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Please see the Reference section below for terms.
Is there a known one-way method to produce an array of indexes, based only on two input elements:
length of the resulting array
number, used as a key to deterministically produce the array
If there exists only a method that can produce only fixed-length arrays - it ca... |
Why randomness space must be significantly larger than the commitment space |R|>|C|? the picture is from https://youtu.be/IkNZWJFcfcU?t=236
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While creating secret keys in IKE protocol, sides use cookies but I did not understand where they come from, how they are generated and why they are used. Can someone explain? Thanks.
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I'm working with SWIFFT, a provably secure keyed hash function, which is desirable to me. Unfortunately from what I gather it is ONLY a keyed hash function. Would there be any disadvantages or security problems if I just gave everyone the key and used perhaps public key encryption to do the authentication "manually", u... |
Suppose I have a real physical dictionary, and I want to draw words from it randomly, using dices. How should I do it?
Maybe it's easier to work with a coin since it's easier to convert binary to a decimal, but whatever, if I use dice, then I can generate a number in base 6 with some dice throws.
The problem is that th... |
In Gentry's seminal paper on fully homomorphic encryption (FHE), it is assumed that the sparse subset set problem is hard. It looks like there is a followup paper on the concrete parameter of the subset size, which mentions that Gentry's choice of subset size is too aggressive (e.g., 15). However, in its section 5 (Dis... |
So I was reading about 1-bit error propagation for AES mode and how it propagates in various modes. I was wondering how error would propagate in ECB, CBC and CTR modes if it was a 2-bit or a 3-bit error on the ciphertext block when the receiver decrypts the ciphertext?
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In IKE exchanges, first messages sent unencrypted and unauthenticated. For authentication, messages sent encrypted with nonces.
If a man in the middle is eavesdropping this conversation, he/she will know which encryption algorithm will be used in exchanges. Can't the attacker know contents of every encrypted messages b... |
In TLS 1.3, handshake messages (except for ClientHello and ServerHello) are protected by keys derived from the handshake secret. After the handshake completes, master secret is derived from the handshake secret, which is then used to derive keying material for application messages.
Why are handshake and master secrets ... |
What's the meaning of Apostrophe over a variable in the context conversations of verification?
Reference number: https://people.eecs.berkeley.edu/~jfc/'mender/IEEESP02.pdf
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I was going through Signal's Double Ratchet algorithm specification, and they mention that the DH ratchet step is done for every message.
I'm curious what happens if you only ratchet 1 every X messages? Specifically, what info would be leaked to an eavesdropper, and could the the protocol be adapted to handle this.
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In cryptography, padding is any of a number of distinct practices
which all include adding data to the beginning, middle, or end of a
message prior to encryption. In classical cryptography, padding may
include adding nonsense phrases to a message to obscure the fact that
many messages end in predictable ways.
Checksu... |
I was reading this paper by Philippe Golle on using the homomorphic properties of ElGamal encryption to play a game of mental poker (i.e. cryptographically secure poker without a trusted third party dealer). I decided that it would be a good project to try to implement some basic version of but I quickly ran into some ... |
Are there any cryptographic methods $f,g,h$ which can be applied in any order to an input $x$ while still resulting in the same result $r$:
$$f(g(h(x)))=h(g(f(x)))=ghf(x)=fhg(x)=hfg(x)=gfh(x) = r$$
Same for their inverse function:
$$f^{-1}(g^{-1}(h^{-1}(r)))=h^{-1}(g^{-1}(f^{-1}(r)))=g^{-1}(h^{-1}(f^{-1}(r))) =...= x$$... |
Suppose two signature schemes provides the same level of security. The sum of the sizes of a public key and a signature, i.e., sizeof(sig) + sizeof(pk), are equal in the two schemes. One of the schemes has smaller public key size, and the other has smaller signature size. Then which scheme is preferred in practice? If ... |
WhatsApp has taken the step of using the Open Whisper Protocol for their message encryption, borrowed from the Signal application.
I was wondering if there was any obvious, high level, difference in the implementation of the Open Whisper Protocol between these two mobile phone applications? For example, Perhaps Signal ... |
CCM mode refers to CTR+ CBC-MAC encryption mode.
