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How many distinct sequences can a $128$-bit Fibonacci LFSR (considering $4$ taps set for the maximum period) generate? Will all $2^{128} - 1$ distinct seeds produce distinct sequences?
Also, let's say I discard the first $128$ bits and only consider the bits that occur after the MSB of the seed has come out of the outp... |
Can the KangarooTwelve Keccak-p[1600,12] be used to create a CSPRNG in which there is random access to an element (or a small group of outputs) of the generated list (instead of sequential generation)?
Perhaps the k-th group of L outputs can be generated as:
K12(inputMessage=seed || k, customizationString="",outputByt... |
We want to implement an encryption / decryption module that we want to provide to different internal components of our system (internal library for internal components).
The component will provide (authenticated) Encryption & Decryption based on state-of-the art algorithms (AES-GCM-256).
Furthermore we have a Password ... |
I try to understand the POODLE attack. I read that the attacker try to change one byte of the last block of the ciphertext. Becasue the last block is only have padding and the last byte is the padding length the attacker need that only the last byte remain the same. I understand how the attacker know if it stay the sam... |
Why is the Initial Permutation Step necessary in DES? How does it strengthen the cipher since we are reversing the permutation in the output?
|
I am trying to implement a TRNG on Windows and among other entropy sources, I want to extract raw bytes from various kinds of CPU and process info.
As per my knowledge, BCryptGenRandom is a CRNG in the Windows API that uses this kind of noise to generate entropy. Do files like /dev/random exist on Windows and if so how... |
May I ask that in section 2.7 challenge space in the paper Lattice-Based Zero-Knowledge Proofs and Applications:
Shorter, Simpler, and More General
What is rot(c), why does rot(c) $\in Z^{d*d}$, and why |rot(u)|2 <= |u|2 ?
And may I also ask that what is $S_{k}^{\delta}$
Also, I am new to lattice crypto, I would trul... |
I'm currently studying the possibility of a novel ransomware technique, where an adversary instead of forcing the victim to pay a ransom, forces them to brute force a key of given length and thus spend a lot of computational power.
However before beginning the victim would need some assurance that recovery is actually ... |
According to my understanding a public key is made up of x and y coordinate and a compress public key is made up of the y-coordinate since it's possible to directly calculate the uncompress public key using the compress public key.
Using the below secp256k1 elliptic curve coordinate what formula can I use to derive the... |
I'm trying to figure out why Mersenne Twister use exactly Mersenne prime numbers but not regular primes. What makes Mersenne prime numbers more appropriate for this role than regular primes?
|
Background information:
I need to encrypt 168bit messages, the ciphertext should, preferably, match the plaintext size. Message Authentication and Integrity is not a must, but a really important should. My first idea was using AES-GCM-SIV, but performance is a thing. the software will run on a mini PC (Older RaspberryP... |
I'm researching cryptographic libraries for a project I'm working on, and I'm particularly interested in the BearSSL Library due to its lightweight nature. But I'm not sure if it supports ECC (Elliptic Curve Cryptography) encryption/decryption functionality.
Can someone provide information on whether the BearSSL Librar... |
Sorry, this is sort of a beginner question.
But providing that it is possible to find the same options, can I verify a message with Openssl if it was sign with .Net System.Security.Cryptography ?
Let's say I need to do this for sha1, are the underlying algorithms similar enough to be able to verify the signature of ano... |
Suppose we have two sets of ElGamal cipher texts encrypted with the same public key $y$ in a prime order group:
$C_i = (g^{r_i}, a_i y^{r_i}) $ for $ i \in \{1 ... n\}$
and
$D_j = (g^{s_j}, b_j y^{s_i}) $ for $ j \in \{1 ... m\}$
Bob own the private key $x$ to $y$ such that $g^x = y$
Alice wants to know if there is any... |
Here is a CTF chanllege about RSA(The competition has ended for serval hours),and here is the critical encryption code:
.........
