instruction stringlengths 32 27.2k |
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I am having difficulties understanding a sponge construction, as I don't really understand whether the long internal state of a sponge construction is compressed in the squeeze phase, or whether bits are extracted from it.
So like I always do with things I don't understand: I coded a simple prototype.
So is this an exa... |
For an exercise at uni I am tasked with optimizing the execution speed a chaos based image encryption algorithm 1. While I have taken an introductory class to information security, I never came accross chaos based encryption before and have been unable to find any authoratative resource explaining its significance.
Can... |
We have values in the range $[a, b]$, and we apply a differential privacy mechanism to add noise to these values. After obtaining the noisy values, we employ the following truncation function: if a noisy value falls below $a$, it is truncated to $a$, and if the noisy value exceeds $b$, it is truncated to $b$. Does this... |
I have two secure pseudorandom generators, $G_1 : S\rightarrow R, G_2 : R\rightarrow T$. Now I need to prove that the PRG $G_3(s) = G_2(G_1(s))$ is secure.
I figured that I would construct two separate attack games, and assume the existence of an adversary $A$ that can distinguish the output of $G_3$ from a truly rando... |
I read in this answer here that if the ciphertext is reasonably larger than the key size, Vigenère cipher is easily breakable.
Is there a way to repeat the key if it is reasonably smaller that the ciphertext size and be immune to statistical information leak at the same same?
I have been thinking in XORing a keystream ... |
We have a set of query answers, i.e., $A = \{A_1, A_2, \dots, A_m\}$ and then we add noise to each of $A_i$ using a mechanism ($M$) providing differential privacy, i.e., $M(A_i) = O_i$. We denote the set of noisy query answers by $O = \{O_1, O_2, \dots, O_m\}$.
Let's say an adversary is given the sets $A$ and $O$ (in s... |
p256OrdMul method in crypto/internal/nistec/p256_asm_amd64.s,
// func p256OrdMul(res, in1, in2 *p256OrdElement)
TEXT ·p256OrdMul(SB),NOSPLIT,$0
MOVQ res+0(FP), res_ptr
MOVQ in1+8(FP), x_ptr
MOVQ in2+16(FP), y_ptr
// x * y[0]
MOVQ (8*0)(y_ptr), t0
MOVQ (8*0)(x_ptr), AX
MULQ t0
MOVQ AX, a... |
Performing a key exchange with post-quantum KEMs is very different to ECDH, which will likely cause vulnerabilities in protocols during the migration to post-quantum cryptography.
One example is that different KEMs can have different binding properties, leading to re-encapsulation attacks if you're not careful.
Some le... |
Is there an easy to understand and intuitive "one fits all" definition for the concept of diffusion that is applicable to both modern binary cryptosystems as well as classical ciphers?
For a bit of background:
I am currently in the process of writing some teaching materials for high school students (~16 year olds) abou... |
I'm trying to design an encryption and decryption device that is extremely secure, but simple in design so that it can be understood and audited.
Here is my attempt, do you see any vulnerabilities?
The device consists of a keyboard, 2 LCD character displays, a SD card reader, and 3 arduinos:
The SD card has no file s... |
Say I have three 64 byte values that I hash into three sha256 hashes (H1, H2, H3). The data does not contain any secrets and it all public data. I am instead hashing the data for integrity purposes.
Now lets say I do the following:
CombinedHashesValue = H1(as bigInt) + H2(as bigInt) + H3(as bigInt)
H4 = sha256(Combine... |
I'm studying Private Information Retrieval for my class. I couldn't find any good resources online apart from various papers written on it. Can somebody recommend a textbook, lecture or any other good resources for Private Information Retrieval?
|
I am reading about GKR protocol from Justin Thaler's book - Proofs, Arguments & Zero Knowledge
On Page 59,
In the first message, $P$ tells $V$ the (claimed) output(s) of the circuit. The protocol then works its way in iterations towards the input layer, with one iteration devoted to each layer.
