the Kerchkoffs Principles., appears when $n$ users need to communicate to each other using a symmetric cipher.
|
is dealt with thanks to Moore's Law., is a consequence of Murphy's Law., is a direct consequence of the Kerchkoffs Principles., appears when $n$ users need to communicate to each other using a symmetric cipher.
|
D
|
mcq_train
|
mcq_train_231
|
Question: A passive adversary\dots
Options: can only listen to the communications., can play the man-in-the-middle., can only alter messages., can delete messages.
|
can only listen to the communications., can play the man-in-the-middle., can only alter messages., can delete messages.
|
A
|
mcq_train
|
mcq_train_232
|
Question: Tick the \textbf{true} statement regarding RSA Cryptosystem.
Options: $(e,N,\varphi(N))$ are the public parameters., $e$ is a valid public key if $\gcd(e,N)=1$., Encryption and decryption are performed with the same key., $ed \equiv 1 \pmod{\varphi(N)}$.
|
$(e,N,\varphi(N))$ are the public parameters., $e$ is a valid public key if $\gcd(e,N)=1$., Encryption and decryption are performed with the same key., $ed \equiv 1 \pmod{\varphi(N)}$.
|
D
|
mcq_train
|
mcq_train_233
|
Question: The Vernam cipher\dots
Options: \dots is perfectly secure (if used in a proper way)., \dots can be broken using an index of coincidence., \dots is always less secure than DES., \dots has a security which depends on the Moore law.
|
\dots is perfectly secure (if used in a proper way)., \dots can be broken using an index of coincidence., \dots is always less secure than DES., \dots has a security which depends on the Moore law.
|
A
|
mcq_train
|
mcq_train_234
|
Question: Which protocol does \emph{not} use RC4.
Options: WEP, WPA, WPA2, TLS
|
WEP, WPA, WPA2, TLS
|
B
|
mcq_train
|
mcq_train_235
|
Question: Which of the following is a mode of operation for blockciphers that requires a non-repeating IV (a nonce) to be secure?
Options: ECB, CBC, TCS, CTR
|
ECB, CBC, TCS, CTR
|
D
|
mcq_train
|
mcq_train_236
|
Question: How many generators are there in $\mathbb{Z}_n$?
Options: $1$, $n-1$, $n$, $\varphi (n)$
|
$1$, $n-1$, $n$, $\varphi (n)$
|
D
|
mcq_train
|
mcq_train_237
|
Question: Using salt for UNIX passwords \ldots
Options: allows to speed up the verification for the server., makes the protocol secure against computationally unbounded adversary., allows to transmit the password over a non confidential channel without compromising the security., helps preventing dictionary attacks.
|
allows to speed up the verification for the server., makes the protocol secure against computationally unbounded adversary., allows to transmit the password over a non confidential channel without compromising the security., helps preventing dictionary attacks.
|
D
|
mcq_train
|
mcq_train_238
|
Question: One can find a collision in a hash function $h\colon \{0,1\}^* \rightarrow \{0,1\}^n$ with expected time complexity\dots
Options: $\Theta(\sqrt{n})$., $\Theta(n)$., $\Theta(2^n)$., $\Theta(2^{n/2})$.
|
$\Theta(\sqrt{n})$., $\Theta(n)$., $\Theta(2^n)$., $\Theta(2^{n/2})$.
|
D
|
mcq_train
|
mcq_train_239
|
Question: Tick the \textbf{false} statement regarding the Enigma machine.
Options: It is an electro-mechanical encryption device used by German armies in World War 2., Its specifications are secret., Its secret parameters are: ordered permutations, an involution, and a number., It was patented in 1918.
|
It is an electro-mechanical encryption device used by German armies in World War 2., Its specifications are secret., Its secret parameters are: ordered permutations, an involution, and a number., It was patented in 1918.
|
B
|
mcq_train
|
mcq_train_240
|
Question: One of the following ciphers is a \emph{block} cipher. Which one?