def encrypt(msg):
p, q, r, t = getPrime(256), getPrime(256), getPrime(256), getPrime(256)
n = p ** 2 * q * r * t
phi = (p - 1) * (q - 1) * (r - 1) * (t - 1)
privkey = inverse... |
Various papers in the literature (such as https://eprint.iacr.org/2022/322.pdf, https://eprint.iacr.org/2013/850.pdf) use the sign, exponent, and significand values to additively secret share the original floating point secrets and later perform arithmetic operations on the shares of sign, exponent, and significand val... |
Quote from https://en.wikipedia.org/wiki/RSA_(cryptosystem)#Operation
A basic principle behind RSA is the observation that it is practical
to find three very large positive integers $e$, $d$, and $n$, such
that with modular exponentiation for all integers $m$ (with $0 ≤ m < n$)
$$ (m^e)^d \equiv m \pmod{n} $$
and that... |
$\left(\epsilon,\delta,\gamma\right)$-Random Differential Privacy as defined in rubenstein17:
$$\begin{align*}Pr\left[\forall S \subset \mathbb{R}, Pr\left(A(D) \in S\right) \leq e^{\epsilon} \cdot Pr\left(A(D') \in S\right) + \delta\right] &\geq Pr\left[|f(D) - f(D')| \leq \Delta\right] \\ &\geq 1 - \gamma\end{align*}... |
Setting all 48 ChaCha state bytes (key, nonce, initial counter) from one result of strong hash function like sha3-384 or blake2b - correct usage? or bad practice?
PS: using original chacha20 (8bytes nonce/8bytes counter) for encrypting one long file or one-way tcp stream, not multiple small files/messages.
|
I am currently working on a cryptography challenge. The program uses AES-GCM to encrypt and decrypt strings.
Let's say I have the following:
IV which is reused
only 1 cipher text
authentication tag
AAD data
Is it possible to uncover the plaintext even if I don't have the key? I've read somewhere that IV reuse is bad ... |
Suppose I have the following secret, calculated by concatenating and hashing the results of two random strings:
secret = H( H( random_string1 ) || H( random_string2 ) )
Let's assume that the adversary knows one of these strings but not the other. In this case, can the adversary recover the secret in a practical manner?... |
Assuming there is a web service that returns the following to an unauthenticated user:
SHA-1(known_prefix + user_input + backend_secret)
where + is string concatenation, known_prefix is known to the attacker, user_input can be specified almost arbitrarily (maybe only printable ascii characters, but arbitrary length), ... |
A Boolean cardinality constraint
$$\sum_{j=0}^{n-1}x_j=k,$$
where $x_j$’s are Boolean
variables, and $k$ is a non-negative integer.
How to express the Boolean cardinality constraint to CNF formulas?
|
Suppose I encrypt a file, of, say, 10 MB, with a secure, suitable passphrase, and the command:
gpg --symmetric my_file.txt
What level of expertise and hardware would be required, in broad terms, to break the encryption?
|
I'm diving into SHAKE256's XOF (Extendable Output Function), and I've got a bit of a head-scratcher.
I'm wondering if there's any difference between incrementally absorbing bytes and absorbing everything in one go when it comes to generating the digest. I've scoured the web but couldn't find an answer.
Scenario 1 Incre... |
In this question on sha1(known_prefix + user_input + backend_secret), an answer states that is realistically possible to find the first few bytes of backend_secret quicker than brute force.
Changing only user_input, how can I find some information about the constant value of backend_secret?
I give the known prefix of ... |
This assumption appeared in the 2000 'timed commitment' to justify privacy in the scheme. But it is not known what the relevant symbols mean in this hypothesis.
|
I have $C_1 \oplus C_2$ where $C_1$ = $AES128_k(P_1)$ and $C_2$ = $AES128_k(P_2)$.
I know the k, it is 0 (i.e. 16 bytes of zeros).
I know the piece of $P_1$ (7 bytes).
How to restore the plaintexts ($P_1$, $P_2$), knowing all this?
|
Hi im doing a problem from the Chapter Lightweight Introduction to Lattices in "Learning and Experiencing Cryptography with CrypTool and SageMath"
I'm curious if my implementation is wrong since I'm trying to measure a solution as a whole number as opposed to fraction. I've tried searching for common leetspeak words li... |
I have trouble finding information on the security strength of HMAC-SHA256 against key recovery attacks with respect to the key size.