Based on this paper, the adversary's advantages against the authenticity of CCM is:
Eq(1)
Authenticity: it should be infeasible for an adversary to forge a valid ciphertext without knowing the secret key.
and the adversary's advantage against the privacy of CCM is:
Eq(2... |
In the case of a OTP (One Time Pad), if we encrypt two different images with the same key, then two encrypted images will be generated. Then if these two encrypted images are mixed with bitwise xor ⊕, then the traces of the two original images are revealed.
On the other hand in a hypothetical MTP (Many Time Pad) stream... |
If we have a secure PRF (, ) and a PRG G where : → × is a secure PRG.
Is the PRF F'(k, x) = = ((, )) also secure?
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Assuming that all other elements like the internal state of the algorithm are considered secured and very hard to discover from a cryptanalytic standpoint.
How significant would be for the algorithm to be able to pass the PractRand with the specifications mentioned?
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I am looking for ways to securely sort two lists of numbers. Yao's millionaire's problem considers each party with one secrete number and compare them securely. Are there papers on extension to this problem where each party has one list of numbers and each party will learn the positions of each element of its list with... |
Game:
Users stack blocks to form an unstable tower. Each time a new block is successfully laid, the game creates a score_string which is meant as proof of the user's current score. Assume each user has a unique public key that is known to the leaderboard, and that the user can sign their score_string when submitting to... |
I am learning about collision resistance security notion of hash functions. However, I got confused when collision resistance experiment started using "keyed" hash functions in the experiment (and also in other similar experiments). This is a small extract from Introduction to Modern Cryptography by Katz and Lindell :
... |
Is following RSA signature scheme secure against forgery and prevents breaking text book RSA?
$$y = \operatorname{SHA-256}(m)$$
$$s = y^d\bmod N$$
where $m$ is message of arbitrary length, $y$ is the 256-bit hash of $m$ computed using SHA-256, $d$ is RSA private key, and $N$ is an RSA modulus with length 2048 or higher... |
Suppose that a set of entities each have public/private key pairs, (P1, S1), (P2, S2), ..., (Pn, Sn).
In a straightforward scenario, a message signed with Si can be verified using Pi.
My question is, is there a way for me to sign a message with {S1...Sn} and the signature can be verified using one of the {P1...Pn}?
Her... |
I would like convert between one bech32 address to another with different slip44 coinTypes.
For example, a terra address terra172xqaafhz6djy448p32633q4rl7eaz4wqnjn46 uses slip44=330 and cosmos address cosmos1mwwvfu804wcaanz8j78f8h75flxkyjua23kdvw uses slip44=118.
The prefixes can be assume to be the first characters ti... |
I have been studying Zero Knowledge Proof. I found the Definition of Interactive Proof says that Verifier is ppt.
And I only found in PP (Complexity) Wikipedia says that ppt:
Turing machines that are polynomially-bound and probabilistic are
characterized as PPT, which stands for probabilistic polynomial-time
machines.... |
I am working on a hardware security problem. It involves authentication of contents of a packet header at the network-on-chip level, which is very resource constrained in nature. I have a Pearson Hash of the header contents, which I would like to digitally sign so that it can be verified by other nodes of the network t... |
Testing a code that uses the Camellia 1.2.0 source code, when generating a keyTable from the input key, using:
void Camellia_Ekeygen(const int keyBitLength,
const unsigned char *rawKey,
KEY_TABLE_TYPE keyTable)
The output shows a few 'zeroed' words at the same places. Two random examples for 256 ... |
A cyclic sequence can be produced with
$$s_{i+1} = s_i^a \mod N$$
with $N = P \cdot Q$ and $P = 2\cdot p+1$ and $Q = 2\cdot q+1$ with $P,Q,p,q$ primes.
and $a$ a primitive root of $p$ and $q$.