Options: AES, RC4, A5/1, MD5
|
AES, RC4, A5/1, MD5
|
A
|
mcq_train
|
mcq_train_241
|
Question: Compute $\phi(90)$.
Options: $36$., $24$., $16$., $48$.
|
$36$., $24$., $16$., $48$.
|
B
|
mcq_train
|
mcq_train_242
|
Question: Let $p$ and $q$ be two prime numbers and $n=pq$. Let $K_p=(e,n)$ and $K_s=(d,n)$ be the RSA public and private keys respectively. Recall that the encryption of a message $m$ is $c=m^e \bmod{n}$ and the decryption is $m=c^d \bmod{n}$. Which assertion is \emph{always true}?
Options: $ed=1 \pmod{n}$, $ed=1 \pmod{\varphi(n)}$, $e=d \pmod{n}$, $e=d \pmod{\varphi(n)}$
|
$ed=1 \pmod{n}$, $ed=1 \pmod{\varphi(n)}$, $e=d \pmod{n}$, $e=d \pmod{\varphi(n)}$
|
B
|
mcq_train
|
mcq_train_243
|
Question: Select the non-associative operation.
Options: $+$ (addition), $-$ (subtraction), $\times$ (multiplication), $\oplus$ (exclusive-or)
|
$+$ (addition), $-$ (subtraction), $\times$ (multiplication), $\oplus$ (exclusive-or)
|
B
|
mcq_train
|
mcq_train_244
|
Question: MD5 is
Options: a secure block cipher, a broken block cipher, a secure hash function, a broken hash function
|
a secure block cipher, a broken block cipher, a secure hash function, a broken hash function
|
D
|
mcq_train
|
mcq_train_245
|
Question: Let $N=3\cdot5\cdot13$. Then a quadratic residue in $\mathbb{Z}_N^*$ has
Options: $2$ square roots., $3$ square roots., $6$ square roots., $8$ square roots.
|
$2$ square roots., $3$ square roots., $6$ square roots., $8$ square roots.
|
D
|
mcq_train
|
mcq_train_246
|
Question: Tick the \textbf{incorrect} assertion regarding WEP and WPA2.
Options: WPA2 seems to be more secure than WEP., WPA2 seems to ensure confidentiality., WPA2 uses AES., WEP seems to ensure message integrity.
|
WPA2 seems to be more secure than WEP., WPA2 seems to ensure confidentiality., WPA2 uses AES., WEP seems to ensure message integrity.
|
D
|
mcq_train
|
mcq_train_247
|
Question: Plain RSA (with an $\ell$-bit modulus) \dots
Options: is commonly used in practice., decrypts in $O(\ell^2)$ time., encrypts in $O(\ell)$ time., has homomorphic properties.
|
is commonly used in practice., decrypts in $O(\ell^2)$ time., encrypts in $O(\ell)$ time., has homomorphic properties.
|
D
|
mcq_train
|
mcq_train_248
|
Question: Pick the \emph{correct} statement.
Options: A homomorphism is defined as a bijective isomorphism., An isomorphism is defined as a bijective homomorphism., An isomorphism is any homomorphism $h: X\rightarrow X$., A homomorphism is any non-bijective isomorphism.
|
A homomorphism is defined as a bijective isomorphism., An isomorphism is defined as a bijective homomorphism., An isomorphism is any homomorphism $h: X\rightarrow X$., A homomorphism is any non-bijective isomorphism.
|
B
|
mcq_train
|
mcq_train_249
|
Question: Which of the following elements belong to $\mathbf{Z}_{35}^*$?