To fit a certain application I must use a 128-bits key with a HMAC-SHA256 function. All the documentation I read about HMAC-SHA256 advise or impose a 256-bits key, but the reason given f... |
Use a block cipher in CBC mode with a public or all-0 key. Twice.
Wrapping the last block into (xor) the first on the second round.
Every block will depend on all previous and all successive blocks. Any corruption in any block will corrupt all the rest.
Will this result in an All-Or-Nothing Transform (AONT)?
|
I've been sometimes getting this error while interacting with zksync "invalid value.blockHash" and have been unable to find information about it elsewhere. What's curious to me is that it only happens sometimes, not all the time and it also happens with different smart contracts interactin in zksync that belong to diff... |
In TLS 1.3, and since the server signs the entire handshake messages including the server hello message, in this case, is the SNI extension of the client hello message, is it included in the content for which the signature is generated. I know that the cipher suites exchanged are signed, but not sure about the SNI.
|
In PHOTON-Beetle Authenticated Encryption algorithm, the state consists of 64 4-bit
elements, which is represented as a (8 × 8) matrix. The Initial Value which consists of Key and Nonce from the specification is $IV \gets N||K$. Can anyone guide me how this 256-bit $IV$ sits on the state matrix?
For example Key is $0x0... |
I implemented AES128-CBC algorithm and what I need is to be able to compare encrypted text without decrypting. Is the only way to use static or no iv to achieve this? . Any ideas?
Use in code -Something like :
select x from ins left join Users ui on ui.UserIDNumber=id
or Select * from users where userIdNumber = @userI... |
Short version:
Given a hash of a plaintext, a public key, and a ciphertext (but not knowing the original plaintext), is there any way to verify that the ciphertext is the plaintext after being encrypted with the public key?
Long version:
I'd like to develop a broker that can pass to a recipient a message of which it kn... |
Can we use array as the input of a transition/function? Just like:\
transition testarr(arr: [u32; 3]) {
}
I saw some tutorials that have examples of this but now the Aleo seems not to support this grammar.
|
Suppose I have a masked AES encryption $AES(\oplus_i K_i, \oplus_i P_i)=\oplus_i C_i$, i.e. the key, plaintext, and resulting ciphertext are tuples $K_i$, $P_i$, and $C_i$ that sum to $K$, $P$, and $C$ respectively, and the encryption acts independently on the randomized input shares to the extent possible to produce t... |
I'm new to cryptography, and I'm working on exercises that involve "breaking" PRF schemes which involves writing a poly-time program that distinguishes between two particular programs, the ideal random world and the fake random world. Basically, I need to write a poly-time program that "wins" a distinguishing game by d... |
Background: there is a theory going around that claims that P256 was backdoored by the NSA. The theory goes is that the NSA found a weakness that applies to a nontrivial fraction of elliptic curves (perhaps one in a thousand, perhaps one in a trillion). So, what the NSA supposedly did is use a published procedure to ... |
I've been thinking about ways to improve the security of my data stored and backed up using the "3-2-1" method.
Moreover by using several layers of encryption to encrypt and decrypt a filesystem structure steps by steps.
Consider the following :
/root
|____folder1
|____folder2
|____subfolder1
|____subfolder2
... |
Gaussian distribution on lattices generally seems esoteric (at least for me, for now). My question is:
Does Gaussian distribution on a lattice mean to add a Gaussian noise on a single point of a lattice (or its span) or adding Gaussian noise on all points of a lattice?
When we are reading a paper,
in some part of the ... |
Bob has constructed a non-linear function $f: \mathbb{R}^n\rightarrow \mathbb{R}^m$ of moderate complexity (i.e., evaluation takes on the order of seconds on a modern computer). Is it possible to share a function $g: \mathbb{R}^n\rightarrow \mathbb{R}^m$ of the same asymptotic complexity with Alice, such that:
(1) $g$ ... |
I want to sign and transmit a short message, which contains a few simple hashes. My objective is not to prevent an attacker from inserting a fake message, but to ensure that the attacker cannot define or craft the specific contents of such a fake message.
The conventional method involves creating a signature by first h... |
I'm implementing encryption in my browser extension that will allow users to encrypt their data and then share them with others. And since shared links can be leaked, I want to protect the data as much as possible against brute force attacks.
