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I am implementing BLS signature verification on smart contracts and I have a question regarding the way that Ethereum verifies the signature. Recall that bls signature works as
$e(P_2,H(m)_1)_T=e(G_2, S_1)_T$ where $_2$ and $_1$ denote points of $G_2$ and $G_1$, and $_T$ for $G_T$.
Off-chain, you take your secret $x$ ... |
Is it possible to get the x, y of the compressed public key?
I have decompress it and naturally it gives the xy of the decompress public key.
I need the xy coordinates of my compressed public key . How do I get it? Is there a python script I can get my hands on?
Update: I have tried it via
#! /usr/bin/env python3
im... |
Assume a standard ECC curve in a prime field $\mathbb F_p$ with $p\equiv3\pmod 4$, such as secp256k1; and code turning a bytestring for a compressed ECC public key into an Elliptic Curve point, that does as specified except in the following two emphasized spots:
2.1. Parse $M=Y\mathbin\|X$ as a single octet $Y$ follow... |
Here's a modification of the textbook RSA scheme, in an attempt to achieve semantic security.
Key generation: chooses public key $pk = (N,e)$ and secret key $sk = d$ as in any RSA-based encryption scheme.
Encrypting message $m \in \mathbb{Z}^*_N$ using $pk$: Choose $x\gets \mathbb{Z}^*_N$, output $\mathsf{ct}_1 = x^e ... |
Hi I'm trying to understand the logic behind a CTF challenge basically we are given a program which encrypt some data, we have the following options:
Select encryption mode (EBC, CBC, CTR, OFB, CFB)
Encrypt the flag and see the resulting ciphertext
Encrypt a choosen plaintext and see the resulting ciphertext
Now I th... |
I'm curious to hear of algorithms that use this new standard (there is a new IRTF CFRG Draft for it, for instance). It's useful for verifiably deterministic signatures on elliptic curves, but what else?
|
I am wondering does AES-GCM which uses Authenticated Encryption provide us with all 3 properties (Authenticity, Confidentiality, and Integrity), or does it not provide integrity?
|
Suppose the highest level is $L$. There are 2 ciphertexts from 2 different messages under the same secret key but in different level, one is in level $\ell$: $\mathsf{ct}(\pmb{m})\in\mathcal{R}_{Q_{\ell}}^{2}$, one is in level $k$: $\mathsf{ct'}(\pmb{m}')\in\mathcal{R}_{Q_{k}}^{2}$, and $k<l-1$.
We want to calculate ho... |
I want to encrypt a private key $sk$ (it's actually an RSA private key in PKCS#8 format) with another person's (and/or my) public key $pk_A$ for secure storage. With JWE, it is possible to use hybrid encryption: we generate a random symmetric key $k$ to encrypt $sk$ and then encrypt $k$ with $pk_A$.
I would use AESGCM+... |
A lot of writeups, books & webpages say that to get 112 bit security (i.e $2^{112}$ steps), you need to use RSA or DH with 2048 key size or ECDH with 224 key size. In reality, I think what is meant in most of these cases is modulus size or group size rather than key size, but for some reason it's always referred to as ... |
I noticed that when using AES-256-CBC with a 128-bit IV, the ciphertext is always at least 16 bytes long (size of IV).
I also noticed that when using AES-256-GCM with a 96-bit IV, the ciphertext size can be smaller than the IV.
Normal? Why?
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I'm working in a context where it is cheaper to calculate pow(a,b) via modular exponentiation (modexp(a,b,m)) than to do exponentiation directly. For this I need the minimum modulus value such that the function returns only the exponentiation part of the function call.
Is there an efficient algorithm that exists to cal... |
I was wondering out of the functions (MD5, SHA-1, SHA-256, and SHA-512), do all provide 128-bit pre-image resistance and 128-bit second-image resistance?
Also, out of these hash functions, do only SHA-256 and SHA-512 provide 128-bit collision resistance? (Due to $l/2$ bits of security)
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Let we have $G_1 \times G_2 \to G_t$
let $g_1 \gets G_1, \\g_{2.1} \gets G_2, \\g_{2.2} \gets G_2$
$$e(g_1^a,g_{2.1}^b) = e(g_1, g_{2.1})^{ab}$$
$$e(g_1^a,g_{2.2}^b) = e(g_1, g_{2.2})^{ab}$$
Is it working?
|
I have two linkable ring signatures, each signed with the same key pair. Therefore, the signer's public key will appear in each of the rings. However, the set of other public keys appearing in each ring are different.