Options: $12$., $20$., $14$., $15$.
|
$12$., $20$., $14$., $15$.
|
A
|
mcq_train
|
mcq_train_250
|
Question: When using the plain ElGamal cryptosystem over the group $\mathbb{Z}_p^*$ with a fixed $\ell$-bit prime $p$ and a fixed generator $g\in\mathbb{Z}_p^*$, the \textit{tightest} complexity of generating a new key-pair is\ldots
Options: $\mathcal{O}(4{\ell})$., $\mathcal{O}(\ell^3)$., $\mathcal{O}(\ell^2)$., $\mathcal{O}(\log{\ell}^4)$.
|
$\mathcal{O}(4{\ell})$., $\mathcal{O}(\ell^3)$., $\mathcal{O}(\ell^2)$., $\mathcal{O}(\log{\ell}^4)$.
|
B
|
mcq_train
|
mcq_train_251
|
Question: We represent $GF(2^8)$ as $\mathbb{Z}_2[X]/P(X)$ where $P(X) = X^8 + X^4+X^3+X+1$. Then, $(X^7+X^6)\times (X + 1)=$\dots
Options: $X^6+X^5+X^4+X^3+X$., $X^6 + X^4 + X^3 + X + 1$., $X^6$., $X^7+X^6+X^4+X^3+X+1$.
|
$X^6+X^5+X^4+X^3+X$., $X^6 + X^4 + X^3 + X + 1$., $X^6$., $X^7+X^6+X^4+X^3+X+1$.
|
B
|
mcq_train
|
mcq_train_252
|
Question: Tick the \textit{wrong} assertion.
Options: Factoring is believed to be a hard problem., Factoring is easy if we know $\varphi{(n)}$., Computing square roots in $\mathbb{Z}_n$ can be used to factor $n$., Discrete logarithm problem is always hard on any group.
|
Factoring is believed to be a hard problem., Factoring is easy if we know $\varphi{(n)}$., Computing square roots in $\mathbb{Z}_n$ can be used to factor $n$., Discrete logarithm problem is always hard on any group.
|
D
|
mcq_train
|
mcq_train_253
|
Question: Select the \emph{incorrect} statement: hash functions can be used to construct
Options: commitment schemes, key derivation functions, message authentication codes, public key cryptosystems
|
commitment schemes, key derivation functions, message authentication codes, public key cryptosystems
|
D
|
mcq_train
|
mcq_train_254
|
Question: Tick the \emph{false} assertion about Diffie and Hellman.
Options: They wrote an article entitled ``\emph{New directions in Cryptography}'' in 1976., They introduced the notion of ``\emph{trapdoor permutation}''., They proposed a key agreement protocol., They invented RSA.
|
They wrote an article entitled ``\emph{New directions in Cryptography}'' in 1976., They introduced the notion of ``\emph{trapdoor permutation}''., They proposed a key agreement protocol., They invented RSA.
|
D
|
mcq_train
|
mcq_train_255
|
Question: A hash function $h$ is collision-resistant if\dots
Options: \dots given $y$, it is hard to find $x$ such that $h(x)=y$, \dots given $x$, it is hard to find $y$ such that $h(x)=y$, \dots given $x$, it is hard to find $x' \ne x$ such that $h(x)=h(x')$, \dots it is hard to find $x,x'$ such that $x \ne x'$ and $h(x) = h(x')$
|
\dots given $y$, it is hard to find $x$ such that $h(x)=y$, \dots given $x$, it is hard to find $y$ such that $h(x)=y$, \dots given $x$, it is hard to find $x' \ne x$ such that $h(x)=h(x')$, \dots it is hard to find $x,x'$ such that $x \ne x'$ and $h(x) = h(x')$
|
D
|
mcq_train
|
mcq_train_256
|
Question: Tick the \textbf{false} statement. Bluetooth 2.0 Pairing is secure when ...
Options: the PIN has a large entropy., it is done only once., it runs in a Faraday cage., it is not used.
|
the PIN has a large entropy., it is done only once., it runs in a Faraday cage., it is not used.
|
B
|
mcq_train
|
mcq_train_257
|
Question: Bluetooth pairing v2.0 is based on\dots
Options: bilinar mappings over elliptic curves., a short authenticated string., an ephemeral secret PIN code., a secure token.
|
bilinar mappings over elliptic curves., a short authenticated string., an ephemeral secret PIN code., a secure token.
|
C
|
mcq_train
|
mcq_train_258
|
Question: The Kerckhoffs principle says that
Options: the design of a cryptosystem has to be public to be secure., the design of a cryptosystem has to be secure before being made public., the security of a system should not rely on the secrecy of the cryptosystem., a cryptosystem should have a public component (such as a key) to be secure.
