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According to a Lecture from Lecture notes of a Professor of Purdue University "Diffusion means that a change in any plaintext bit must propagate out to as many ciphertext bits as possible." I can't clearly understand how S-box introduces this diffusion in DES. Can anyone explain with an example? Is it because a change ... |
The prover has $n$ group elements $g_1, ..., g_n$ and wishes to demonstrate the knowledge of the discrete logarithm to base $g$ for each of them, i.e, for each $i \in [1,n]$ she knows some $e_i$ s.t. $g_i = g^{e_i}$. We know that by applying Fiat-Shamir to the Schnorr's protocol, we can get $n$ non-interactive proofs i... |
Andreas Antonopoulos effectively states: an input of 256bits of entropy into PBKDF2-HMAC-SHA512 will ONLY output a 64 byte hash containing ~128 bits of entropy. He states the algorithm essentially ignores the extra entropy going in, and it is "wasted" entropy.
IS THIS TRUE? Can anyone explain why?
Source: (starts at 14... |
Given y = g ^ x is discrete log hard on some finite field, is y = g ^ (kx) also equally secure if the value k is a publicly known value which was randomly selected from a uniform distribution ?
To my understanding, if k and x are independent and chosen randomly, then the security of the discrete logarithm problem is no... |
In a cryptocurrency with privacy e.g., zcash, where does proof generation take place? Can it happen in the client's device every time a transaction is performed?
If it happens in client's device, are there possibilities of malware compromising the privacy?
|
What would be recommended way to make deterministic password based file encryption?
I can use SIV mode, but KDF (like Argon) takes salt for which I could use SIV tag, but I cannot make it because I need key first.
I could use hash of file contents as salt, but that would make it 3-pass. If I would use some other single... |
In Rabin-Miller primality test, let N be the number you're checking for primality. Here N = 78007.
Let m be the number you get after dividing (N - 1) by 2 several times until you can no longer do so. In this case, m = 39003.
The next step is to pick an A, here we pick A = 3.
Now we calculate b0 = Am mod N.
Now, if that... |
I'm reading through a paper called Unconditionally Secure Signatures (https://eprint.iacr.org/2016/739) and to generate keys, the authors select $\epsilon-ASU_2$ functions, such that:
For any $m \in M, t \in T, \vert \lbrace f \in F : f(m)=t \rbrace \vert = \vert F \vert / \vert T \vert$
For any $m_1, m_2 \in M, t_1, ... |
In the realm of secure Multi-Party Computation (MPC) schemes, there exist two fundamental concepts known as the covert adversary model and security with abort. From what I understand, both of these concepts involve situations where if a corrupted party engages in dishonest behavior, the honest parties have a reasonable... |
In these two papers the authors mention the "quality" of a trapdoor
[GPV] https://eprint.iacr.org/2007/432
[MP] https://eprint.iacr.org/2011/501
But the best detail on this matter I could find was "The quality of a trapdoor S roughly
corresponds to the Euclidean lengths of its vectors — shorter is better."
I wonder w... |
I'm following the discussion in the question about RSA and what if we set $p<q$.
So, what if we mistakenly let $p<q$ and proceed with the private keys creations; that is, we pick up $p, q, e$ and derive from them: $dP,dQ, qInv$ (I'm using the CRT key structure in PKCS#1).
So, by trying to create those private-key eleme... |
In https://crypto.stackexchange.com/a/27828/79037, it's indicated that one can "save space" by using something globally-unique, like an application-wide "pepper", together with something locally-unique (e.g, a user-id field, unique per-user). In other words, by simply "deriving" a salt (from some other fields/values/et... |
Problem
Suppose there is an entity with some users. The users are split into subsets (determined by the entity) and the entity needs to create public commitments to these subsets such that only a user can determine which set they are in. The sets need to be some minimum size, $m$.
More formally
Let $U$ be a set of user... |
In Regev's publication "The Learning with Errors Problem", a naive algorithm is given on page 3 that can be used to tackle the LWE problem. This is the statement:
Another, even more naive algorithm is the following: keep asking for LWE samples until seeing $poly(n)$ equations of the form $s_1 \approx . . . $ (i.e., a p... |
Is there any study that has looked into what is the minimum number of ciphertext characters one needs to have to do a reliable frequency analysis?