The starting point $s_0$ is a square ($\mod N$)
It will produce a cycle of length $\mathrm{lcm}(p-1.q-1)$
(except $s_0$ is a ... |
I have been doing some research in group and ring signature literature for anonymous signatures. I am trying to find a group signature scheme which provide the following proprieties:
Anonymity for the signer
The signature can be verified by a generic receiver
Output just one signature (I do not want a kind of LSAG Sig... |
Hello I am quite new in cryptography so I found Trivium stream cipher can anyone explain in basic language how Trivium cipher works
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I'm trying to figure out how to construct an extractor for a non-interactive lattice-based proof. Specifically, I'm curious about the Fiat-Shamir transform applied to a five-move interactive protocol. Can you please explain to me what strategy should be used? Or share a link to an article with examples (references to e... |
The well known Decisional Diffie Hellman assumption (DDH) assert that for any $n = \log q$ and generator $g$ of $\mathbb{Z}_q$, for uniformly i.i.d $A, B, C \sim U(\mathbb{Z}_q)$, the following are indistinguishable for any PPT $M$: $g^A, g^B, g^C$ vs. $g^A, g^B, g^{AB}$. That is, up to negligible advantage:
$$\epsilon... |
Consider a variant of DES algorithm, called DES-WEAK. In DES-WEAK,
there is no permutation P in a round and all the S-boxes are replaced. The new S-boxes are all
identical and defined as follows. Let b0, . . ., b5 represent the six input bits to an S-box and a0,
a1, a2, and a3 the four output bits. Then, a0 = b3 ⊕ b0b1... |
The PKCS#7 padding is defined in rfc5652#section-6.3
Some content-encryption algorithms assume the input length is a
multiple of k octets, where k is greater than one. For such
algorithms, the input shall be padded at the trailing end with
k-(lth mod k) octets all having value k-(lth mod k), where lth is
the length o... |
The BFV scheme is good for representing lots of integers inside a polynomial and we can even operate on them individually relatively fast. However, bootstrapping on BFV is infeasible, such that no library even implements it.
On the other hand, schemes like TFHE have very fast bootstrapping, but operate on gates. This p... |
As I understand, the Bitcoin network can be seen as a supercomputer looking for SHA256 collisions. It hasn't found one yet (March 2022). Also, in the post-quantum cryptography era, you would be capable of reversing SHA256 hashes.
But in the case of finding hash collisions, is there an algorithm already proposed?
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My understanding was that SHA-256 is pretty random or "random" enough.
I assumed that would mean that every character would behave like a 1 to 16 dice roll.
With this assumption, I would expect that you can model the probability of repeating characters as $16^x$. So a chain of $\texttt{FFF}$ or $\texttt{333}$ would hav... |
Multiple Encryption For Multi-Key Security
I have a hypothetical question about multiple encryption after reading Matthew Green’s blog on multiple encryption. For those who are familiar with GCM…I want to understand the efficacy of multi-key security through an implementation of multiple encryption with a secure form o... |
In game-based security proof for key-exchange protocols, there is a Test query. The Test(U) query typically is only available to the adversary if the attacked instance U is fresh. (U represents either a participant or an oracle)
Fresh: Before the session expires, there is no SSReveal(U), SKReveal(U) or Corrupt(U) query... |
Calculating the RC5 encrypted size of any data is as simple as rounding up the plaintext length to the nearest multiple of 8. What I'm wondering is whether this can be done in the other direction, to get the length of the original plaintext data given the ciphertext. Obviously this information isn't revealed until the ... |
I have this definition:
each ciphertext is equally probable for a given plaintext and key
chosen at random
I know that perfect security can be defined as
$$\forall c \in \mathcal{C} \ \forall m_1,m_2\in \mathcal{M} \ Pr[Enc_k(m_1)=c \ for \ k \ random]=Pr[Enc_k(m_2)=c \ for \ key \ random]$$
Are these equivalent?
