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I'm currently working on implementing digital signatures on the curve secp256k1 (for learning purposes only), and I'm having some trouble implementing ECDSA on curve secp256k1. As I understand it, this curve is a koblitz curve, which means it can't be written in the Montgomery form. Due to this limitation, I'm unable t... |
We have a classic web application, and when a user sign in, we return a session token (UUIDv4). The user can choose if the session should expire when the browser/app is closed or if he prefer to always be connected (1 year at least).
If an attacker get the session token, I want a way to mitigate the possibility to uses... |
Assume a message protocol whereby one time pad messages are authenticated with a Carter Wegman type hash on the ciphertext, or some similar construct utilizing a unique authentication key per message.
Since this is a OTP system, there is a store of key material at both the sender's and receiver's ends. Some material is... |
FALCON is a cryptographic algorithm for digital signature, but is it slower than actuals algorithms (ECDSA)?
|
In the MixColumns step of AES, one multiplies each of the columns of the $4\times 4$ box of bytes by the polynomial $a(x)=\{03\}x^3+\{01\}x^2+\{01\}x+\{02\}$ (modulo $x^4+1$). But in this polynomial, the coefficient $\{01\}=1$ is repeated twice. Why is it acceptable for the MixColumns step of AES to have a repeated coe... |
I'm experimenting with the parameters for argon2, using argon2_cffi.
Whereas the iteration count or time_cost, and the memory_cost have obvious bearings on the speed and security of the result. I've not seen any guidance on a maximum for the parallelism parameter, other than enough for all the threads you have.
I have ... |
Here, an user says about using a seed to generate a key that is larger than the digest size:
"Do not use hash chaining: that's a bad way of constructing a key derivation function from a hash. If the output is H(S) || H(S||H(S)) || H(S||H(S||H(S))) || …, then it's possible to reconstruct the whole output from the first ... |
It's difficult to implement AES securely and efficiently if the adversary can observe the timing and (approximate) location of memory accesses, unless you have dedicated hardware. The naive implementation uses lookup tables, which are vulnerable to attacks based on caches or on memory bus contention. Timing-invariant i... |
I'm a computer programmer and I'm working on a truly unbreakable cypher and I keep going back to a book cypher (each letter of the message is referenced by a page,row,and column number in a random book where both the sender and receiver have identical copies.)
In my update we use data files and auto lookup. here is my ... |
I know that if the input size in a pseurandom-function is larger than its output, many different inputs will generate the same output by the Pigeonhole principle (I also read an article related to that).
AES with 256-bits key size in CTR mode will generate many equal outputs per IV across all the possible keys of such ... |
I'm curious if there's an encryption scheme where content may be encrypted to a public key where the associated private key can generate new decryption keys for the same content. The goal is to publish data that is encrypted with a server's public key and allow the server to produce new decryption keys as needed.
|
This is from Alan Rosen's video on Interactive proofs - https://youtu.be/6uGimDYZPMw?t=1754
Here the proof is that
the Verifier gets a random bit $b$ .
If $b = 0$, then Verifier gets a random $y \in Z^*_n$ & sends $z = y^2$ to the Prover.
if $b=1$, then the Verifier sends $z = xy^2$ to the Prover.
Now if $z$ is a ... |
I have the book "Handbook of applied cryptography". In there we have example for random tests.
I have bits sequence [11100 01100 01000 10100 11101 11100 10010 01001]*4 length on this sequence n = 160. And I need test this sequence in order to understand this sequence is random or not. And problem with understanding thi... |
I've been trying to use AES from OpenSSL and got to know that I need to use the EVP-based implementations rather than the AES_*.
I need to use AES-128 implementation to generate bitstreams, essentially passing various keys, and plaintexts to analyze the ciphertext generated for cryptanalysis of the algorithm. I went th... |
I have come across two supposedly identical definitions of lattices in the lattice crypto literature. There are mainly these two definitions of lattices, the first considers lattices as discrete additive subgroup and the second is the common vector space definition.
Definition 1: Discrete additive subgroup
$$\forall x ... |
Would it be technically possible to use hundreds of computer processors together to work on an algorithm like the Shor's algorithm and break RSA?