I am a little confused... |
Does there exist a proof (paper reference welcome) that if a signature scheme is EUF-CMA, and the signatures are always encrypted, then the resulting signature scheme is SUF-CMA?
That is: let SIG be an EUF-CMA signature scheme. Then SIG' is defined as follows:
s = SIG(secret key, message)
c = ENC(K, s) where ENC is a ... |
I used an open-source programming language called Lucee / Cfscript that is closely related to Adobe Coldfusion. The default function that developers use to encrypt and decrypt data (usually for passwords or cookie contents etc) is meant to be compatible with a version of Coldfusion that released in 2002. Given that the... |
Imagine an Encryption Algorithm which applies a classic Shift Cipher (also called Caesar or ROT-X) to a text (with only lowercase [a-z] and the space ' ' character), but has one parameter r (randomness) to decide if in each round/iteration attempting to encrypt one char c, it encrypts the character c+key, or if it inse... |
I am designing a service where each user has both a unique 256-bit private and public ID. These IDs should be derivable from one another, but only within the backend of my service (as to not expose the private IDs to other users). For this purpose, I am considering using AES with a key known only by my service, but thi... |
I was reviewing past exam questions and came across this one:
Is it secure for A (the garbler) to allow B (the evaluator) to
run a garbled circuit twice with different inputs? They
aim to compute the output of a function F for two pairs of inputs,
A encrypts the circuit and sends the garbled
circuit to B. B also recei... |
I'm studying for an exam and came across this question:
When an electronic signature of a message claimed to be produced by
Alice is verified we typically verify (at least the first time):
that the public key belongs to Alice by verifying that it has been signed (along with additional information) by a certificate au... |
I know Signal uses public/private key E2E encryption to ensure it's impossible for them to read the contents of messages. WhatsApp does too, hence Signal's main attraction is that it additionally claims to avoid collecting metadata pertaining to the messages (unlike WhatsApp). Their server code, last time I checked, ... |
I have two statements which I think are correct:
$\beta, s$ are unknown.
Only $g^\beta$ is known to the prover but not any of $g^{\beta s^i}$ for $i \ge 1$.
If the prover is able to find group elements $A$ and $B$ such that $e(A, g^\beta) = e(B, g)$ then the prover knows a field element $a$ such that $A = g^a$
And a ... |
Does anybody have a library of fastest parity finding algorithms in RNS representation? By parity I mean $x \bmod 2$ where $x$ is the number between $0$ and $N=\Pi m_i$ and all moduli are odd.
I have found a fast algorithm, but since it is quite simple, I need to check whether it pre-exists or not. I found a reference ... |
Given that an algorithmic implementation of a linear feedback shift register based encryption scheme is (much?) more secure against side channel attacks; why are hardware platforms usually used?
I get that speed is a factor in stream/block cipher systems used in communication protocols ie. error correction or encryptio... |
This is related to Is it possible to create a mix of predefined and generated shares for Shamir's Secret Sharing?, but I have unfortunately lost access to that question and can't merge accounts right now.
I now know that it is most definitely possible to create some predefined shares but was looking for further informa... |
Why was the simulator/extractor specifically given the power to rewind "time" instead of a different super power?
Was it defined in the first ZKP paper that the simulator and extractor would have this power as a "standard" and then everyone went with it or was there more thought put into it when giving it this super po... |
Consider a standard supervised machine learning problem on private data. Instead of using DPSGD, suppose that one uses a non-private SGD scheme to produce optimal model parameters $\theta$ (done in the private data enclave, as with DPSGD), and releases publicly $\theta + \eta$, with $\eta \sim$ Laplace$(0, \varepsilon)... |
There is a lot of confusing information out there regarding the role of digital certificates and the use of Ephimeral Diffie Hellman in how TLS 1.3 operates.
Would it be correct to state that the the digital certificate signed by the CA is only used by the client to verify that it is connected to the correct server ? T... |
i'm new to information theory.
I know the standard perfect secrecy definition:
$$
P(M=m|C=c) = P(M=m) ,
$$
for all $m$ and $c$, respectively the message and the cypher.