It would be nice to know the evolution of the accuracy of the analysis as the number of characters considered increases, but I haven't found any well done study.
|
I'm reading Rivest et al.'s "How to leak a secret", but I'm having a hard time understanding step 4 of the generation procedure. This could be because of my own lack of knowledge regarding operations on ring but the following:
makes very little sense to me. How am I supposed to solve this equation? I've tried looking ... |
I am right now studying Pseudo Random Functions. I have a couple of constructions made of a safe PRF F:{0,1}^l x {0,1}^l -> {0,1}^l.
I am unsure of wether these are safe ( in terms pseudorandomness ) or not. I will try and reason. Correct me if I am wrong.
1.) F1 = F(k,x)||k
F1 is not safe, since the concatenation of k... |
Passkey is nice. The math is nice. The tech is nice. https://security.googleblog.com/2023/05/so-long-passwords-thanks-for-all-phish.html
What I still dont see after sooo many hours: what software creates the passkey. User autonomy is important and it is a (private) key question (pun intended). I do not really see this ... |
Do $\exists $ keys $k_1, k_2$ which given any (128-bit) message $m$ are related to each other by being
commutative to each other with $AES(AES(m,k_1),k_2)=AES(AES(m,k_2),k_1)$ $\forall m$ and generally $AES(m,k_1) \not= AES(m,k_2)$
or $k_2$ is equal to applying $n$-times $k_1$ with $AES^n(m,k_1)=AES(m,k_2)$ with $AES^... |
My understanding is that an elliptic curve $E$ over a finite field $\mathbf{F}_q$ has a bit security of $\sqrt{q}$ assuming Pollard rho or Baby-step giant-step. In this thread, it is explained that the field $\mathbf{F}_{2^{256}}$ has a bit security of $128$, but the field $\mathbf{F}_{2^{256^{2}}}$ supposedly only has... |
It seems like every CCA-secure KEM1 has some sort of check that the decapsulator performs. Sometimes failure will result in rejection ("explicit rejection") or the decapsulator will simply return a random value ("implicit rejection", like in Fujisaki-Okamoto without aborts). But in any case, the decapsulator knows when... |
The Python secrets module claims to produce cryptographically secure random numbers. I did some research on which random number generator is used when you call the secrets module on Windows. I found the following:
->secrets uses random
->random uses os.urandom
->os.urandom uses _PyOS_URandom() from Python/bootstrap_has... |
In a course I'm taking the following question came up:
A 51% attack means:
A. 51% of the nodes are bots
B. 51% of the nodes are hackers
C. 51% of the nodes are offline or disabled
D. 51% of the nodes agree on something
I had answered D, but the correct answer was given as B.
As far as I am aware, I be... |
If both communicating sides end up with the same secret 3000-bit key, is it enough to XOR each byte of the messages with each byte of the secret key to make it secure?
Wikipedia says it is, but I wanted to ask if this is still the case nowadays.
That would mean each message can be up to 375 bytes in size, so that each ... |
There is this cool paper https://eprint.iacr.org/2017/395.pdf exposing a side channel protected implementation of keccak, in particular Domain Oriented Masking for the Chi function.
The Chi function is a 5bit S-Box, so can also be seen as a lookup table of 32 5bit values.
My question is, in an hardware implementation w... |
If we talk about the security of public key encryption in Regev's lwe system, if attacker would have knowledge of $(u,u'):[\mathbf u=A\mathbf r, \mathbf u'=\mathbf b^t\mathbf r + \mu q/2, \mathbf r\in\{0,1\}^m]$ and $\mathbf b$, then value of $\mathbf r$ in $\mathbf u'$ can be guessed easily by the knowledge of $\mathb... |
Is there any (k,n)-threshold encryption scheme, such that the decryption process is non-interactive, i.e., the decryption can be processed "in a line" where each party "in the middle of the line" receives a partially decrypted ciphertext, perform partially decryption itself, and then pass it on to some other party?