I've been reading about the crazy amount of qubits required to break RSA but what if hundreds of 64 bit processors work together towards the same goal? I would assume, if pos... |
If I have 256 bits of handwavium "perfectly random data" and I hash these 256 bits of data with a secure hash function (possibly SHA-256).
Could the resulting hash be considered "perfectly random data" as well? I am assuming the answer is "no", but don't know why.
What information / keywords would I use to find out mor... |
I am given a set of $(u, v)$ values, matrix $A$, primary key vector, private key vector, error vector and prime $q$. I wanted to recover the binary value of each $(u, v)$ pairs using LWE decryption.
The formula I used to get that was: $\mbox{result} = v - s u$, where $s$ is the private key. I then compared the result w... |
Some famous cryptographical protocols rely on the construction of graphs $G_i= (V_i, E_i)$ for $i=0,1$ that are not isomorphic. For the safety of this protocol, it is central that one can not easily verify that $G_0\not\cong G_1$. So, for instance, one could easily establish that $G_0\not\cong G_1$ if $|V_0| \neq |V_1|... |
Is there an implementation of Shamir's Secret Sharing that can be regarded as a "canonical" (or "reference" or "standard") implementation, so that I can test other implementations to be "standard compliant"?
The above question is pretty vague. I have more details in mind, but some of them might be misleading or based o... |
Given a cryptographic prime $p$ and a generator $g$ of $\mathbb{F}_p$, the Decisional Diffie Hellman problem asks us to distinguish
$(g^a, g^b, g^{ab})$ from $(g^a, g^b, g^z)$ for random $a, b, z$. This is an easy problem, because the generator has Legendre symbol -1, which allows us to differentiate between such tripl... |
I was reading about some way to imagine the signature of a message using the RSA problem :
Let $N$ be the product of two prime numbers $p$ and $q$. Let $s$ be
the signature of a message $s$ (provided that such $s$ exists) defined
as $s^x = x \bmod N$.
Later on the following requirement is made on $x$ : $x$ is prime w... |
Im trying to learn more about cryptography and ran into a post, Is AES-128 quantum safe?, which asks if AES-128 is safe. From the articles and replies it seems that AES-128 (symmetric key) is safe even with the advent of quantum computers (for now). However, it seems that asymmetric keys are not safe?
So, assuming you ... |
I am generating large prime numbers to create a cyclic group for ElGamal encryption, I can specify the bit-length n but want to limit the size because this will ultimately allow me to limit the amount of data passed through external channels.
Also the data being protected has an extremely short time-value vector meanin... |
I am reading a paper named Verifiable Random Function, written by Micali, Rabin, Vadhan in 1998. In Residual Pseudo randomness propoerty of a VRF, it is written that If T runs for at most s(k) steps, it succeeds in the experiment with probability 1/2 + 1/s(k).
I do not understand the exact meaning of s(k). If it is pol... |
Previous:
https://web.archive.org/web/20160102181336/developers.yubico.com/U2F/Protocol_details/Key_generation.html
https://www.yubico.com/blog/yubicos-u2f-key-wrapping/
$$
PrivateKey = \operatorname{HMAC-SHA256}(AppID+nonce, DeviceKey)\\
KeyHandle = nonce + \operatorname{HMAC-SHA256}(AppID, PrivateKey)
$$
Now:
https:... |
I am new to this encryption scheme, so I may not be exactly sure of its implementation.
I have a list of (u, v) ciphertext pairs to decrypt, each of them are 1-bit.
{ "u": [ 1, 19, 3, 2, 24 ], "v": 16 },
{ "u": [ 3, 20, 22, 26, 15 ], "v": 21 },
{ "u": [ 7, 3, 24, 26, 22 ], "v": 13 },
... |
I'm having trouble testing a not-so-popular algorithm that I haven't found an implementation of, so I wrote it myself and now I'd like to test it with nist tests, but I have a suspicion that I'm doing something wrong.
I got encrypted file with ~10,000,000 bits. I tested my algorithm in the following wayю.