Now, i can use the entropic definitions to conclude that if the above equation holds, also the following is true:
$$
H(M|C)=H(M) ,
$$
right?
But is it ... |
Im reviewing my crypto and I would like to prove the following: RSA experiment where the adversary is given N, e, and y. The adversary knows p, q.
I know the RSA scheme is built on the idea that it is hard to find 2 large primes that are factors of N, and we already have this so it's easy to solve for d now. In order t... |
First time question poster so I hope the below is clear enough :).
Problem summary: Can a Holder and Verifier safely use ECDH for a Challenge-Response protocol where:
the Holder proves possession and control over a private key $d$ using material that a trusted Issuer signs, and
the Verifier learns no correlation handl... |
I have a wireless capture of data and it's 12 bit hash. I am trying to identify the actual function that would have generated the hash data.
I tried all the generic 12 bit CRC polynomials but none of them seem to generate the appropriate output.
Any ideas on how I could reverse engineer the hash function?
Here's the in... |
This has probably been asked before but for a given ciphertext and plaintext pair, is it possible to have two different keys producing said pair? Or there are no collisions in AES, unlike hashing algorithms such as SHA1, SHA256, etc?
|
I have code where someone made the key 64 bytes (32*2) and passes to the derive_key() function. It then uses the key created for aes_encrypt_key256() which would only use 32 bytes.
Is there any good reason why the code is doing that vs just using a 32 byte key that is passed to derive_key() ?
TIA!!
|
I know next to nothing about cryptography. From what I have understood, anything that is provable can be done so using a zero knowledge proof (the result seems to be known from the 1980's or so, by S. Micali & al.)
Starting from a given chess position, I want to use zero knowledge proof for a Prover to convince a Verif... |
What does it mean when we say something like „we need more than polynomial time many cipher texts“? I understand it as „an adversarial can run for polynomial time and try as many messages as possible in an exhaustive search on our encoded message in this time. We need more messages than the maximum the adversarial can ... |
I am exploring the implementation of a cryptographic signature that users can manually input, and I am willing to compromise security to a level where a hacker investing several thousand dollars in hardware can potentially crack it!
From my research, BLS seems suitable, but the standard signature size is too large for ... |
The question I'm wondering is whether the AES cipher is a closed cipher (which is equivalent to AES being a group). And this question interests me due to the lack of understanding of whether it is possible to encrypt using the AES algorithm with two different keys and hope for increased strength, as for example in 3DES... |
Let us recall the Schnorr Protocol, following Chris Peikert's excellent Notes on the Theory of Cryptography.
Protocol. Let $G=\langle g \rangle$ be a cyclic group of order $q$. We consider an arbitrary element $x\in G$, having Discrete Logarithm $w=:\log_g(x)$. The input to the Prover $P$ is $x,w$ and to the Verifier $... |
Let's assume that the password to be cracked is 15 characters long and consists of numbers (to keep the math simple). Let's assume the attacker has the following information about the password:
It is at least 8 characters long
It consists of numbers.
It is random
What is the maximum number of combinations the attacke... |
I have this uni project that I have to implement in code:
"App for Secure delivery of the gray images, encryption-decryption with AES in OFB mode + secret key delivery using Merkle–Hellman knapsack + DSA signature"
I am struggling with structure of the program and how to combine these algorithms together.
What I did s... |
I tried to understand how dense the Mod-LWR samples are in some space. I tried to see from a view similar to LWE, i.e. using GV-bound(maybe LPN is better example because GV-bound is for codes). But I have some difficulties with the parameters.
Take the Mod-LWR samples used in Saber as example:
If the maximum number of ... |
Given a private key using algorithm RSA-PSS with SHA256 is it possible to use this key to sign a JWT using algorith RS256 (RSA with SHA256) instead of PS256 (RSA-PSS with SHA256)?
The German government seems to be of the opinion it is possible and wants us to do this for one of their new tax reporting related APIs.