It ... |
I am trying to implement the Schnorr’s identification protocol in C. I need a safe prime in order to be able to find a generator of the cyclic group efficiently. The problem is that my program takes too much time to find the safe prime. I am using Libsodium for generating random numbers and GMP for arbitrary precision ... |
I wrote a command line application for encrypting/decrypting files to your local machine. The idea is you have an asymmetric key pair where the private key is stored encrypted and the public key is stored in plain text. This way you can encrypt data without having to "unlock" the application (decrypt your private key),... |
I am trying to run the github code in windows 11. I don't know what all I need to install in my laptop to run the C++ code. It would be a great help if someone can point out the steps to run the code.
|
We all know that block Korkine-Zolotarev (BKZ) algorithm is essentially a deterministic lattice reduction algorithm. However, in the actual implementation, the BKZ algorithm contains some randomization, For example, the actual algorithm will do some random unimodular transformations on the lattice basis in order to ob... |
Assume I have a PRF $F$, with polynomial key length $s_{F}(n)\geq n$, and output length $l(n)$.
I need to construct a PRF $F'$, with key length $s_{F'}(n)=n$ and output length $l(n)$.
I thought about the following construction:
$$F'(k,x)=F_{F(k',0)F(k',1)...F(k',m)}(x)$$
where $|k'| \leq |k|$ is an output of $s$ for s... |
Hey there guys and gals,
so I am right now studying topics regarding pseudorandomness.
I was wondering why, for example with CBC-MAC oder a regular CBC blockcipher, we use padding instead of a PRG. If the block size is not a whole multiple of the clear text m, we could just use a PRG with the seed as the last block of... |
any paper mentioning the performance decreases with N?
why when N is increasing, the performance decreases? any papers?
BR
|
Say we have an element $g=H(m)$ in a group (this element may or may not be a generator of the group).
Are there signature schemes that enable to sign this element, and then to be able to derive a signature of $g^a$ for a chosen $a$ without the presence of the signer?
Thank you for your help.
|
I'm trying to design a zero-knowledge protocol for the creation of a shuffled deck of cards for use by two players. Naturally this requires that neither player knows the order of the cards after the shuffle, nor what card was drawn by the other during play, but I'd also like to be able to do this without needing a trus... |
From what I have understood of naive RSA (without padding) so far, it seems that A and B must first decide on the prime factors in order for B to generate its private key to decrypt A's message.
I do understand that the RSA system helps in the establishment of a secure "channel", rather than having to rely on creating ... |
My Main Question:
Do we always require to be sure that the inputs of the parties in a secure multi-party computation are independent? i.e., one party's inputs do not have dependency on the other parties inputs? (this paper claims that the inputs must be independent)
Explanation and subquestions:
If this is the case, i... |
Suppose I have a 2048 bit prime number p. Now for the group $Z_p$, could someone please tell me an efficient algorithm to check whether a randomly chosen number is a generator for the group or not
|
I have a file with an EC Public Private Key Pair and curve parameters:
openssl ec -in keyfile.pem -noout -text
read EC key
Private-Key: (256 bit)
priv:
aa:bb:cc:aa:bb:ccaa:bb:ccaa:bb:ccaa:bb:cc:aa:
aa:bb:cc:aa:bb:ccaa:bb:ccaa:bb:ccaa:bb:cc:aa:
pub:
aa:bb:cc:aa:bb:ccaa:bb:ccaa:bb:ccaa:bb:cc:aa:
aa:bb:cc:... |
In LWE, the error term $e$ is "classically" obtained from the discrete normal distribution. Why is it so often found that this distribution is used? Are there other possibilities for distributions?
The secret $s$ is often uniformly distributed, this makes sense, if one wants to "hide" just the secret in the (uniformly ... |
I'm working on a project that involves broadcast (uni-directional) streaming and requires non-repudiation. Essentially, a device broadcasts a data stream over the air, and any receiving station needs to be confident that the data was actually transmitted by the claimed device.
My initial thought is that the broadcaster... |
What are some approaches to find (ideally many/all) pairs of numbers $(x, y)$ with $ x \in [x_{\text{low}}, x_{\text{high}}]$ and $ y \in [y_{\text{low}}, y_{\text{high}}]$ such that the following holds:
$$a \cdot x \equiv y \pmod{m}$$
Exhaustive search is not feasible since the intervals are each greater than $10^{3... |
I referred to the explanation of encryption mode from Wikipedia, but I'm confused now, and I went to find some books about Cryptography, but it didn't solve my confusion.