The... |
I'm learning about Shor's algorithm and how it can be applied to break ECDSA. I've clearly missed something basic here - I thought I understood that the challenge ECDSA presented was to find the private key given the public key, as follows:
$x\cdot P = X$ (where $x$ is the large and randomly-generated private key, $P$ ... |
Suppose that we play the game from Adversarial Indistinguishability but adversarial can choose three messages $m_0, m_1, m_2$. Of course, $Pr[M=m_i]=1/3$ for $i=0,1,2$. I suppose that to have adversarial indistinguishability, one cannot have an advantage greater than $1/3$. The question is if this is stronger than the ... |
I have tested out with a few test cases, it seemed like the ciphertext $M^e$ of RSA is always coprime with N when e=3. Is there a reason why? What would happen if the ciphertext $M^e$ is not coprime with M when e=3?
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Mathematically is it possible to find the GCD of two points on a prime curve, one of them not being the order as you do in Extended Euclidean Algorithm?
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I read few answers about the question: why are hash collisions so dangerous?
But did not get a really satisfying answer.
Assume we are the first people who found a SHA256-collision, like
sha256($§"%fa7asd8ft6sds) = sha256(889=?`/&&%"HSF)
(this is not a real equation, but assume it is true).
Why is this dangerous? Why i... |
I am new to the simulated proof and am a little bit confused about the abort in the simulation.
When the real-time protocol abort, I assume that the ideal process should also abort? Does this mean that the simulator would first observe the result of real-time protocol, then decides what to run to reach abortion?
Sorry,... |
I want to design a scheme, where there is a circuit C0 which is obscured by an indistinguishability obfuscation (IO). In C0, a master key of a functional encryption (FE) is hardwired. Given an input z to C0, it outputs a secret key using the key generation algorithm of FE. C0 is as follows:
C0(z)
{ hardwired: msk
out... |
What's the meaning of without loss of generality in the cryptography (Zero Knowledge Proof)?
Without loss of generality, suppose we want to check if a 1 = a 2 . In
the following description, j ∈ { 1, 2 } .
Reference: Zero-knowledge test of vector equivalence granulation of user data with privacy.
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In my scheme, two functional encryptions FE1 and FE2 are used. The function f1 corresponding to FE1 is as follows:
f1_y(x)
{ hardwired msk2
output sk2 = FE2.KeyGen(msk2, (x, y))
}
where msk2 is the master key of FE2.
Then, the user obtains the private key sk1_y=FE1.KeyGen(msk1, y). For any ciphertext c=FE1.Enc(x), ... |
I'm studying some concepts about Oblivious Transfer(OT), and would like to know what is the 1-out-of-2 OT, chosen 1-out-of-2 OT and Random 1-out-of-2 OT, and wonder the relation and difference between these concepts, thank!
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Will Hashing Multiple Times Be More, Less, Or Similarly Secure As Hashing Once?
Flushing out this question:
I saw this claim:
List item: Don't do this: hash = sha512(password + salt); for (i = 0; i < 1000; i++) { hash = sha512(hash); // <-- Do NOT do this! } however if you are going to double hash then do this hash... |
I am new to cryptography, and trying to understand the concepts of LWE (learning with errors) formally. I will state my understanding of the definitions, which might be incorrect.
Definitions According to My Understanding
Let $R$ be a finite unital commutative ring equipped with a probability $\mu$ (whose $\sigma$-alge... |
I am reading about Hardened and Normal child key in chapter 5 of the book "Mastering Bitcoin" by Andreas, along with this detailed thread and BIP-32. Here are some of my understanding about these two procedures:
k: private key // K: public key // i index // c chain code // H HMAC hashing result // Hleft the first 32 b... |
From one-time hash-based signature, one can convert it into 2^d time signature by using Merkle hash tree.
However, it seems to be a trick that enables multi-time signing.
My question is:
is there any use case for a signature scheme that can only be used to sign for a fixed number of time (punch/redeem card)?
|
Recently, I have been reading the original proof of GCM.
It mentioned the properties of "almost universal" and "return zero" for hash function.
I wonder if there is a connection between the two, that is
If a hash function is collision resistant, then it is "unlikely" return zero.
In a more formal way, we have the fol... |
As described in the SSH RFC an initial IV to server, initial IV to client, encryption key client to server, encryption key server to client, integrity key client to server, and an integrity key server to client are generated.
Why does SSH generate a key for server -> client communication and a key for client -> server ... |
Here is quote from gnark documenation.