So ... |
Assume the discrete log problem:
$g^x mod (p) = h$
For sure, $p$ is a prime number and $g$ is its primitive root or generator and assume that Alice sent $h$ to Bob and middle man caught it. So attacker knows $g, p, h$ and wants to find $x$.
One solution is for the attacker to try all possible values. The modular expone... |
Basically the same question as this one, except in my case the value to be hashed doesn’t have to be a valid Bitcoin block, but is a bytearray of arbitrary length and content (and that my use case is completely unrelated to Bitcoin).
In details, I have to deal with a computation that does x^ ((Integer)sha256(y)&0x7ffff... |
In the eliptic curve cryptography, we use modulus $y^2 = (x^3 + ax + b) \ \ \text{mod} \ \ p$
So using modulus definitely changes the graph points completely - i.e gives a completely different graph than $y^2 = x^3 + ax + b$ would give.
What's the easy explanation of why we use modulus ? In Diffie-Hellman, I understand... |
I’ve a signature system using modular exponentiation where having the exponent being a composite with a known factor allows to forge signatures…
In order to check if the exponent is a prime number, the Integer has to pass 27 rounds of miller‑rabin (though with always using the same base) : if it is found to be composit... |
I'm helping a company to redesign their cryptographic protocol for communication within a network of embedded devices.
So far I have discovered several insecure practices, such as using very short (6 characters) passwords to derive AES symmetric keys and so on.
When redesigning the protocol, I wanted to use stream ciph... |
I'm trying to better understand RSA. One attack I've read about is when the encrypted message $y$ and $N = p\cdot q$ share a common factor. If this happens, we can easily factor $N$ to obtain $p$ and $q$.
What are some strategies that can mitigate this potential issue?
|
I am trying to obtain the reciprocal of a floating point value $x$ using the Chebyshev approximation, where $x$ is mostly in the order of $10^3$ to $10^5$. Subsequently, I am trying to implement that algorithm using CKKS for secure computation. My initial attempt with Taylor's series didn't help me that much due to acc... |
I've recently read part of a book exploring secure data deletion techniques for many storage mediums. In particular, I read about assured data deletion techniques developed for data outsourced to the cloud. Many of the alternatives are based on cryptographic techniques using symmetric encryption to encrypt data and som... |
Yao introduced a famous notion of securely computing any function between 2 users using a concept of Garbling circuit. How can this idea be extended for n-party case? That is there are n-1 garblers and 1 evaluator.
How is the security of n-party garbled circuit defined? When is it useful?
|
I am looking at ways to blind an ECDSA signing key (and verification key respectively).
Looking at proposed solutions like the IETF KBSS draft, and the IETF ARKG draft it seems that the ECDSA key blinding requires a multiplicative blinding with a blinding value $b$ that cannot be controlled by an attacker (and I assume... |
RSA can't be used securely as is as it is deterministic. So an encrypted "yes" always looks the same. A simple workaround, which is apparently not secure, is to add 100 bits, say, of random salt to your plaintext before encryption. Why is this not considered secure?
|
I have read
[1]Decentralized Multi-authority ABE for NC1 from BDH,
[2]Decentralizing Attribute-Based Encryption,
[3]Fully Adaptive Decentralized Multi-Authority ABE,
When I compare security proof in [3](full adaptive), I find out that when construct hybrid games, authors do not rely on public and private keys generated... |
The output of command fortune | gpg -vaer <receipent-id> has a line that begins with:
gpg: RSA/AES256.CFB encrypted for ...
What is AES256.CFB doing here when the key is a RSA key? Isn't the data supposed to be encrypted with RSA given this is public key cryptography?
|
I am asking it again because no one answered my previous question with more clarity. I have deleted that question
One more co-CDH in Type three pairing groups $G_1 \times G_2 \to G_T$: means given a generator $g_2$ in $G_2$, $A = g_2^a$ with random $a$ and an oracle $\mathcal{O}$ which which accepts query $Q \in G_1$ a... |
Forgive my ignorance, but I've run into some confusion in an AES implementation I'm testing.