The CTR mode uses Counter to participate in encryption.
But in Wikipedia, the encryption process is as follows:
It can be seen that both Nonce and C... |
I want to generate some tokens for client as http cookie
can I md5 them with salt and then use "<random token>"+"<md5>" as the token for they
can be verified in a cheap way
is it safe?
|
Kerberos (and I assume other Trusted Third Party protocols) use (hash) an existing shared secret key to create a session key used for authentication. I read that this authentication secret key can then be used to create another secret key to be used as the session key for message encryption.
"If a message integrity or... |
Are there any cryptographic proof systems that rewind the prover to argue soundness but are not proofs of knowledge? In particular, I would be very curious to see examples of proof systems where rewinding is useful for arguing soundness but does not seem to suffice for witness extraction.
To give some nonexamples, Schn... |
I'm considering some non-cryptographic PRNG which uses multiplication of two 64-bit or 128-bit random numbers at some point.
__uint128_t a;
__uint128_t b;
__uint128_t result;
result = a * b;
Is this constant time? I don't think so, especially since it takes less time to multiply two small numbers than when they are ... |
I am currently analyzing the communication protocol of HomeKey. Here are two traces between the lock (reader) and the device (card).
First set:
r2c > 80 80 01 01 6B 5C 02 02 00 87 41 04 34 BC DE 44 04 90 01 8D 24 02 18 2B 80 46 2A D6 25 7D 52 03 64 10 5D 9C 66 5D 20 9A 51 BC 18 DF 23 4A A2 C2 2B 01 2F EC FF 3C 96 D7 82... |
I learned the Public Key Recovery algorithm for ECDSA, and wonder if we can use it in DSA. The answer seems to be no, but details are welcome.
|
I saw theorems stating that RSA-OAEP (or the similar variant OAEP+) is CCA-secure in the random oracle model.
I wonder about the following:
Is RSA-OAEP (or even OAEP+) CPA-secure in the plain model? If so, what properties does the hash functions need to hold?
Are there any lower bounds for the padding length compared ... |
We are given some distinct DSA signatures $(r_i,s_i)$ and the distinct hashes $H_i$ of the corresponding messages. The signatures and messages are non-maliciously made per the same known group parameters $(p,q,g)$ (say the 2048-bit MODP group with 256-bit prime order subgroup of RFC 5114), using either one of two disti... |
Could you clarify where the stack object is typically generated? Is it created on the sender's device or the recipient's device?
If I send funds to a multipay stack that was created on another device currently offline, what would happen? Would the payments defined by the stack be delayed until the offline device is b... |
In use-case we have a (random) generator $g_1$ and perform operations $g_1^{a}$ for known $a$ inside a safe elliptic curve modulo $p$.
Is there any function $f$ which gives us a new (most likely different) generator $g_2$ out of $g_1$ and $a$:
$$f(g_1,a) = g_2$$
and the inverse given a generator $g_2$ (which can also b... |
I'm trying to interpolate a Shamir secret in the exponent based on Boneh's and Shoup's book, Section 22.1 and Corollary 22.2. I think I understand how the scheme works, but I'm stuck now with some computations in a toy example that I've come up with. I'm a beginner so likely this is a beginner's mistake, any help would... |
I took a look at the Kyber and Frodo procedures and found that the ciphertext consists of two components. In Kyber these are the lines 5-7 in algorithm 2 $c := (\mathbf{u},v)$ and in Frodo line 8 of algorithm 10 $c \leftarrow (C_1,C_2)$.
One part of the ciphertext pair contains the message to be encrypted, that is $v$ ... |
I know that compressing data before encrypting it can cause a compression oracle attack such as in the CRIME and BREACH attacks, but if only part of the data is compressed, e.g. non-user controlled and/or non-sensitive data, and the user controlled/sensitive data is not compressed, but they are then encrypted together,... |
According to the ZKP MOOC lecture by Dan Boneh, it is possible to batch proofs from different polynomials and different points into a single group element:
Nonetheless, I haven't been able to find any protocol that provides this functionality since most of them batch proofs of the same polynomial on different points.