Is it possible to tell that the same person signed both rings, or can this only be known if each ring ... |
Imagine a scenario whereby Alice and Bob have a symmetrical messaging system for talking with each other. It's effectively two polystyrene cups joined by a piece of string. Crucially, there is no central server, and nobody logs into nothing. They do though both have the same messaging application. Also imagine that the... |
I'm wondered about what arithmetic operations are supported from FHE.
I want to know for 2nd Gen(BGV,BFV), 3rd GEN(GSW,CGGI), 4th GEN(CKKS)!
Is 3rd can support more than and/or/not? I heard it is for a bit.
Thanks
|
In modern cryptography, IND-CPA is the lowest security we want. We want at least IND-CCAx security from encryption mode. Their relation can be found in
2007 Authenticated Encryption: Relations among notions
and analysis of the generic composition paradigm, Mihir Bellare & Chanathip Namprempre
All classical block ciph... |
I have two private-key encryption ($Π$ and $Θ$) and their concatenation $Π\#Θ$. For example:
$$
Enc_{Π\#Θ}( \ ⟨k_Π, k_Θ⟩, \ ⟨m_Π, m_Θ⟩ \ ) = ⟨ \ Enc_Π(k_Π, m_Π),\ Enc_Θ(k_Θ, m_Θ) \ ⟩;
$$
(Same for Gen and Dec)
I need to prove that if $Π\#Θ$ is secure against passive adversaries, then both $Π$ and $Θ$ are.
Actually I... |
ECDSA works by computing the hash of a message and then computing the signature for it. ECDSA uses the signature:
$$s = k^{-1}(h + rp_{pr})\,\textrm{mod } n,$$
where $n$ is the order of the group, $k$ is a randomly sampled nonce, $r$ is the projection onto the $x$ axis of $kg$, where $g$ is a group generator.
If you ar... |
The Argon2 specs claim that Argon2 can be used both for password hashing and key derivation.
I want to generate from a single password both a hash for authentication and a secret key to use for encryption. (It would be nice if this could be generalized to any (reasonable) number of hashes and keys.)
From the specs, it... |
I'm a bit confused regarding the bilinear pairing operation. Let's say I have a Public key of a receiver $P_r = P^x$ and I want to create a symmetric key using KEM with a pairing operation. If I chose $R = rP$ and compute $V = (Pr, P)^r $which results into $V = (P^x, P)^r = (P^x, rP) = (P^x, R)$. Here, I am confused ab... |
I was taking a look at the PRESENT lightweight cipher presented here. You can see an implementation of it in Python here. It is basically a Substitution-Permutation (SP) cipher with ultra-lightweight encryption and lightweight decryption.
The algorithm for encryption is the following :
generateRoundKeys()
for i = 1 to ... |
I have short (8-byte) messages which are effectively true random numbers, and I want to encrypt these messages with a (pre-shared) key....
I'm using AES-CTR for this purpose -- but with the SAME IV each time (which is seemingly contrary to best practice).... but since EVERY message that I'll encrypt with this key is un... |
I'm new to cryptography and having a hard time understanding PRGs and PRFs.
Question: $G'(x)$ and $G''(x)$ are two different secure pseudorandom generators, and $G(x)=G'(x) \mathbin\Vert G''(x)$.
Is $G(x)$ still a secure
I thought $G(x)$ is secure at first, since $G'(x)$ and $G''(x)$ are secure, their outputs are unifo... |
Basically, I need to find the probability that DES(p, k1) = DES(p, k2) = c
My guess is that probability = 1 / 2^64 since that's the total number of possible outputs, but honestly I have no clue about crypto. Thanks in advance for any help!
|
The $(t,n)$ Shamir’s polynomial based secret sharing scheme is $(+,+)$-homomorphic in which the addition of two polynomials secrets equals the Lagrange’s interpolation of the sum-of-shares for the same subset of shares.