To the best of my understanding, ECB provides no diffusion, the same plaintext with the same key will yield the same ciphertext every time. That's what makes it so bad for real-world cryptography.
But as a programmer, my curren... |
Let's say we have a billion short individual json files with same regular structure: {"name": "<name>", "id": <id>}. Each file is individually encrypted with some crypto algorithm (symmetric or asymmetric). The cryptanalyst has all the billion files, and additionally knows public key that generated the billion individu... |
I have read lots of books about CPA,CCA1,CCA2. I understand how to get an example satisfies CPA but not CCA2. However, I can't find such a scheme which is CPA but not CCA1. What is the extra advantage by lunch attack?
|
the gnfs is the most efficient algorithm for factoring numbers formed of equal composites.
But it’s sequential/Linea Algebra parts mean (If I’m not wrong), that it requires at least 10 minutes on current hardware to factor semi‑primes formed of composites of equal length (in the case of 382 bits semi‑primes).
Are there... |
I am trying to implement the NTT as done in this paper, but I keep getting the wrong result even when doing the math by hand. Is formula 9 of the paper wrong ? (I suspect that I am the wrong one but just want to confirm)
|
Two popular example dynamical systems for PRNG are
LFSRs, basically the orbit $(x^ks)_{k>0}$ for some non-zero seed $s$ and (primitive) $x$ in $GF(2^n)^{\times}$
CTR_DRBG, say with AES128 and 256-bit seed covering the key and initial counter block (i.e. $N+2$ AES encryptions, $N$ for output and one each for updating ... |
When I'm reading this paper "On lattices, learning with errors, random linear codes, and cryptography" by O. Regev. I have trouble understanding the proof of claim 5.2.
"Hence, it is enough to show that $\left|\sum_{i=1}^k p x_i \bmod p\right|<p / 16$ with high probability. This condition is equivalent to the condition... |
Root (Hash01234)
/ \
Hash0123 Hash4
/ \
Hash01 Hash23
/ \ / \
Hash0 Hash1 Hash2 Hash3
Can I construct a Merkle Tree like above instead of creating it like the below?
Root ... |
Let's say a user creates their primary gpg key pair for User Name <user@email.com> and selects an encryption and signing algorithm that isn't widely available (think goldilocks). For instance, let's say one would create a signing key with ed448, and encryption key with cv448.
If the user goes ahead and submits such a k... |
In question (1.b) in Homework 10 for Brown University's Cryptography course, they present the problem of providing a zero-knowledge proof for $L = \{ ((G_0, G_1), (G'_0, G'_1)) \mid G_0 \cong G_1 \vee G'_0 \cong G'_1 \}$
It’s trivial to show that since it is an NP language then there is a zero-knowledge proof, but I th... |
Consider a model of computation where we have a public oracle that provides access to a random sequence $R$. Given an index $i$ the oracle returns either 0 or 1, with the responses being deterministic, but the response for $i$ independent of $i+1$. Intuitively you can think of the oracle as providing access to "shared ... |
The idea of n-1 parties being garblers and 1 party being evaluator is not clear to me. Can I get an explanation of how the BMR protocol runs stage by stage with an example.
I guess the keys to each wire is concatenation of the keys from every garbler, however what's the need for permutation bit?
How is the security of... |
I'm doing a project for my Data security course, and it's to implement the HillCipher Algorithm in C#.I've successfully Implemented the Encryption and Decryption.
however there is one function missing and it's the Analyse function which takes the Plaintext and the Ciphertext and it should return the Key I know that the... |
Is it possible to construct an efficient-to-compute function $F: X \rightarrow Y$ such that
Given samples $(x_1, F(x_1))...(x_n, F(x_n))$, any efficient adversary ($F$ itself is kept secret) can't figure out $F(x)$ for a new $x \neq x_i$.
The function $F$ preserves locality in a sense that, for some constant $L$ and n... |
Adaptive adversaries are a class of adversaries who can decide to corrupt parties in the protocol execution process. However, I want more information about this model and the proof skills. There are some questions:
(1) Where can I find the corresponding security definition? When was it first proposed and by whom?