I set the inp... |
I know I should calculate the multiple inverse of plaintext with ciphertext $\pmod {26}$. However, the problem I have is that the plaintext is a $3 \times 4$ matrix which is not square, so how would I get an inverse?
Should I get the inverse of one side (left or right) of the plaintext or is there another way?
|
In simulation based proof of cryptographic scheme, if k parties are invovled in the scheme, then k simulators should be constructed for all the parties？
|
I started studying CSIDH a few weeks ago and, seeing these papers [1] [2], I was wondering:
Given $[a]E$ and $E$, find $[a]^{-1}E$.
I read that is easy to find $[a]^{-1}E_0$ knowing $[a]E_0$ by quadratic twisting, but I haven't found any resources explaining how to compute $[a]^{-1}E$.
So, is it possible to compute $... |
When I look up who developed SHA-2 family, the result I get is along the lines of
SHA-2 was first published by the National Institute of Standards and
Technology (NIST) as a U.S. federal standard.
What I am really looking for is "Which individuals have developed SHA-2 family?". I understand, that most probably there ... |
I have an algorithm that encrypts large text. I want to test this algorithm on statistical tests. The ciphertext contains ~10,000,000 bits. I decided to test the algorithm in two different ways, I took the ciphertext and passed it to the input of statistical tests:
The first parameters were as follows: /assess 1000000... |
I am writing to request information about the difficulty of finding z in Z/pZ (where p is a large prime) given z^l and l. I am working on a project that involves this problem, and I am interested in learning more about its complexity.
Specifically, I would like to ask for your insights on the following:
Is there any k... |
I have a chat system where multiple clients communicate securely using Libsodium authenticated encryption.
Every client have their own 32 byte key pair. If two clients want to communicate they first share their public key out of band and then use e.g. crypto_box_easy for encryption.
I want to create a service that allo... |
These days I'm generating some PGP keypairs, and I'm struggling to understand the correct terminology behind ECC keys. Moslty in the differences between ed25519/cv25519/ECDSA/EdDSA/ECDH. I tried to check RFC 6637 and this RFC draft without being sure of what I understood.
Let's take a practical example, with RSA first.... |
secp256k1 is an elliptic curve $E$ over a prime field $\mathbb F_p$, of equation $y^2\equiv x^3+b\pmod p$, with prime order $n$.
I noticed† that the different curve $E'$ over the prime field $\mathbb F_n$ with the same equation has order $p$. The roles of $p$ and $n$ are reversed in $E$ and $E'$.
That also holds for se... |
LWE Encryption Scheme by Regev is inefficient due to its public key sizes in $O(n^2)$. This led to the variant problem RLWE, defined in this paper :
Let $n$ be a power of two, and q a prime satisfying $q = 1 \mod 2n$. We define $R_q = (\mathbb{Z}/q\mathbb{Z})[X] / (X^N+1)$, which is the polynomials with coefficients ... |
Naively, when one applies rounding to a uniform random value one anticipates that the change is uniformly distributed. In lattice-based cryptography, is there a formal notion or proof of equivalence between learning with rounding and learning with uniform error schemes?
Secondly has anyone proposed a dynamic version of... |
I'm trying to implement impossible differential cryptanalysis on 3.5 round IDEA using Miss in the Middle Attack on IDEA and Khufu paper as a reference and I'm stuck on the first two steps of the attack:
In the paper the authors say that I should choose a structure of $2^{32}$ plaintexts $X^1$ with identical $X^1_{2}$ ... |
I want to know if there's any algorithm to find the embedding degree of elliptic curve? for example SECP256K1 curve has embedding degree 19298681539552699237261830834781317975472927379845817397100860523586360249056. this number is so large that it can't be found using brute force. So there has to be an algorithm to fig... |
I'm implementing a digital signature algorithm for academic purposes using elliptic curves. I am familiar with equations of the form $$y^2 = x^3 + ax + b$$, but the paper I am reading for implementing point addition and doubling uses the equation $$Y^2Z = X^3 +aXZ^2 +bZ^3$$.