My question is: Does the two polynomials need to have the same degree to satisfy the SSS $(+,+)$-hom... |
Context
I am trying to build a simple protocol for key derivation. I want to use SHA-3 family hash functions, which (as far as I understand) should not be combined with HMAC because their security properties make HMAC redundant. Thus, HKDF — which uses HMAC — would also be unsuitable for key derivation using SHA-3 fami... |
I'm trying to understand the security proof of Shamir's Secret Sharing method, as I want to adapt the polynomial creation a bit, and I've found the proofs I had available to be surprisingly vague or holey.
Some nomenclature
Given a secret $S$ in the finite field $\mathbb{F}_p$ for a $(k,n)$ threshold scheme the Shamir'... |
Despite working with AES-GCM and other AEAD algos for a few years, I've struggled with the concept of 'authenticated' in the term 'AEAD'. In my own experience (of Unix, PKI and blockchain) authentication means being able to attribute actions towards a particular entity (eg, a user account). In the simplest case, say au... |
I am familiar with any algorithm that is based on the number of bits in a key (n-bit) and how to restore a key, such as the Discrete Logarithm Problem or Factorization.
When I use any algorithm for encrypting and decrypting images, such as RSA, how can I estimate this algorithm's security and work efficiently with ima... |
For example, if you have say, 3 distinct paragraphs of clear text a, b, c and you only know hash(a), hash(b) and hash(c), and then you have a clear text d, which claims to be the concatenation of a, b, and c, is there any way to use hash(a, b, c) to demonstrate that d either is or isn't a+b+c?
Not beng a math person, I... |
In Privacy-preserving machine learning, GC is usually used for privacy operation such as ReLU(x) where sign(x) needs to know. However, binary secret sharing also supports such computation via comparators($[x]_{encryted}$ > 0)(this paper).
While compare the performance, binary secret sharing is usually way faster than g... |
Suppose I have a set $S$ containing $n$ bit strings, where $n$ is on the order of about 10. Consider
$$\mathfrak{S} = \{ R : R \subseteq S, |R| \geq 2 \},$$
the collection of subsets of $S$ with two or more elements.
Does there exist a hashing function which outputs the same hash for any member of $\mathfrak{S}$?
A po... |
For communication between the client and the website, use password (P) as the key using AES-128. If P is less than 128 bits, it is padded with 0 to create a 128 bits key. is there any problem with such an approach if the average password length is 6?
|
Assuming evaluation in the online phase (no beaver triple/offline method used), each AND gate in GMW must be evaluated using a 1-out-of-4 OT. I've seen some sources (here, and here) say this can be implemented using 3 1-out-of-2 OTs over 1 bit strings. Can it also be implemented from 2 1-out-of-2 OTs over 1 bit strings... |
Is it feasible to efficiently calculate a homomorphic absolute value function over ciphertext given a pair of numbers $a$ and $b$, i.e., |a-b|? Although there are approximate methods that use addition and multiplication, their runtime in my project is intolerable. Is there any homomorphic absolute value function that i... |
I am using micro-services to interact between various cryptographic technologies like HSMs, keystores, vaults, etc., that are written in different languages. Usually, each technology, or even vendor, is using different names of the cryptographic algorithms, and in some cases they are also case-sensitive.
For example, J... |
$x$ is challenging string, $y$ is proof string. $\operatorname{H}$ is the proof-of-work (pow) function, to find a $y$ such that $H(x,y)<2^{256}/D$
$x ,y = \{ 0, 1 \}^{512}$
$\operatorname{H}(x,y) = \operatorname{SHA-256}(x \oplus y)$
find a $y$ such that $\operatorname{H}(x,y)<2^{256}/D$
the question is to prove:
If ... |
I totally have no idea about this Rabin decrypt problem.
source code:
https://github.com/shanzhuer/myctf/blob/main/crypto/rabin.py
Inside there were $2^{21}$ times of encryption and decryption of Rabin-cryptosystem, with 126 bytes plaintext, 1024-bit public key $N$(unknown 512-bit $p$ and $q$ when $p*q=N$)
the output l... |
I am trying to write a function that, given an EIP712 ECDSA signature, verifies the signature was signed by a particular person, and then (somehow) retrieves the information that is encoded in the signature.