I'm using PBKDF2 to derive 256 bits:
self.crypto.subtle.deriveBits({name, sal... |
In TLS 1.2, when client authentication is carried out, digital signatures are utilized. However, at what point is the specific signature algorithm communicated to the server? It seems to me that the server cannot perform verification without receiving a unique algorithm from the client.
From what I understand, what is ... |
In the Wikipedia page on differential privacy, the section on $\varepsilon$-differential privacy for the Laplace mechanism says that the Laplace mechanism is specified for some output as $\mathcal{T}_{\mathcal{A}}(x)=f(x)+ Y$, where $Y = (Y_1, \ldots, Y_n)$ and the $Y_i \sim \mathrm{Lap}(\lambda)$. Here's my question: ... |
I've implemented a CTR_DRBG random number generator according to NIST SP 800-90A Rev. 1 and I am now testing it with test vectors provided in NIST CAVS 14.3 (drbgvectors_no_reseed\CTR_DRBG.txt).
Starting from the very first example of [AES-128 no df]:
[AES-128 no df]
[PredictionResistance = False]
[EntropyInputLen = 25... |
I want to implement authentication for an API and thought about using Shamir Secret Sharing to do so.
My plan is to generate 1 Master Key which is stored in the Database, we then generate about 1000 Subkeys or more with the key threshold of 2.
1 of the subkeys is then also stored in the DB and will be used as the Appli... |
Assume we have the situation that Alice is receiving somewhere in the magnitude of 1_000_000 encrypted messages, whereby a small number (n<100 for 99% of cases) of these messages are meant for her. An outside observer should not be able to tell which of these messages are meant for Alice, so we can't just send the ciph... |
I am trying to implement an encryption function that uses the AES T-Tables implementation.
I am quite sure that my roundKeys are correct.
I also know that the initial round key addition in the following code is correct.
So there must be an error in the main rounds, but i am not sure what went wrong. I have narrowed it ... |
Can we have an asymmetric key in AES? Clarification about PBKDF2 and AES-GCM in WebCrypto
According to wikipedia AES page, AES is a symmetric-key algorithm.
The algorithm described by AES is a symmetric-key algorithm, meaning the same key is used for both encrypting and decrypting the data.
While PBKDF2, always acco... |
I was reading this post and the accepted answer wrote about a way to “prove that some list of points $[A,B,C,...]$ when multiplied by $x$ produces $[A′,B′,C′,...]$”. However, in their explanation their definition of $e$ seems to be self-referential. If you understand what they were getting at in that post, I'd apprecia... |
At page 336 in "Handbook of Applied Cryptography - Menezes", I see the sentence
For $n$-bit MAC with $t$-bit key space this requires $2^t$ MAC operations, after which one expects $1+2^{(t-n)}$ candidate keys remain".
I do not understand why is $1+2^{(t-n)}$. According to me, it must be $2^{(t-n)}-1$.
For example, in ... |
Are there any encryption protocols or services that are time based. I.e I can encrypt something now and it can only be decrypted on or after 01/01/2100. Like a digital time capsule.
The only way I can think that this could be implemented is by a third party that publishes a list public keys - one for each future day an... |
The following context is based on elliptic curves in short-weierstrass form y^2 = x^3 + b.
I know that elements of a non-prime order cyclic group G can be moved to its subgroup H by a process called "cofactor clearing". You just have to simply multiply a cofactor by an element of main group that ends up giving an eleme... |
Given two lattices $L_1$ and $L_2$ represented by bases $B_1$ and $B_2$, is there an efficient algorithm to compute $L_1\cap L_2$?
I can show, I think, that if $\gcd(\det(B_1),\det(B_2))=1$, then $B_1adj(B_1)B_2$ generates $L_1\cap L_2$, but I'm interested in lattices whose volumes have greater GCDs.
A follow-up questi... |
I need to design some protocol where actors will leverage Zero Knowledge Proofs (ZKP) to prove that they know the pre-image of some specific SHA256 hash without revealing the pre-image itself.
Ideally, they should also be able to batch proofs of multiple hashes into a single ZKP.