I guess the $Z$ comes from representing the ... |
If we have a (possibly imperfect) cryptosystem that generates ciphertext $C$ from plaintext $P$ and key $K$, we have:
$H(C, P, K) = H(C | P, K) + H(P, K)$
where $H$ is entropy.
My question is why following is true:
$H(C | P, K) = 0$
It seems because each key and plaintext uniquely define a ciphertext but I want to ... |
I am studying about RP-algorithm from the book Algebraic Aspects of Cryptography by Neal Koblitz.
The following example is given in the beginning which is the Probabilistic Primality Test.
I understand the scheme of the algorithm but I am facing difficulty in understanding and deducing the probability that given the n... |
I've been given that an attacker has a 2-Key Triple DES Cracker that is capable of performing 10$^{24}$ encryptions per second and have subsequently been asked how long it must take before the attacker successfully finds the correct key.
This doesn't seem too hard however I'm caught between two different answers, here'... |
A vigenere cipher is just a ceasar cipher (ROT13) based on a SECRET word from my understanding. Are there variations of a vigenere cipher that are similar? I want to create a new type of vigenere cipher where the SECRET is used 2-3 times. Once forward for encrypting it once, then a second time encrypting it twice with ... |
Are ideal functions and leakage collections the terms of UC security? Why I often see them in a simulation-based proof under stand-alone model? Some papers use the definition in Lindell's How to simulate it? while defining ideal functions (sometimes with leakage collections), which really confuse me a lot!
|
Is there a non-deterministic encryption scheme that is vulnerable to a CPA? I got asked this in an interview and I answered with no but the interviewer said that my answer is wrong. Would somebody clarify if this is possible?
|
On 6 March, Yi Lee sent over the NIST mailing list an announcement of their submitted paper that found a flaw in the original security proof for Dilithium. In their manuscript, they fix the proof on paper, and they also verified whole proof using EasyCrypt. URL: http://ia.cr/2023/246
In Section 3.2, paragraph "The ‘Pro... |
Given two numbers $x_1$, $x_2$ and their respective binding numbers, $b_1$ and $b_2$, let's take their Pedersen Commitment to be $C(x_n, b_n)$ $\forall n=1,2$.
What is $C(x_1 * x_2, b_1 * b_2)$?
|
I want to encrypt Bluetooth Beacon data. I was wondering if having very little entropy in the clear text would make the key easier to guess?
The maximum data length is 31 bytes
An example of the data (packed struct):
where sequence monotonically increases, all other measurements have small variations between readings (... |
I would like to use JWT but one thing I'm still thinking is ¿what is the best length for the secret?
If I'm using HS512 as a signing method the secret should have a length of 512 bits as far as I understand and I imagine that 512 bits are 64 characters (of 1 byte) because the secret is a string, as far as I understand.... |
Given two field elements as input of Arithmetic Circuit (consists of adding gates and multiplicating gates only), how could I output the bigger one? Or, how to place the gates in order to distinguish which one is bigger (using Arithmetic Circuit)? Could you please describe the method in picture?
In Zero-knowledge Proof... |
Several texts talk about malicious/dishonest verifiers in a zero-knowledge interactive proof but none of them properly detail how a dishonest verifier can gain extra knowledge over an honest verifier using some examples like "Quadratic Residue Interactive proof" or "graph 3 colouring Interactive proof".
I went over the... |
I am making an implementation of Niels Ferguson's paper: Single Term Off-Line Coins in Python.
In the Coin withdrawal protocol, in the last steps, Alice checks that the signatures she received are correct. She checks if she needs to adjust the signatures by making corrections. When I run the program I get most of the ... |
I'm having troubles in interpreting the output of the SUPERCOP benchmarks of some digital signature schemes.