... |
I'm trying to implement HMAC SHA256 (I've implemented SHA256 successfully).
I am trying to find examples where they show the results after each HMAC stage (XOR, append, H etc).
Does anyone know of any resources which contain examples with the results from each step?
|
Do any parallelizable cryptographic hash algorithms that allow for quick—preferably constant-time—recalculation of a hash result upon updating a portion of the data input exist?
I know that BLAKE3 is called "parallelizable", but a Merkle tree doesn't seem like it's what I'm looking for when the time taken to recalculat... |
I am a student in the process of creating a firewall circumvention program based on smuggling data inside of legitimate HTTP. I have limited cryptographic knowledge.
I need a way to encrypt my higher-level protocol such that I get a random bytestream indistinguishable from random data that can then be disguised as imag... |
1) For authenticated disk encryption, there are extra data such as IV or tag that need to be stored for all the alternative mods that are placed in Table 1. For these data, it will be necessary to use a sector other than the sector where the encrypted data is located. Consumed space by extra storage of tags or iv is re... |
I am trying to understand how OpenSSL adds points on an elliptic curve. I have understood from here that ossl_ec_GFp_simple_add() is where the addition op works. Can anyone explain the algorithm used here? I know that it's working on Projective/Jacobian coordinates. Is it following the algorithm explained here?
|
I want a family of efficiently computable random-ish bijections $f_{k,n} : [0..n) \to [0..n)$ for $n \le 2048$. We cannot make the $f_{k,n}$ be secure for encryption at this domain size of course, but I really only need the set $f_{k,n}\big( [0..n/3) \big)$ to be distributed somewhat randomly. In particular, those se... |
This is most likely a dumb question. I'm doing a mathematical research project that overflowed a bit into cryptography. It got me thinking about something. Can the following cryptosystem work?
Let Alice and Bob share a private key $d$ using the Diffie Hellman key exchange, where $d\in \mathbb{F}_p$ for some prime $p$. ... |
I am reading the paper Pseudorandom Quantum States,where the following candidate was shown to be a Pseudorandom state, called the complex random phase state:
$\mathrm{PRF}_k:X → X$ be a keyed pseudorandom function where $X = \{0, 1, 2, . . . , N − 1\}$ and $N = 2^n$ with $n$ being the security parameter. The family of ... |
Let's temporarily work upon the assumption that proper KBKDF functions do not exist, for the sake of argument.
Would keccak256 be a secure choice for a KBKDF that derives 256-bit keys from a 256-bit master secret $k_{256}$ with an arbitrary-length derivation path $p$? And is this true in general for hash functions that... |
I have several mathematical operations on binary numbers that are special cases of more general arithmetic operations. I am wondering whether there exist more specialized algorithms purpose-made for these edge cases that are faster than the general algorithm. Could someone point me to such algorithms if they exist?
Ple... |
This protocol is designed to establish a session key K'AB between two parties without the interaction with a server. In this case, the key KAB is a long-term key shared between Alice and Bob. I am supposed to create an attack, where i imitate Bob. I think it is a problem with the missing verification of Bob. I'm stuck... |
The LWE assumption states that it is hard to distinguish LWE samples from uniformly distributed samples. That is, the distinction $(A,b)$ with $A$ and $b$ uniformly distributed, is hard to distinguish from $(A,b=As+e)$, where $A$, $s$ are uniformly distributed and $e$ follows a different distribution.
However, in crypt... |
$\bullet$ What does private-key functional encryption mean? Or functional encryption in private-key setting?
Wasn't functional encryption a generalization of public key encryption? So now, why do we have private-key functional encryption?! It's a little confusing.
I've seen a few sentences in Romain Gay's PhD thesis [R... |
I have read about Montgomery Multiplication on several sites, but I haven't found any examples on specific numbers that explain the algorithm to someone who doesn't have a PhD in number theory.