SHA-256 hashing is not a ZK friendly op... |
What are the theoretical usage limits of Kyber and Dilithium? Are there any sources to back this up? Maximum number of encryptions/signatures allowed per key, etc.?
|
Suppose we have $GF(2^{128})=F_2[x]/(x^{128}+x^7+x^2+x+1)$ and $a,b,c \in GF(2^{128})$ with $a*b=c$, where * is multiplication in $GF(2^{128})$. Could we convert them to $a',b',c'$ of length 128 bit vectors, such that $a'\&b'=c'$, where & is bitwise AND?
I think FFT might work, but I am confused how to do a FFT on a le... |
I have a question in regards to a task I've been given at uni. I need to encode the string 'Cyber' 2 characters at a time with RSA with padding being space.
What do the chunks look like than need to be encrypted? Should I just concatenate the ascii codes 'Cy',then 'be',then 'r ' , ex 'Cy'=67121, or should I separate th... |
I recently started reading about Yao's Millionaires' problem. If the Yao's Millionaires' problem is capable of finding if one party has less money / more or equal money than the other party, then is it possible for one party to find the exact amount of money that the other party have?
I specifically read the articles p... |
I am looking for a safe and easy way for my inheritors to get a password after my death. That can be the password of a digital vault, a password manager, or anything else.
I could write the password in a testament but since a leak is still possible, I do not want this to be in clear. I was thinking to encrypt the pass... |
The following context is based on elliptic curves in short-weierstrass form y^2 = x^3 + b.
pls read carefully-
I am looking for a function/formula/algorithm that can be applied on any curve, say for e.g. y^2 = x^3 + 2 with prime = 1097, largest subgroup order(J) = 1098 and subgroups = 1098, 549, 122, 183, 366, 61 and s... |
As a preamble,I acknowledge that it is fundamentally impossible to authenticate
that a networked client is who they claim to be. The question is, given that
it's impossible, what should I do anyway?
Suppose I have a http server and only want to provide services to browser X rather
than all the other brands of browser... |
I'm working on finding an attack on textbook RSA using non-prime, low public exponents $e_1,e_2$ for each encryption.
Given $$c_1 = m^{e_1}\space mod \space n \\ c_2 = m^{e_2} \space mod \space n$$
I found there's the Common Modulus Attack which works when $gcd(e_1,e_2)=1$.
But is there a different way to solve the pro... |
In my idea, $n$ clients will have the connection to a server, and clients will not be able to connect with other clients. Are there any previous design has been published to let $n$ clients agree on a same shared secret, while the server does not know what the secret is?
|
Assume I am using the SIMD encryption of homomorphic encryption. Performing plaintext-ciphertext multiplication between two vectors $\mathbf{a}$ and $\mathbf{x}$ means
$Dec(\mathbf{a} \times Enc(\mathbf{x})) = \mathbf{a} \times \mathbf{x}$, where $\times$ means point-wise (or say element-wise) multiplication. I am won... |
The situation:
I have a group with 20 members, each member broadcasting 1 message per second. Communicating one on one is possible, but 1 message per member per second is the absolute limit and every member needs every message.
The only means of communication for this group allows me to send 258 bits per message. The m... |
I need to store a public key in a variable of maximum 32 bytes.
I recover the compressed key and remove its prefix, but then I have to do the opposite: I have to rebuild the compressed address from it without the prefix.
I know that the prefix depends on the last two characters of the uncompressed key.
Prefix = 0x03 if... |
I used to think that adding random padding to an rsa plaintext was to prevent attack when you can ask/have access to different ciphered output, and decipher it without access to the private key (under certain conditions).
I've came across a signature verification scheme that seems to use random padding (at start and en... |
I'm studying a case where when i sign a same message with the same private key and a different nonce, i sometimes get signatures (r,s) where r values share some similarities (same numbers at the same indexes).
import ecdsa
import random
import sys
import math
from Crypto.Util.number import bytes_to_long
from ecdsa.numb... |
I have seen that Filecoin performed a public set-up ceremony for their zkSNARK system. Because Filecoin uses the Groth16 prover (which has a circuit-specific set-up), the output of this ceremony was public parameters that anyone can use to prove statements involving one of six Filecoin-defined circuits.