|
the design of a cryptosystem has to be public to be secure., the design of a cryptosystem has to be secure before being made public., the security of a system should not rely on the secrecy of the cryptosystem., a cryptosystem should have a public component (such as a key) to be secure.
|
C
|
mcq_train
|
mcq_train_259
|
Question: A MAC forgery is\dots
Options: a valid pair $(X,c)$ produced by the adversary., a valid pair $(X,c)$ produced by the MAC issuer., a valid pair $(X,c)$ produced by the MAC verifier., a key recovery attack.
|
a valid pair $(X,c)$ produced by the adversary., a valid pair $(X,c)$ produced by the MAC issuer., a valid pair $(X,c)$ produced by the MAC verifier., a key recovery attack.
|
A
|
mcq_train
|
mcq_train_260
|
Question: Tick the \textbf{incorrect} assertion.
Options: Solving the discrete logarithm in the group $\mathbb{Z}_N$ might help breaking the Rabin cryptosystem., Solving the factoring problem might help breaking the Rabin cryptosystem., Finding square roots in $\mathbb{Z}_N$ might help breaking the Rabin cryptosystem., To decrypt properly a Rabin ciphertext we usually assume that some redundancy was added to the plaintext.
|
Solving the discrete logarithm in the group $\mathbb{Z}_N$ might help breaking the Rabin cryptosystem., Solving the factoring problem might help breaking the Rabin cryptosystem., Finding square roots in $\mathbb{Z}_N$ might help breaking the Rabin cryptosystem., To decrypt properly a Rabin ciphertext we usually assume that some redundancy was added to the plaintext.
|
A
|
mcq_train
|
mcq_train_261
|
Question: The encryption in GSM is done by ...
Options: A3., A8., E0., A5.
|
A3., A8., E0., A5.
|
D
|
mcq_train
|
mcq_train_262
|
Question: Tick the \textbf{false} statement. GSM anonymity is broken by ...
Options: replaying an A3 challenge., desynchronizing the mobile station and the network., using A5/1., sniffing the very first connection protocol.
|
replaying an A3 challenge., desynchronizing the mobile station and the network., using A5/1., sniffing the very first connection protocol.
|
C
|
mcq_train
|
mcq_train_263
|
Question: Tick the \emph{true} assertion related to the ElGamal signature scheme.
Options: A signature of a given message is obtained in a deterministic way., The generator $g$ generates a subgroup of prime order., The signature verification procedure is probabilistic., The main computational cost of the signature generation is due to one modular exponentiation.
|
A signature of a given message is obtained in a deterministic way., The generator $g$ generates a subgroup of prime order., The signature verification procedure is probabilistic., The main computational cost of the signature generation is due to one modular exponentiation.
|
D
|
mcq_train
|
mcq_train_264
|
Question: The Kerckhoff's principle is not followed when security requires that \dots
Options: the security of a cryptosystem relies on the secrecy of the encryption algorithm., the name of the cryptosystem's designer is kept secret., the key of the cryptosystem is kept secret., the cryptosystem is kept secret.
|
the security of a cryptosystem relies on the secrecy of the encryption algorithm., the name of the cryptosystem's designer is kept secret., the key of the cryptosystem is kept secret., the cryptosystem is kept secret.
|
A
|
mcq_train
|
mcq_train_265
|
Question: Tick the \emph{correct} assertion about $\mathbf{Z}_{pq}^*$, where $p$ and $q$ are distinct prime numbers \ldots
Options: the order of $\mathbf{Z}_{pq}^*$ is $p \cdot q$., an element $x$ belongs to $\mathbf{Z}_{pq}^*$ if $gcd(x,\phi(pq)) =1$., the element $1$ is in $\mathbf{Z}_{pq}^*$., the element $0$ is in $\mathbf{Z}_{pq}^*$.
|
the order of $\mathbf{Z}_{pq}^*$ is $p \cdot q$., an element $x$ belongs to $\mathbf{Z}_{pq}^*$ if $gcd(x,\phi(pq)) =1$., the element $1$ is in $\mathbf{Z}_{pq}^*$., the element $0$ is in $\mathbf{Z}_{pq}^*$.
|
C
|
mcq_train
|
mcq_train_266
|
Question: What is the inverse of 28 in $\mathbf{Z}_{77}$?