I know it involves converting the numbers into a special form called Montgomery Form, which makes modular operations easy and ... |
I was wondering if anyone could clarify the differences between PCD vs Recursive SNARKs(like pickles) vs Non-uniform IVC(like hypernova)
They all seem very similar to me
|
I've developed an algorithm for fast modular exponentiation modulo composite numbers with known factorization. I'm not very well versed in cryptography, so I'm wondering if any of you know of an application of this algorithm to some cryptosystem. Even if there is no cryptosystem where this can be used, I'm also interes... |
Let $r(b,t)$ denote the bitstring $b$ rotated to the left by $t$ bits: for example, $$r(00110101,5)=10100110.$$
Let $m(b_1,b_2,b_3)$ denote the majority function: for example, $$m(10010111,00101110,10100000)=10100110.$$
Consider the following game. Player A picks three arbitrary $n$-bit strings $(S_1,S_2,S_3)$ and nine... |
I have come across the TenSEAL tutorial on implementing homomorphic encryption (HE) and they mention the global_scale parameter.
(https://github.com/OpenMined/TenSEAL/blob/main/tutorials/Tutorial%202%20-%20Working%20with%20Approximate%20Numbers.ipynb)
global_scale: the scaling factor, here set to 2^40.
I am struggling ... |
It seems to have something to do with their bootstrapping technique, that is build on blind rotations, but I fail to see why less than $8$ bits are used.
|
From the PLONK paper.
Page 18
We describe an optimization by Mary Maller to reduce the number of $F$-elements in the proof from $M$. We begin with an illustrating example. Suppose $V$ wishes to check the identity $h1(X) \cdot h2(X) − h3(X) \equiv 0$. The compilation described above would have $P$ send the values of $h... |
0
I have two questions:
Can someone point me to some solution providing multi-party {t,n}-threshold ECDSA?
I imagine that such a scheme works first by creating an ECDSA private key then sharding it to n subkeys, t of which subkeys are required to generate the initial ECDSA private key. Am I right?
I would appreciate ... |
The Pedersen hash is a low constraints friendly hash for Zk-Snarks.
Unlike many algorithms, the Pedersen hash returns a point P = (x,y) on a curve as a hash. Depending on the selected curve, there can exist a fast deterministic way to compute a different input that yields −P=(x,−y) using the Weierstrass form or −P=(−x,... |
I've been experimenting in python with different approaches to cryptographically secure pseudo random number generators, comparing them using the NIST testsuite implemented by https://github.com/InsaneMonster/NistRng/tree/master. My requirements are:
must be cryptographically secure, so its output is suitable as encry... |
For the Substitution Cipher, for functions such as $$f(x) = x^k \pmod{26}$$ or $$f(x) = x^k + k \pmod{26}$$ (functions that consist of x^k), why do the values of k=5 or k=7 or k > 10 have one-to-one mapping? I know 5 and 7 are relatively prime to 26, however, what about 3 or 9? Also why do it map when k > 10?
|
After reading that about "37% of the 256-bit outputs" of SHA-256 are unreachable when fed only 256-bit inputs [1] I'm curious & confused. The formula from the proof here considers a fixed "h-bit" input & output. How does this translate to the maximum number of internal states that are reachable within SHA3?
Does this m... |
I'm working on a system where I need to sign some data using an ECC private key and share the data and signature over a BLE ADV packet. Since an ADV packet is limited in space, I can't use a full ECDSA signature as the output is too large. As far as I understand, you can't readily truncate an ECDSA signature as you can... |
Good morning,
I've been struggling with this protocol for the last few days and I'm out of ideas now. The goal is to impersonate Bob by just modifying or dropping packages. The attacker(me) is a Proxy that is between the clients and the servers so any messages are first sent to me and I send relay them to the servers.
... |
print(tan(int.from_bytes(open("plain.txt", "rb").read().strip(), "big")).n(1024))
Its sage code. How difficult or easy is it to recover the plaintext from the output of this code? I don't think the hash collision, or second preimage attack will be usefully unless we know the length of the plaintext.
Is there any poss... |
We (collectively) salt passwords, then hash them; maybe even run them through something like PBKDF2 first (depending on how the password will be used).
The end result is that we have a string $p$ and map it to a fixed-length string $p'$ using a surjective transformation with the property that it is difficult to find an... |
Let's suppose I have two 2GiB files and I want to encrypt them using One-time pad (Vernam cipher), but I don't want to store two big keys.