It would be nic... |
I just tried to implement ISAAC from scratch, using the Jean-Philippe Aumasson paper from 2007 as a reference.
This paper gives a definition of the original ISAAC algorithm as well as the improved ISAAC+ algorithm.
JPA states in this paper that there are several flaws in ISAAC, and that ISAAC+ would fix those.
However,... |
The BSI (Federal Office for Information Security in Germany) has published a paper detailing the requirements of cryptographic modules for certain applications in the energy sector: Key Lifecycle Requirements.
The paper describes the various requirements for hardware security modules but also includes software based cr... |
I just noticed that the FSE 1996 conference paper which defines ISAAC mentions a counter variable cc.
This variable is said to be the reason why ISAAC has a guaranteed minimum cycle length of $2^{40}$.
However, no-one seems to have noticed (until I did just now) that the algorithm does not use the cc variable for anyth... |
Using TR-31 key exchange, how is it possible to use restrictive modes of use, such as V (Verify only)? If Alice were to generate such a key, and send it to Bob, Bob would not be able to generate a MAC for Alice to verify. Can this be solved without leaving the safe bounds of Key Blocks?
To be specific, I am referring t... |
So I'm reading this article where they talk shortly about pseudo random generators where I'm not quite familiar with some of the notation. They call $\lambda$ the security parameter.
"Pseudorandom function (PRF). Let $\mathcal{F}=\left\{F_{\text {sk }}:\{0,1\}^{\ell_1(\lambda)} \rightarrow\{0,1\}^{\ell_2(\lambda)} \mid... |
Suppose, we have a secure PRF $F$. Then can there be a MAC Scheme $I=(Sign, Verify)$ using F such that $I$ is insecure, but I is secure under the restriction that all the queries for MAC challenges are different?
|
I have read many cryptographic papers or articles where I have came across about the software and hardware implementation for the cryptographic algorithms. I want to know how its been done. Is there any need to create a separate software to do this. Why there is a need of using FPGA board for the hardware implementatio... |
I am using a Shamir Secret Sharing implementation in Java and I have the use case,
that I may have to generate more Subkeys of the Secret after I already generated some.
Generating them works, but if I combine the new keys with the old keys I can't recreate the secret.
I am using GF(256) as finite field.
For example:
... |
Any hyperelliptic curve having base field characteristic dividing group order?
A subgroup of order equal to the basefield characteristic, a large prime?
Having hard DLP in that subgroup?
Having pairing?
New elliptic-hyperelliptic cycle anyone?
SNARKs were introduced with QAP "intermediate" language to define com... |
How RSA keys are tested for primality if they are random generated? I imagine this could be time consuming task.
|
I'm looking for an authoritative reference about the history of salts in the context of hash functions. Why is the personalization string in a hash function called a "salt"? Who should be credited with introducing this technique?
So far I have found:
Plenty of speculative folk etymology on the Wikipedia discussion pag... |
As far as I know, the Second World War was won on codes that used obfuscation, not open source. These were also used during the cold war. For general use (not large companies with hundreds of employees who may or not be trustworthy) surely basic encryption that uses secret algorithms is still of use? I have asked this ... |
About the characterizations of Special Soundness, from Staking Sigmas we have that:
''A $\Sigma$-protocol $\Pi=(A,Z,\phi)$ is said to have ${\it special\ soundness}$ if there exists a PPT extractor $\mathcal{E}$, such that given any two transcripts $(x,a,c,z)$ and $(x,a,c',z')$, where $c\ne c'$ and $\phi(x,a,c,z)=\phi(... |
1- Why SHA2 has SHA224, SHA256, SHA384 and SHA512 variants?
2- Can we say SHA512 more secure than SHA256?
3- Symmetric ciphers use at most 2^256 security level and I saw on the internet people saying how impossible to reach that then Why SHA2 has a SHA 512 variant? Do we need 2^512 security level? İsn't it overkill?
4-... |
So Alice is sending a one-way message to Bob. Alice and Bob both, of course, have their own ECDH private keys, as well as each other's public keys.