(2) A... |
Let $p$ be the prime number 115792089237316195423570985008687907853269984665640564039457584007908834671663
and let $E$ and $E'$ be the curve equations
$$E(\mathbb F_{p^6}) : x^3 + 7$$
$$E'(\mathbb F_{p^6}) : x^3 + 4$$
then, by sextic twist property, $E/\mathbb F_{p^6}$ and $E'/\mathbb F_{p^6}$ are isomorphic.
How shoul... |
Let us consider the scenario where there are n-1 garblers and a single evaluator. The garblers together need to generate a garbled circuit. We use a distributed garbling protocol such as [BLO16] and hand over the inputs to evaluator.
Why during the computation are the masking bits needed? It is stated that each party ... |
Is there any example for data that has the same sha256sum value?
Or is it impossible to find out with current computational power?
|
I have difficulties understanding the PRP in the absorb phase of a sponge construction: a block is XORed to the r part of the state memory,and then the entire state sent through a blockcipher-like pseudorrandom permutation in CBC-Mode or is it simply seen as an output of a pseudorrandom function f or can you do both?
I... |
When assuming the following idea for ciphers:
For a block cipher, a 4-round balanced Feistel network where the PRF is BLAKE3 and the key schedule is: input key, input key with every odd bit flipped, input key with every even bit flipped, input key with every bit flipped.
For a stream cipher: a 64-bit unsigned int that ... |
There are MPC comparison protocols which can securely compute $(a<^?0):=\begin{cases}1,\text{ if }a<0\\ 0,\text{ otherwise}\end{cases}$, where $a$ is an element of a prime-order field (of course one needs a notion of what $"<"$ even means in this case). But to my knowledge, all of them use some kind of bit decompositio... |
Simple question : given a randomly generated number $N$ from a hash that is hard to factor, how to check if $N$ is probably a semi‑prime in a faster way than factoring it ?
My problem is while it’s easy to check if $N$ has more than 2 composites most of the time, I’d like to avoid scenarios where I spend 9 months to di... |
Assuming the generator of one group $\mathbb G$ is $G$. Given an element $C\in \mathbb G$ and a cryptographic hash function $H(\cdot)$, is it hard for one adversary to find a pair of message $m$ and another element $R\in \mathbb G$ to make $RG^{H(m||R)}=C$?
Besides, is it necessary to make $H(\cdot)$ become the random ... |
Are the rogue key attack and the key cancellation attack identical within digital multi signature? In both cases the attacker generates a valid signature instead of other cosigners, to my understanding.
|
From this answer I am able to understand that if CM field discriminant for a particular curve is small then it provide us a fast endomorphism which in turn allow rho method to speed up by $\sqrt{\frac{1}{3}}$.
What I cannot understand is:
How one calculate this CM discriminant? Is this same as $\Delta = 4a^3 + 27b^2$ ... |
Over a few days, I have been trying to understand the FRI protocol discussed in the link https://aszepieniec.github.io/stark-anatomy/fri . It explains Fast Reed-Solomon Interactive Oracle Proof (FRI) protocol using merkle tree polynomial commitment. This protocol is run between a prover and verifier. To enhance my unde... |
Hypothetically, if I am using tink-java and I generate a keyset/keypair. If I lost my public key, can I get the public key from the private key?
|
The security of the multi-party computation protocol can be given by real/ideal world paradigm. The simulator based proof considers the joint distribution of adversary's output and honest parties output.
Why is there a need to take the joint distribution in this case? Why can't we just take adversary's output to prove ... |
I read a statement that states OT (Oblivious transfers) cannot be constructed from public key encryption in a black box manner.
What does it mean here by black box manner? Is Oblivious transfer a complete primitive?
|
I'm building a micro-controller based encryption device that uses one time pads. System details
The reason I'm going this route is that I want a system which secure, but also very simple and easy to understand.