May I use only one key for the two files if I encrypt the One-time pad key two times with a block cipher with two different keys for block cipher? I mean, take the One-time pad key,... |
I have a congruential generator where
$$
r_{n+1} = r_n^2 - c\;(mod\;p)
$$
known $r_0$, $c$ and $p$ can i get $r_n$ without having to compute all the previous values?
|
so recently I've been exploring zk-SNARKs algorithm, and I have a maybe stupid question. For example, let's take $x^2+x+1$ and make an algebraic circuit from it:
$y=x*x$
$sum=x+1$
$out=sum+y$
(First question: are finite fields needed here?)
Now we need to construct a R1CS to each gate. Our variables and one: ${1, x, ... |
I am currently trying to solve a training challenge based on AES with CBC.
This is the infos I'm given:
KEY = "yn9RB3Lr43xJK2██".encode()
IV = "████████████████".encode()
msg = "AES with CBC is very unbreakable".encode()
Those spaces are unknown characters, and I also have the output:
c5██████████████████████████d49e... |
In round 4, protocol evaluates a(zeta), b(zeta), c(zeta), Sσ1(zeta), Sσ2(zeta). I know linearisation trick in round 5 implies the identity of other terms. Can we evaluate other term e.g. Sσ1(zeta), Sσ3(zeta) instead? Is there any consideration behind these selected terms in paper?
ref:
PLONK paper: https://eprint.iacr... |
Consider two data streams $a_1,\cdots, a_n \in [a_{min}, a_{max}]$ and $b_1,\cdots, b_n \in [b_{min}, b_{max}]$, Such that $[a_{min}, a_{max}]$ and $[b_{min}, b_{max}]$ do not overlap.
A Differential private mechanism (Laplacian with privacy budget $\epsilon$) with zero mean and scale parameter $\beta$ is applied to th... |
I've been reading "Misuse Attacks on Post-Quantum Cryptosystems" (https://eprint.iacr.org/2019/525). In what scenarios are the attacks described in the paper applicable? Is it specifically if a key is reused to generate more than one encapsulated key? Or is it more general? Does it apply to all 'unfailing' reconciliati... |
Rust and NodeJS implementations of ECDH on secp256k1 produce different shared secrets, when using identical keypairs:
NodeJS:
sk1 <Buffer 71 17 9b 99 1d 76 93 de 81 3a ea a5 bf a2 41 a2 ac 9e 05 35 86 7e bf 8f 6b 1b 08 84 47 2e f4 a7>
pk1 02de4cba976ab77795c46c1c3b95afc077b17afe1bca02d28963a3bcdd9c082168
sk2 <Buffer 1e... |
Assume the following:
$E: \{0, 1\}^k \times \{0, 1\}^b \rightarrow \{0, 1\}^b$ is a block cipher with a $k$-bit key size and a $b$-bit block size.
$T$ is a $b$-bit authentication tag that is guaranteed to be untampered with (e.g., by being calculated abd stored by a trusted system).
$X_i$ represents the $i$th of a str... |
Let's say we embed a text using steganography by modifying an existing cover object.
What would be the steps needed to be done on the message?
I can think of
source coding (compression)
channel coding (adding redundancy)
encryption
Do I forget anything? What methods would you use for each step? And how the efficiency... |
I would like to understand how Keccak's permutation function is reversible. The difficulty I have is with the $\chi$ step that uses the and operator which is not revertible. All the other suboperations are using xor and rotations which can be reversed.
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Recently, I read here on Crypto SE that $2^{60}$ doesn't provide enough resistance to current adversaries. Could someone please provide me with good references related to that threshold, or any updated versions of it, say, $2^{70}$ or $2^{80}$?
I made an effort to find the exact discussion, but, unfortunately, I was un... |
Suppose that a prover holds two secret values $x,y\in\mathbb{F}$ and both the prover and verifier have $z\in\mathbb{F}$. The prover wishes to prove that $z=x+y$ without revealing $x,y$ to the verifier.
We can further assume that the verifier has access to some oracle which confirms whether commitments $X,Y$ to $x,y$ ar... |
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