Is it even possible to retrieve the unhashed data from an EIP712 ECDSA signature, or is it only possible to veri... |
this is my first post so I apologise if the formatting of my post isn't perfect.
I should start off by saying that this post is not for any malicious intent, rather for curiosity and understanding AES encryption/decryption.
I have been doing research about AES encryption and everywhere says that ECB mode should never b... |
It is known that there are two popular applications of lattices: dense sphere packings and lattice-based cryptography. I didn't find any information on the Internet about possible interaction of these domains. Let's forget for the moment that most dense lattices are quite theoretic constructions, hence they don't have ... |
Given p = 7 and q = 13, one can obtain n = 91, d = 29, e = 5. However, for plaintext with values less than the modulus both the public and private keys (n, d) and (n, e) are reversible, i.e. encrypting a plaintext value with either key and then using the same key a second time returns the original value.
What is the re... |
This is a slight variation of the shared nonce problem. We do have a lot more shared information between two nonces.
Given a random $k$:
$$
k_1 = ka,
k_2 = kb
$$
I am now signing two messages, which gives me $s_1,r_1,s_2,r_2$
Based on my understanding of the base equation for signatures in ECDSA
(with given generator $... |
I don't understand which DES key is used in the next round of Feistel construction.
As you can see below, we use our original key that has been inserted in permuted choice 1, where we got 56 bits, divided into two halves, $C_{i-1}$ and $D_{i-1}$. We will apply the left shift rule on that key and therefore obtain 16 dif... |
I understand that $\text{gcd}(m,n)$ needs to be $1$ so we can apply the Euler's theorem, and if it's not $1$, the result is one of the prime factors of $n$. But Why the result it is always $p$ or $q$? Couldn't it be any other number?
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I understand that if the $\gcd(x, n)\neq=1$ then the $\gcd$ is one of the $n$ prime factors, $q$ or $q$. But how is the fact that $x \not\in Z^*_n$ related to $\gcd(x, n)\neq 1$?
|
Does anybody know or can point me to a source about SHA2 vs SHA3 usage statistics.
SHA3 is newer and is claimed to be more secure but ... is it more widely used in real life deployments?
|
I'm trying to understand how lattice-based schemes with the Reed-Solomon proximity testing work and why the scheme in Bootle's et. al. Fig 3 has no aborts at all (nor big number of repetitions).
TLDR: How do PCPs and Reed-Solomon allow to avoid aborts and multiple repeats in Bootle's et. al. exact proof? I see no abor... |
In NTRUEncrypt, we choose polynomials $\mathbf f,\mathbf g$ (with suitably small coefficients) such that $\mathbf f$ admits inverses $\mathbf f_p, \mathbf f_q$ with respect to the moduli $p,q$. The relationship between the public $\mathbf h=\mathbf f_q\mathbf g\text{ mod q}$ and the private key $(\mathbf f, \mathbf f_p... |
Suppose I had a new public-key or key exchange protocol. How do I objectively evaluate it so as to determine if it is worth sharing with the broader community? Whenever developing a cryptosystem, it is important to ask "who cares?", to see if it addresses any challenges that current systems face, but it is unclear ex... |
One party (master) wants to send data to another party (slave) over an insecure channel using public-key encryption and signature schemes such that:
master is authenticated,
data is confidential,
data cannot be replayed.
The minimal assumptions are:
master has slave's public encryption key,
slave has master's public... |
When using BLS, let's say Alice signs each of the 5 messages ($m_1, m_2, m_3, m_4, m_5$), aggregates the signatures and sends the aggregated signature to Bob. Bob can verify it.
Here's the goal:
However, Bob would also like to send the aggregated signature by Alice to Charlie but hide the values of $m_2$ and $m_4$ mess... |
I'm working on a Chinese Remainder Theorem Garner's Formula problem in my Cryptography module and was hoping for some help.
Question:
Given the data below use Garner’s formula to find T,U and s
$$ N = pq = 6815731 $$
$$ s \% p = 1 $$
$$ s \% q = 62537 $$
$ s = a \% p $
$ s = b \% q $
$ T = p-1 mod q $
$ U = (b-a)T mod... |
When a tag8 compressed data packet does not contain compressed data i've seen some products simply handle the packet as a tag11 literal data packet, yet i find nothing in the 4880 spec old/new suggesting this is an acceptable behavior. what am i missing here?
|
What the state of the art for producing quickly verifiable proofs of correct computation when your proof is allowed to leak knowledge?