Precisely, I don't understand how to read the number of cycles for the key generation. This should be found in the line of the SUPERCOP output file with the keyword "keypair_cycles". However, I find three such l... |
I was reading this paper, where I came across the following statement:
We consider the problem of unbounded MPC with security against semi-malicious adversaries in the dishonest majority setting. In our communication model, parties publish their first message through a broadcast channel which is immediately delivered ... |
From section 4.4 of this book https://www.ic.unicamp.br/~rdahab/cursos/mo421-mc889/Welcome_files/Stinson-Paterson_CryptographyTheoryAndPractice-CRC%20Press%20%282019%29.pdf
I'm confused on how the differential trail is formed given they don't know the round key. I would love if someone could give a clear example of how... |
I was reading this paper, where I came across the following statement on Pg 4 under the Homomorphic Commitments:
A witness encryption scheme, associated with a
NP language, consists of an encryption and a decryption algorithm: Anyone can encrypt their message µ
under an NP instance and the decryption algorithm can obt... |
In SMhasher, it seems that data (keys) are read one by one sequentialy, and not splited and:
MiB/sec: The average of the Bulk key speed test for alignments 0-7 with 262144-byte keys. The higher the better.
/\ This is written in its README.
The author said that are the output of hash functions that is measured.
Take a ... |
We have the RSA function:
$c = m^e (mod n)$.
I would like to know the proof that there is not an $m_1$ and an $m_2$ message that produce the same $c$.
My thoughts:
We know that $m \le n$, so $m_1 \ncong m_2 (mod n)$.
We also know that if $a \cong b (mod n)$, then $a^k \cong b^k (mod n)$.
So if $m_1 \ncong m_2 (mod n)$ ... |
Let $\mathbb{F}_q$ be a finite field of odd characteristic. I know that a constant-time implementation of the square root extraction $\sqrt{\cdot} \in \mathbb{F}_q$ is used in the context of hashing to elliptic curves (see Appendix I of the draft).
Are you aware of other cryptographic contexts in which a square root $\... |
Bob has two detectors + and x. You can see it in the picture I sent.
Alice sends a photon with vertical polarization and Bob uses the + detector and the detector is detecting Alice's photon.
Bob's + detector detects when the polarization of the photon from Alice is either vertical or horizontal. (because it is + detect... |
An adversary is able to insert a random string (which he does not control: he can only randomly generate it and insert it). The random string is parsed by the victim as an ECDSA public key. This public key is used to verify a signature (the adversary can insert whatever signature he chooses). Is this a vulnerability? E... |
I'm implementing impossible differential cryptanalysis on AES and I've started with implementing it on mini-AES to fully understand the process using R.Phan's paper as a reference.
But I don't understand the initial pairs preperation step:
In the paper the author say to obtain $2^{13}$ plaintext $P$ and another $2^{13... |
If understood right, CMAC is not quantum-safe because it relies on AES-128 (which isn't considered as quantum-safe), while HMAC is, because it relies on SHA3 (which is considered as quantum-safe). Did I understand this right?
|
I'm having trouble understanding how time complexity of trial division is exponential.
If it takes $\sqrt n$ tries to factor $n$ in the worst case scenario then time complexity is $\mathcal{O}(\sqrt n)$, which I thought would mean that the number of operations grows slower than the increase in the number of inputs. So ... |
In the AES proposal, the last sentence on page 30 it is said:
To be resistant against LC, it is a necessary condition that there are no linear trails with a correlation coefficient higher than 2^(n/2)
I know that the correlation coefficient can have values in the range [-1,1]. Moreover, In the same proposal, they men... |
Suppose the correctness requirement of private-key encryption scheme is now relaxed to require only that
$$
\Pr[Dec_k(Enc_k(m)) = m] \ge \frac{1}{2} + \epsilon.
$$
Prove of disprove that if an encryption scheme satisfies the perfect secrecy and the relaxed correctness, then $|M| \le 2|K|$, where $M, K$ are the message ... |
I was recently trying to perform a AES-128 CTR Encryption and Decryption.
I had a observation that if a AES-CTR encrypted value is encrypted again (with same key and Iv) it results in the plain text that was in encrypted in first place.