Note that careful consideration must be given to this step in production environment. groth16.Setup uses some randomness to precompute the Proving and Verifying keys. If the process or machine leaks this randomness, an attacker could break the ZKP protocol.
It sounds like there ... |
Let $g$ be a generator of multiplicative group mod $p$ a prime.
Suppose we know
$$g^{a+km_1}\bmod p$$
$$g^{b-km_2}\bmod p$$
$$g^{a+k'm_3}\bmod p$$
$$g^{b-k'm_4}\bmod p$$
where $m_2m_3-m_4m_1=\phi(p)$ where $\phi$ is Totient and $a,b,k,k'$ are the only unknown and all of $a$ through $m_4$ are of size $\sqrt p$ (we know ... |
I'm doing reverse-engineering a product and identified a critical issue with it. The work is done and the developer was notified, but for my own personal curiosity, I'd like to learn how to exploit it so I can make a small write-up.
The short of it is, the developer is using a fixed key and IV for encrypting multiple s... |
Triple-DES encrypts with the first key, then the second key, then the third key. Two keys are sitting around waiting. Why not encrypt with all three keys at the same time?
You take 192 bits of plaintext (three 64-bit sub blocks) and run the entire 192 bits through an MDS-matrix as a pre-step. Afterwards, in parallel... |
As described in the SSH RFC an initial IV to server, initial IV to client, encryption key client to server, encryption key server to client, integrity key client to server, and an integrity key server to client are generated.
Does TLS use a similar system? If not, Why doesn't TLS use a system like this?
|
I've picked up a grad level computer security class. I read a brief overview on block and stream encryption. I understand and have used PGP in the past and it make since to share your public key. Since the keys for block and stream encryption are extremely import for others not to find them. How do you share them in a ... |
I was considering creating an ML project where it is fed some ciphertext by any classical cipher and would return possible ciphers that encrypted the text. I would have to create a sizeable dataset for it so I was wondering if this idea is relatively feasible before I attempt it.
|
So I am trying to solve some exercises about pseudorandom permutations.
Assume that keyed-permuation $E_k(x)$ is a pseudorandom permutation, where $|x|=|k|=n$. Using $E_k(x)$, we construct an encryption sheme as follows.
$$
c=m\oplus E_k(0^n)\\
m=c\oplus E_k(0^n)
$$
where $k$ is a random key.
The task is to show if ... |
I've noticed that keys for authenticated encryption primitives like AES must be unpredictable and uniformly random in order to be secure. IV values and seeds for PRNGs also have to be unpredictable and random.
My question is: How those unpredictable and random values are different from predictable values that contain w... |
In LWE, we have
$$<a_1,s> + e + \mu_1\in \mathbb{Z}_q$$
for a secret key $s\in \{0,1\}^n$ and $a_1\in \mathbb{Z}_q^n$
This is an encryption of a number $\mu_1$. If we want to encrypt $n$ different $\mu_i$, we need $n$ different $a_i$. With $n$ values $a_{11}, ..., a_{1n}$ we were able to encrypt one single $\mu_1$.
For... |
This is related to this question about solving the following expression:
$$x^{2} + y^{2}$$
This can be factored over the gaussian integers as
$$(x + iy)(x - iy)$$
If one could factor a sum of two squares and take the integer component $x$ one could solve the problem.
Can Shor's algorithm factor a term over gaussian int... |
In Linear Approximations of Additions Modulo $2^n$, Wallén shows how to compute the correlation of the modular addition of two binary bit vectors. A simple recursive procedure was given by Schulte-Geers in On CCZ-equivalence of Addition mod $2^n$. However, these papers both assume that the summands are uniformly distri... |
I am reading the original paper of Argon2 authors and I can understand the algorithm except the indexing part. Can anyone explain two things:
the indexing process and the mapping $J_{1}$, $J_{2}$ to reference block index.
How the $B_{i'j'}$ are fixed in Argon2d, Argon2i and Argon2id.