Options: $0$, $1$, $36$, $49$
|
$0$, $1$, $36$, $49$
|
D
|
mcq_train
|
mcq_train_267
|
Question: What is the time complexity to perfom a left-to-right multiplication of two $\ell$-bit integers?
Options: $\sqrt{\ell}$., $\ell $., $\ell ^2$., $\ell ^3$.
|
$\sqrt{\ell}$., $\ell $., $\ell ^2$., $\ell ^3$.
|
C
|
mcq_train
|
mcq_train_268
|
Question: Let $X$ and $K$ be two independent random variables in a group $G$ with $n$ elements and where $K$ is uniformly distributed over $G$. Let $Y = X+K$. Then, for any $y\in G$, $\Pr[Y=y]=$\dots
Options: $1/n$., $\Pr[X=y]$., $1/n^2$., $1/(n-1)$.
|
$1/n$., $\Pr[X=y]$., $1/n^2$., $1/(n-1)$.
|
A
|
mcq_train
|
mcq_train_269
|
Question: Which of these primitives can be surely considered insecure today?
Options: Symmetric key encryption with an $82$ bit key., RSA encryption scheme with a $1613$ bit modulus., A signature scheme based on a random elliptic curve over a finite field $\mathrm{GF}(q)$ of cardinality $q > 2^{200}$., Diffie-Hellman key exchange over a prime-order subgroup of $\mathbb{Z}_p^*$ that has order $\approx 2^{200}$ with a prime $p$ of $512$ bits.
|
Symmetric key encryption with an $82$ bit key., RSA encryption scheme with a $1613$ bit modulus., A signature scheme based on a random elliptic curve over a finite field $\mathrm{GF}(q)$ of cardinality $q > 2^{200}$., Diffie-Hellman key exchange over a prime-order subgroup of $\mathbb{Z}_p^*$ that has order $\approx 2^{200}$ with a prime $p$ of $512$ bits.
|
D
|
mcq_train
|
mcq_train_270
|
Question: If an adversary mounts a chosen plaintext attack, it means he can\dots
Options: do nothing except for just observing the encrypted messages on the channel., ask the participants to decrypt any messages he wants., ask the participants to encrypt any messages he wants., gain access to plaintexts corresponding to some of the observed ciphertexts.
|
do nothing except for just observing the encrypted messages on the channel., ask the participants to decrypt any messages he wants., ask the participants to encrypt any messages he wants., gain access to plaintexts corresponding to some of the observed ciphertexts.
|
C
|
mcq_train
|
mcq_train_271
|
Question: A Carmichael number \ldots
Options: is a false positive (the output is ``pseudoprime'') of Fermat test., is a false negative (the output is ``composite'') of Fermat test., always corresponds to the order of a finite field., is an exponent used in the RSA cryptosystem.
|
is a false positive (the output is ``pseudoprime'') of Fermat test., is a false negative (the output is ``composite'') of Fermat test., always corresponds to the order of a finite field., is an exponent used in the RSA cryptosystem.
|
A
|
mcq_train
|
mcq_train_272
|
Question: Select the \emph{incorrect} statement. The discrete logarithm
Options: can be solved by a polynomial algorithm., is an easy problem in the Abelian group $\mathbb{Z}_p$., is a hard problem in the multiplicative group $\mathbb{Z}_p^*$., can be solved easily on a quantum computer.
|
can be solved by a polynomial algorithm., is an easy problem in the Abelian group $\mathbb{Z}_p$., is a hard problem in the multiplicative group $\mathbb{Z}_p^*$., can be solved easily on a quantum computer.
|
A
|
mcq_train
|
mcq_train_273
|
Question: Which protocol is used for encryption in GSM?