Just want to the reason behind this and does any other AES scheme support this simi... |
I am using Montgomery ladder with Montgomery curve $by^2=x^3+ax^2+x$ using XZ coordinates and I recovered the $X$ value using $X3=X1/Z1$, but I don't know how to recover the $Y$ coordinates.
for Double and add ladder I am using this:
A = X2+Z2
AA = A2
B = X2-Z2
BB = B2
E = AA-BB
C = ... |
As detailed in the paper Statistical test suite for random and pseudorandom number generators for cryptographic applications by NIST, the first test is given as a basic significance test, it uses a bit sum and calculates the p-value and test statistic. But I do not have the clearest understanding of why $S_{obs}$ is de... |
Is it insecure to sign the plaintext 0 with ElGamal signature algorithm? Can this leak the private key, give the possibility to forge other signatures or does provide any other attack vector?
|
One experienced user of this forum said: "The key is the input of the hash function to build up a fast internal hash table. The key is hashed again to perform the lookup.".
If I hash a data such as a 262144-bytes seed (as SMhasher does) is passed through a hash function to build up a fast internal hash table, can the s... |
When I try to generate decimal numbers in the range 0-18446744073709551616 using a hash function I always get big numbers like this:
$ A=$(date | b2sum -l 64 | awk '{ print $1 }'); echo $(calc 0x$A)
16324260068905187599
$ A=$(date | b2sum -l 64 | awk '{ print $1 }'); echo $(calc 0x$A)
5500525113920202581
$ A=$(date | b... |
In Crystal Kyber specification, page no10, there are 3 algorithms namely KYBER.CCAKEM for making the CPA-secure Kyber into CCA-secure one.
Q1: How is the shared key K being generated in KYBER.CCAKEM.Enc & KYBER.CCAKEM.Enc related to the CPA-secure algorithms ?
Q2: Is the shared key K used as input parameter of sorts, f... |
Due to protocol limitations, I can put in 24 bytes of data only for tx (excluding headers), if I use AES_GCM for encrypting my data, I understand I don't need to worry about padding.
For instance, if my data is 22 bytes, I would be getting a 22 bytes encrypted output. So, I had zero-ed in on AES-GCM or AES-CTR. However... |
In TCS, functions need to be converted into boolean circuits.
So is this Boolean circuit a combinational logic, i.e. a directed acyclic graph, satisfying the topological order?
I would appreciate your answer. Thanks!
|
In the encryption process, the ciphertexts c1 and c2 are added to errors e1 and e2 each to get noisy ciphertexts u and v.
c1 = A * r
c2 = b * r + m * (q/2)
u = c1 + e1
v = c2 + e1
However, choosing a random value for e1 and e2 would cause u and v to not match to its message m. Wikipedia and several research papers su... |
I am working with hardware that can only encrypt with AES. The problem with this is that the message must be publicly verifiable, without the encoding key being exposed. This is the textbook use-case for asymmetrical keys, yet the hardware does not support this. I cant come up with a method myself where a message is en... |
I recently read a paper that proposed a matrix-DDH which is a matrix variant of DDH assumption. The brief definition is follows:
Let $G$ be a group of prime order $q$.
Then, the matrix-DDH says that it is hard to distinguish between two distributions:
$\{[A], [A\cdot w] \} \approx \{[A], [u], u\leftarrow \text{random} ... |
Cant you look at the algorithm used to encrypt and find the private key from the public key that way? As an example, here's a simple python algorithm that encrypts an input:
rnd.seed(int(pasc))
return [(tran_ltn[content[i]] + rnd.randint(400, 1400)) for i in range(len(content))]
This is obviously symmetric. However, i... |
I'm a novice reader of Introduction to Modern Cryptography, where it states:
Let $G$ be a pseudorandom generator with expansion factor $\ell(n) > 2n$.
In each of the following cases, say whether $G′$ is necessarily a pseudorandom generator. If yes, give a proof; if not, show a counterexample.
(a) Define $G'(s) = G(s_1... |
I am attending the video lectures from Prof Dan Boneh. He gives the following example.