One time pad encryption has a known vulnerability against bit flip attacks. I would like to mitigate this ris... |
I'm looking for a more efficient way to avoid adding duplicate members to a cryptographic accumulator.
Currently, I require users to provide a non-membership proof, and only if the proof is valid, adding to the accumulator is allowed.
Is there a way to merge the check-and-add steps into one step?
Additionally, I've not... |
I have case when I need take payload to client with key for decrypting. But client mustn't encrypt another payload by this key.
After some research, as I understand it's case of asymmetric encryption.
Me: Encrypt data by "public" key.
Client: Decrypts data by "private" key and can't encrypt another payload because he d... |
NIST recently unveiled the criteria for crafting a new block cipher mode of operation for AES called Accordion Cipher Mode. Simultaneously, they've announced Ascon as the Winner in the Lightweight Cryptography competition (LWC). This raises the question:
What shortcomings does Ascon possess, prompting NIST to convene ... |
According to answer and status of PGP on RFC search, OpenPGP RFCs can be used as "technical reference for the applicable internet standard". The quote mentioned in previous sentence is a little vague. In Crypto community, is OpenPGP widely accepted as a standard? Would anyone know what is holding OpenPGP's status to be... |
I checked a related question, but I still did not find the answer I was looking for.
Specifically, do we have any statistics on the usage of DES/2DES/3DES?
It seems from here that credit card systems are relying on 3DES. Is this still the case?
Also, I guess that many old satellites are still relying on some DES for th... |
I wrote a simple implementation of ChaCha20 encryptor for files in C using MbedTLS implementation. The process of encryption is standard - I set key, then for each block of fixed size I generate new nonce (to prevent nonce reuse) and encrypt this block. Then I write nonce to a new file and then append block of encrypte... |
EdDSA generates the private nonce deterministically by hashing the private key and the message, and this means that the public nonce $r$ and the signature s will be same if the same message signed more than once.
Does this mean that EdDSA is vulnerable to replay attacks? I know it is not, but I don't know what the mech... |
I am looking for a square matrix whose determinant is 0, however, all sub-minors of this matrix are non singular. This matrix needs to have applications in Cryptography. The matrix may be over any Galois field of type 2^r. Please provide an example and references. Thank you.
|
I have been reading Flaws in Applying Proof Methodologies to Signature Schemes and ran into a bit I do not understand.
In section 4.2 the authors describe a scheme where a malicious signer crafts a public key and signature that verifies two different messages. They postulate that upon revealing the second message the p... |
We utilize a differential privacy mechanism (Laplace noise, with scale $b$) to provide the privacy of records stored within a dataset. Each individual is associated with two, and at most $k$, records. These records are represented as $(\textsf{Username}, O_i)$, where $O_i$ denotes the $i$th noisy value (generated by th... |
If I have $n$ secure assymetric encryption schemes, is their concatenation $Enc_{k_1,...,k_n}(m)=Enc_{k_1}(m)||...||Enc_{k_n}(m)$ secure?
My intuition is that the concatenation is secure, but I can't solve it by reduction, which gives me the feeling that maybe an attacker can somehow take advantage of the combination o... |
I'm wondering if anyone is aware of the best input difference to input into the system Heys outlines in his paper (http://www.cs.bc.edu/~straubin/crypto2017/heys.pdf) to achieve a high probability differential characteristic w/ S-Box 4_1 and S_Box 4_3 active at the point of attack (4_2 and 4_4 inactive). I've built a f... |
This question may seem related to this one, but it is not the same.
Let's suppose I take 1GiB of data, encrypt the data with a (secure) block cipher and apply the Vigenère key, being the key much smaller than the ciphertext data (let's say, 512KiB), repeating the key hundreds/thousands of times over the plaintext.
In t... |
I know that in groups from large prime order the discrete log problem is considered hard. For example, it is hard to compute $x$ from $g^x$ and $g$.
Does the same holds for the root problem? For example, is it hard in such groups to compute $g$ from $g^x$ and $x$?
|
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