Options: A3, A4, A5, A8
|
A3, A4, A5, A8
|
C
|
mcq_train
|
mcq_train_274
|
Question: Choose the \emph{correct} statement
Options: Elliptic curves form a field., Elliptic curves form a ring., Elliptic curves form an Abelian group., Elliptic curves form an ideal.
|
Elliptic curves form a field., Elliptic curves form a ring., Elliptic curves form an Abelian group., Elliptic curves form an ideal.
|
C
|
mcq_train
|
mcq_train_275
|
Question: Which is NOT a mobile telephony protocol?
Options: WPA, DECT, EDGE, CDMA
|
WPA, DECT, EDGE, CDMA
|
A
|
mcq_train
|
mcq_train_276
|
Question: Tick the \textbf{false} statement. Enigma ...
Options: was broken mainly because of design flaws in the patented documents., was used by the German armies in World War 2., relies on Kerchkoffs's Principle., could be plugged into a radio transmitter.
|
was broken mainly because of design flaws in the patented documents., was used by the German armies in World War 2., relies on Kerchkoffs's Principle., could be plugged into a radio transmitter.
|
A
|
mcq_train
|
mcq_train_277
|
Question: Tick the \emph{incorrect} assertion regarding the Diffie-Hellman key exchange
Options: It is secure under a passive adversary., It is secure when working in a subgroup of $\mathbb{Z}_p^*$ of big prime order., It is secure under an active Man-In-The-Middle attack., It is not secure when working in $\mathbb{Z}_n$ with $n$ having only small prime factors.
|
It is secure under a passive adversary., It is secure when working in a subgroup of $\mathbb{Z}_p^*$ of big prime order., It is secure under an active Man-In-The-Middle attack., It is not secure when working in $\mathbb{Z}_n$ with $n$ having only small prime factors.
|
C
|
mcq_train
|
mcq_train_278
|
Question: Tick the \textbf{true} statement regarding $\mathsf{GF}(2^k)$.
Options: Addition is performed as bitwise XOR., Multiplication is performed modulo $2^k$., It has order $\varphi(2^k)$., Its characteristic is $k$.
|
Addition is performed as bitwise XOR., Multiplication is performed modulo $2^k$., It has order $\varphi(2^k)$., Its characteristic is $k$.
|
A
|
mcq_train
|
mcq_train_279
|
Question: The Kerckhoffs principle states that the security of a cryptosystem should rely on the secrecy of\dots
Options: the key only, the algorithm only, the channel only, the participants' identity only
|
the key only, the algorithm only, the channel only, the participants' identity only
|
A
|
mcq_train
|
mcq_train_280
|
Question: The Tonelli algorithm is
Options: a factoring algorithm., a primality testing algorithm., an algorithm for finding square roots., an algorithm for testing quadratic residuosity.
|
a factoring algorithm., a primality testing algorithm., an algorithm for finding square roots., an algorithm for testing quadratic residuosity.
|
C
|
mcq_train
|
mcq_train_281
|
Question: Which of the following cryptographic primitives have a security level that is significantly lower than 80 bits?
Options: 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.
|
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
|
mcq_train
|
mcq_train_282
|
Question: What should the minimal length of the output of a hash function be to provide security against \emph{preimage attacks} of $2^{256}?$
Options: $2^{256}$ bits., $2^{512}$ bits., $256$ bits., $512$ bits.
|
$2^{256}$ bits., $2^{512}$ bits., $256$ bits., $512$ bits.
|
C
|
mcq_train
|
mcq_train_283
|
Question: How is data integrity ensured in WEP?
Options: there is no integrity., A3., Michael., HMAC.
|
there is no integrity., A3., Michael., HMAC.
|
A
|
mcq_train
|
mcq_train_284
|
Question: Tick the \textbf{non-commutative} operation.