Let $G:\mathcal K\longrightarrow \Bbb Z_2^n$ be a PRG with the property that from the last $\frac{n}{2}$ digits of $G(k)$ we can easily compute the first $\frac{n}{2}$ digits of $G(k)$. We want to show that $G$ is predictable for som... |
I am working on using the Hadamard transform as a way to map randomly generated values and then apply statistical tests as defined by Nist or other institutions. One resource online I found particularly helpful, yet I do not seem to have the mathematical intuition to understand some parts. The python code and the text ... |
I'm using AES-256-CBC to encrypt password for a set of users, and for each user in the database we gotta generate and store the password in the database. The database has constraint that the name of the user must be unique, so I was wondering if using the name of the person as the initialization vector was okay, becau... |
My question might be a duplicate but I wasn't able to find a similar question.
I recently developed a wallet-like app and I am trying to implement some MPC features.
I searched a little and even asked ChatGPT about how I can achieve that.
I know how ECdsa and how Shamir’s secret sharing work but I can't find a way to c... |
I am following this paper Encryption from Learning with Errors for the generation of errors e1 and e2 to retrieve the ciphertext u and v as described below.
u = Ar + e1
v = br + m (q/2) + e2
For this text:
We require for this algorithm to work that the χ distribution has a mean of zero and, with
overwhelming probabil... |
In ECDSA, when parsing the public key a test is made to ensure the public key really lies on the curve. What vulnerabilities appear if one does not do this?
|
Consider the following paper based OTP
Plaintext has 11 possible symbols 0-10.
$C_i = M_i + K_i\ mod\ 11$.
$K_i$ comes from a pre-shared key material which is never reused.
How to introduce data integrity/ MAC in it which can be calculated using pen & paper.
|
Because of the need of the project, I want to develop a simple public key cryptography algorithm, but I have doubts when generating the key pair.
I have learned about the key generation process of RSA. It is to prepare two coprime numbers (p, q), multiply them to obtain N, and then calculate L (that is, L=lcm (p-1, q-1... |
I'm trying to find a MD5 hash collision between 2 numbers such that one is prime and the other is composite (at most 1024-bit). I'm using fastcoll with random prefixes for each iteration.
For this I wrote this script:
import subprocess
from Crypto.Util.number import bytes_to_long, isPrime
import string
import random
w... |
Consider the following two verifiable encryption schemes for Discrete Logarithm.
FS01: “One Round Threshold Discrete-Log Key Generation without Private Channels” by Pierre-Alain Fouque and Jacques Stern,
Section 3.2, "A Proof of Fairness".
CS03: “Practical Verifiable Encryption and Decryption of Discrete Logarithms” by... |
Consider a single hash table containing digests from about 10 different 256 bits cryptographic hashing functions, like SHA256, SHA3, KECCACK256, BLAKE2, BLAKE3, etc...
Is such table still considered collision resistant?
I am inclined to think so, but I might be missing something.
|
I'm looking for a general comparison of encryption algorithms in regard to Confusion and Diffusion (as defined by Claude Shannon),
and if possible, specifically for their SAC and BIC quality.
For example, xor-streaming ciphers have no (0, zero, zilch) diffusion - you switch 1 bit in the ciphertext, you know which singl... |
For context, I'm making a non-production grade reference implementation of the balloon hash function using the Web Crypto API. In order to make it less susceptible to certain attacks on common memory hard KDFs, the number of memory blocks should be reduced, meaning their size should increase. I am however restricted in... |
I haven't seen Threefish widely used.
For example, I've seen Twofish used in file encryption software, even though it was not standardized, but I've never seen Threefish.
Are there security issues?
|
I'm currently going through the book "Guide to Elliptic Curve Cryptography" by Darrel Hankerson, Scott Vanstone, and Alfred Menezes. In the book, the authors state that
[…] there is no mathematical proof that the ECDLP is intractable. That is, no one has proven that there does not exist an efficient algorithm for solv... |
Lets say entity A sends a secret "token" to anybody that they trust.
The token itself is the proof and its sent equally to everybody and it has or needs to be derived from application specific data.
Entities B, C and D get the same token and want to publish a timestamped event for proof, but they don't trust anybody, e... |
The padding fix by Albertini et al. for AEAD key commitment (pp. 3292 and 3301-3302) involves prepending a block or two of zeros to the plaintext before encrypting. After decryption, these bytes are checked to be zero to verify that the same key was used for decryption.
The Counter-then-Xor (CX) construction by Bellare... |
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