I tried to simplify things by tak... |
Im just starting out learning some cryptoanalysis techniques. I came across an idea which analyzes the vigenere cipher. Essentially the video explains that there is a standard english probability density function for each letter of the alphabet. And the letters used in the encryption of the message is called the key. A... |
I have a question about $z$ in Classic Mceliece Algorithm specification.
I have no idea about this $z$!
In parameter set kem/mceliece348864, Field polynomial $f(z) = z^{12} + z^3 + 1$.
is this $z$ in field polynomial same as the $z$ in pic?
If this is right, the value of $z$ in the pic for kem/mceliece348864 is $(z^1,... |
Let's assume such a scenario.
Person A will broadcast his public key and
person B will broadcast his public key. They can now communicate.
But let's say that suddenly another person C will write to person A impersonation person B.
How can a person B prove their identity.
We can implement a signature system. Person A ... |
Proposition Let π be a protocol that securely computes a functionality f in the presence of malicious adversaries. Then π securely computes f in the presence of augmented semi-honest adversaries.
Proof. Let π be a protocol that securely computes f in the presence of malicious adversaries. Let A be an augmented semi... |
Shor's algorithm can (efficiently) solve equations of the form:
$$n = pq$$
and
$$n = x^{2} + y^{2}$$
This question is simple: Can Shor's algorithm solve these equations in polynomial time when they are performed with finite arithmetic instead of over integers? i.e.
$$n = pq \bmod k$$
and
$$n = x^{2} + y^{2} \bmod k$$
S... |
A cyclic sequence can be produced with
$$s_{i+1} = s_i^a \mod N$$
with $N = P \cdot Q$ and $P = 2\cdot p+1$ and $Q = 2\cdot q\cdot r+1$ and $r = 2\cdot u \cdot v \cdot w +1$ with $P,Q,p,q,r,u,v,w$ different primes
We can now project a random number $x_R$ into a subspace of size $2(r-1)+4$ with
$$s_R = x_R^{\beta} \mod ... |
In ECDSA, $f(G)=r$, where $r$ is the $$-coordinate of group element $G$. Now it is known that $f(G)$ is not uniform(Why isn't $f(G)$ uniform in ECDSA?). Then in which range $f(G)$ is uniform?
Let $\langle G\rangle$ be a cyclic group on the ECDSA elliptic curve with the generator $G$, and $S=\{x|f(W)=x,\forall W\in\lang... |
The process of Shamir secret sharing degree reduction in multiplication gate is explained in
the following link
Now, based on the secret sharing that done by a degree one polynomial, we must be able to reconstruct the secret, i.e. $10$, with each of the $2$ shares out of the $3$ shares $(3, 7, 0)$. Nevertheless, the re... |
Some implementations of a Schnorr signature will determine the challenge as follows:
$c=H(kG \mathbin\| X \mathbin\| m)==H(rG+cX \mathbin\| X \mathbin\| m)$, where:
$c$ is the challenge
$m$ is the message being signed
$X$ is the public key of the signer such that $X=xG$
$G$ is a well-known base point
$x$ is the private... |
With the proliferation of https, and one of the primary functions of my pc being browsing the intarwebs, it occurs to me that my cpu is spending a lot of cycles doing AES en and de cryption. For the "average" PC (i.e. not servers or supercomputers, which is an interesting but different question), about what percent of... |
I am trying to understand SHA2 - 512 algorithm, so I am following this document which has the intermediate values for the string "abc". At t=0, the values for f, h and g are straightforward. But I am not getting the same value for e, which suggests that I am doing something wrong when I am computing $T_1 = h + \Sigma_1... |
I cannot seem to understand why the function $F$ defined in Theorem 7.1 of the paper “Permutation rotation-symmetric Sboxes, liftings and affine equivalence” is described as “a bijection on $\mathbb{F}_2^n$”.
The input contains $n$ bits, yet the given definition seems to imply that the output contains $k=n-2$ bits: $$F... |
I need to generate a deterministic identifier from some user data. One of the user data items is highly sensitive, but the other two are not. The identifier will be sent to an external party regularly, so it must not change in the future - i.e. the same input should always produce the same output in the future.