Options: $+$ (addition) over $\mathbb{Z}$, $\oplus$ (exclusive-or), $-$ (subtraction) over $\mathbb{Z}$, $\times$ (multiplication) over $\mathbb{Z}$
|
$+$ (addition) over $\mathbb{Z}$, $\oplus$ (exclusive-or), $-$ (subtraction) over $\mathbb{Z}$, $\times$ (multiplication) over $\mathbb{Z}$
|
C
|
mcq_train
|
mcq_train_285
|
Question: Let $H$ be a hash function. Collision resistance means that \dots
Options: 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 $H(x_1)=H(x_2)$
|
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
|
mcq_train
|
mcq_train_286
|
Question: Select \emph{incorrect} statement. The exhaustive search
Options: 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.
|
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
|
mcq_train
|
mcq_train_287
|
Question: Choose the \emph{incorrect} statement.
Options: 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.
|
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
|
mcq_train
|
mcq_train_288
|
Question: A Carmichael number is
Options: 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.
|
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
|
mcq_train
|
mcq_train_289
|
Question: We want to generate a $\ell$-bit prime. The complexity is roughly\dots
Options: $\ell^2$, $\ell^3$, $\ell^4$, $\ell^5$
|
$\ell^2$, $\ell^3$, $\ell^4$, $\ell^5$
|
C
|
mcq_train
|
mcq_train_290
|
Question: The ElGamal cryptosystem is based on\dots
Options: nothing., the discrete logarithm problem., the RSA problem., the factorization problem.
|
nothing., the discrete logarithm problem., the RSA problem., the factorization problem.
|
B
|
mcq_train
|
mcq_train_291
|
Question: Let $E$ be an elliptic curve. Solving which of the following problems would help you to break Elliptic Curve Diffie-Hellman (ECDH) over $E$?
Options: 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 $E$.
|
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
|
mcq_train
|
mcq_train_292
|
Question: What is the encryption of the word ``SECRECY'' under the Vigen\`ere cipher using the key ``ZAB''?
Options: ``REDQEDX'', ``RDDQEDX'', ``REDQEKX'', ``REDUEDX''
|
``REDQEDX'', ``RDDQEDX'', ``REDQEKX'', ``REDUEDX''
|
A
|
mcq_train
|
mcq_train_293
|
Question: A passive adversary can \ldots
Options: do nothing., only listen to communications., only interfere with client or server communications., only replace some communication messages by others.
|
do nothing., only listen to communications., only interfere with client or server communications., only replace some communication messages by others.
|
B
|
mcq_train
|
mcq_train_294
|
Question: Let $n$ be a positive integer. The Fermat test most likely outputs ``prime'' \dots
Options: 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.
|
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
|
mcq_train
|
mcq_train_295
|
Question: When designing a cryptosystem that follows the rules of modern cryptography, we \dots
Options: 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.
|
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
|
mcq_train
|
mcq_train_296
|
Question: Which one of these digital signature schemes is \emph{not} based on the Discrete Log problem?
Options: DSA, ECDSA, Pointcheval-Vaudenay, PKCS\#1v$1.5$
|
DSA, ECDSA, Pointcheval-Vaudenay, PKCS\#1v$1.5$
|
D
|
mcq_train
|
mcq_train_297
|
Question: Tick the \textbf{incorrect} assertion.
Options: 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 to the plaintext.
|
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 to the plaintext.
|
C
|
mcq_train
|
mcq_train_298
|
Question: The result of $2^{2015} \bmod{9}$ is $\ldots$
Options: 2., 5., 4., 7.
|
2., 5., 4., 7.
|
B
|
mcq_train
|
mcq_train_299
|
Question: The complexities of the encryption and decryption in RSA with a modulus of $s$ bits are respectively within the order of magnitude \ldots
Options: $s^3$ and $s^3$, $s^4$ and $s^3$, $s^3$ and $s^4$, $s^4$ and $s^4$
|
$s^3$ and $s^3$, $s^4$ and $s^3$, $s^3$ and $s^4$, $s^4$ and $s^4$
|
A
|
mcq_train
|
mcq_train_300
|
Question: Tick the \emph{false} assumption.
Options: 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 protocol.
|
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 protocol.
|
A
|
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.