I am using BouncyCastle 2.2.1 (BC) in this code. It appears (am I wrong?) that Alice and Bob must have the same Derivation and Encoding vectors (dV and eV) to encrypt a giv... |
Section 4.1 of the paper “Nonlinear Diffusion Layers” [Y. Liu, V. Rijmen, G. Leander] defines the nonlinear function $\rho$ over $\mathbb{F}_{2^m}$ as follows: $$\rho : \mathbb{F}_{2^m}^4 \to \mathbb{F}_{2^m}^4 : (x_3, x_2, x_1, x_0) \mapsto (y_3, y_2, y_1, y_0),$$ where $$y_i = x_i \oplus (x_{i + 1} \boxplus x_{i + 2}... |
I've recently implemented & hosted an Oblivious Pseudo-Random Function (OPRF) based on multiparty/oprf i.e. Burns et. al. EC-OPRF as an AWS Lambda function / API, that can be recurrently used providing an ID (or getting a random one assigned). Also did some web searches prior and after, but haven't ran across anything ... |
This was a CTF challenge I was unable to solve, but I thought I may had come close.
We were given two $N$'s $N_1$ and $N_2$ each calculated with $P_1 \times Q_1$ and $P_2 \times Q_2$; however, $P_1 = P_2 + 2$ where $P_2$ was still prime.
$Q_1, P_2, Q_2$ where calculated by what I think was a fairly standard method (usi... |
I'm working with the secp256k1 elliptic curve and have point doubling and point addition formulas for this curve.
If a point is given $Q_x$ and $Q_y$
Qx = 112711660439710606056748659173929673102114977341539408544630613555209775888121
Qy = 25583027980570883691656905877401976406448868254816295069919888960541586679410
pe... |
I was reading this article on Wikipedia, but I don't seem to understand how this holds: $u^\phi \equiv u^0 \mod n$. Can someone explain it to me? Thank you.
Key Generation
Given block size $r$, a public/private key pair is generated as follows:
Choose large primes $p$ and $q$ such that $r \vert (p-1)$,
$\operatorname... |
In 2012 CRIME attack effectively killed TLS compression. Has anything changed since 2012 regarding compression in TLS or have modern browsers sacrificed security over performance?
If browsers now use TLS compression how does it bypass CRIME/BREACH?
|
I came upon the following hash function (pseudo-code):
function customHash(integer:user_input)
{
user_input = user_input modulo 2654435789
user_input = user_input * 2654435789
ret_to_user = user_input >> 32
return ret_to_user
}
The goal of the problem I am trying to solve is:
Find two inputs [i,j] tha... |
I'm developping an Swift app that communicate with a Java legacy backend using AES GCM, my biggest problem is that Java let you use a 8 bytes iv/nonce (and the legacy code is written with 8 bytes nonce). You can't do that in swift, it result in error.
I can't find in javadoc what happen to nonce too short, i guess they... |
Given:
A function $$G: \{0,1\}^{3n} \to \{0,1\}^{6n}$$ which is known to be a secure Pseudorandom Generator (PRG).
A derived function $$G'(x_1 \| x_2) = G_b(x_1\|0^n\|x_2), \text{ where } x_1, x_2 \in \{0,1\}^n.$$
Question:
Can we assert that $G'$ is also a PRG?
Observations:
$G'$'s output maps to a specific subset... |
This is probably obvious, but I cannot find it anywhere, since all textbooks define OWFs for average-case hardness.
Do we known if worst-case one-way permutations exist assuming $\mathbf{P} \neq \mathbf{NP}$? I don't require average-case hardness, it suffices that the function is hard to invert in the worst-case. That ... |
In the paper located at https://eprint.iacr.org/2011/401.pdf, suppose we replace matrix multiplication with bitwise XOR operations in Definition 5.1 to create an LWE degree-k PRF. I'm seeking clarification regarding how this alteration affects the proof outlined in section 5.4, particularly with respect to Theorem 5.10... |
A Merkle Tree OTS scheme such as XMSS pregenerates 2^h keys that are tied to 1 public key
When the 2^h keys run out, does all the 2^h keys get removed/deleted and the device pregenerates another new 2^h keys and the corresponding public key?
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