A pseud... |
If I have public element $W=K^r$, and $K=v^x$ should be kept secret where $v$ is a generator in $\mathbb G$, is there a way to produce a zero knowledge proof on x and r such that $W=v^{x \cdot r}$ while committing to $x$ and $r$ individually.
Thanks.
|
Consider the following version of Learning With Errors.
You are either given $(A, As_1 + e_1, As_2 + e_2, \ldots, As_k + e_k)$ or $(A, u_1, u_2, \ldots, u_k)$, where
$A$ is an $m \times n$ matrix whose entries come from the field $\mathbb{Z}_q$ --- the entries are sampled uniformly at random.
$u_1, u_2, \ldots, u_k$ a... |
The following link documents a proposal for a TLS-like alternative for constrained devices.
https://github.com/lake-wg/edhoc/blob/4f56898808989e449cc412a8b136674202a0ddce/draft-ietf-lake-edhoc.md#implementation-considerations-impl-cons
Unlike TLS1.3, the proposal does not make use of running hashes. Citing the proposal... |
I am trying to verify a zk-SNARK from a solidity contract offline, in Rust.
This is the verifying contract that checks the proof in the solidity side.
And this is the transaction that carries the proof and the public inputs.
The proof is valid and I have been able to replicate the validation offline using Solidity.
How... |
In an attempt to understand modern ransomware mechanisms I landed on a blog post about LockBit.
This one is confusing to me since:
This ransomware generates a pair of RSA keys on the infected
device which is used to encrypt the AES keys used to encrypt files.
Then, the private key of that RSA key is encrypted with a ... |
Some proof of work hashes have a lot of initial zeros. Do the arguments to the hash functions giving these zero containing hashes have anything in common, or are they stochastic?
What I am looking for is if there are any ways to choose the hash function argument distributions in order to improve the rate of initial ze... |
P=11
Q=29
Euler=280
e=3
d=187
When i take a message “88” for example;
Encrypt: 88^3(mod 319) = 88
Decrypt: 88^187(mod 319) = 88
Why does the encrypted message equals the decrypted message and why does the plaintext message equals the encrypted message?
|
Suppose $n$ parties where $t$ are honest want to perform a distributed key generation protocol. There are many existing schemes. In the simpler setting where all $n$ parties must be online, otherwise the protocol aborts, does the following simplified scheme suffice?
Each party $i$ samples $x_i \gets \mathbb{Z}_p$
Comp... |
Was that just a coincidence, or did the 2 "shattered" pdf files whose SHA-1 hashes are identical had to be small in size (412KB) to make the collision attack easier?
|
David Wong in his book Real-World Cryptography writes:
In 2013, following revelations from Edward Snowden, it was discovered that NSA
had purposefully and successfully pushed for the inclusion of backdoor algorithms in
standards (see “Dual EC: A Standardized Back Door” by Bernstein et al.), which
included a hidden swi... |
Suppose we only have to use factoring as trapdoor function and we are disallowed to use other trapdoors, are there applications currently deployed which cannot be done?
|
Problem Statement
Imagine you have a set (no duplicate elements) e.g. S1 = {'a', 'b', 'c'}.
You wish to share a private (and ideally both small in size and integrity protected) representation of this set with another party (who could have pre-shared keys with you) where they can verify (yes or no) if some element of th... |
I am trying to learn about RSA digital signatures, and have a question about the verification process.
My understanding of the set-up is the following:
The signer chooses two secret primes $p$ and $q$, and a verification exponent $e$ satisfying $\gcd(e,(p-1)(q-1))=1$, then publishes $N=pq$ and $e$.
The signer computes ... |
Something that's puzzling me for a while is how we could calculate approximately the energy cost of using AES, for a company like Amazon or Google. How likely it is due to the nature of their business model that its an important part of their fixed cost? Considering key generation, encryption and decryption etc of so m... |
I have a question about database security. This is a scenario I have.
The data is encrypted using symmetric (i.e., AES) and stored in a database, while the secret key is stored on the client side, so when I need to request any of this data, I send a SQL query with the secret key to get this data and then forget the key... |
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