For context, I am inspired by Miden VM's promises:
For any program executed on Miden VM, a STARK-based proof of execution is automatically generated. This proof can then be used by any... |
The sever holds the N encrypted elements, each element is associated with an index (unencrypted). The receiver wants to retrieve only k-out-N elements using k-out-N OT.
The motivation for using OT is to retrieve only k elements, not all N elements, retrieving N elements results in storage overhead on the device (receiv... |
While I was reading the documentation for the cryptocode $\LaTeX$ package I stumbled across the "primitive" called puncturing in subsection 2.12. This was the first time I read about this "primitive". Additionally, I am no native speaker, which is why I have no intuition about what it could mean. Can someone explain it... |
I am confused about stream ciphers a little so I just wanted to clarify. We have a key that's lets say 2 bits. I have a message that's 8 bits. I used a pseudorandom generator that would add 6 bits to my key. Those 6 bits are deterministic and public. Hence why it's called pseudorandom, it looks random but because the 6... |
Im looking to learn about forging CBC-Macs.
Given the CBC-Mac for a Message M and the Key used to encrypt the message K.
Can I create a new message M' which would have the same CBC-MAC?
Original Unknown Message: M
CBC-Mac of Original Unknown Message: X
Key used in CBC Block cipher: K
New message with CBC-Mac = X: M'
|
I am reading a networking book by Mike Meyers, and it says that a certificate is a file that contains
A public key, and
A signature (cryptographic hash of the public key, encrypted with the private key).
I can understand that the signature helps ensure that the public key was not tampered with. If I make a request to... |
I'm somewhat new to cryptography and I've been looking at knowledge extractors in proofs of knowledge and I am a little confused by the use of somewhat different definitions.
In textbooks or early papers, (as an example see Definition 4.7.2 in Goldreich's textbook [G]), I've seen the knowledge property defined roughly ... |
I am trying to determine how to apply ZK proofs to the asymmetric scenario below.
Say there is a list of 5000 secret elements on a centralized web server.
Users are trying to guess what those 5000 elements are.
However, users don't want to reveal their incorrect guesses to the central server.
Users submits proofs of t... |
Does anyone know where to find bigram frequencies for English alphaber with space?
|
Suppose I first define some function f(x) where x is some unsigned 256-bit integer, and the function's output is a set of distinct strings of any length so that output set would be 2^256 unique strings, i.e. a bijection for the specified domain of x.
Example f(x) = 0xAA || x || 0xBB (|| indicates byte concatenation), b... |
I am trying to learn about basic hashing using the modulo operator and am a bit confused. In the text that I am reading, it says that the modulo operator can be used to accept an input of any length and return a fixed-size output. However, take 1mod11 = 1 and 21mod11 = 10. The first equation yields a one-digit number a... |
I have read that perdersen commitment can be used to hide the messages such as transactions by participants. The verifier will just have to make sure that the difference of the commitments is zero. But I don’t quite understand how is this verification valid.
For eg, for the input messages, 10, 5, 2, Alice could choose ... |
I am learning to utilize flush+reload method to get private key of CRT-RSA.
CRT-RSA calculates two parts separately: mp = c^dp mod p and mq = c^dq mod q
x = b^e mod m is calculated by the code below.
[![enter image description here][1]][1]
There is a loophole in this method, that is, the execution of Square-Reduce-Mul... |
Moderator note: this question has moved there at reverseengineering-SE.
I'm trying to reverse the save game of an old game. It use text codes to save the games (anyone remember this?). When decoded the data contains game info like level, checkpoint, objects in inventory, etc.
I ported the code of the decoding function... |
In the "On the Non-malleability of the Fiat-Shamir Transform" article by Faust et.al., there is a definition for unbounded NIZK. What unbounded means in this context? It does not look like perfect ZK because the distinguisher is PPT and not unbounded as required here.
|
In Whatsapp, are the same private keys used in all my devices? Is the sharing of the keys from scanning the QR code on the web browser to link to my device? Thank you!
|
Suppose in a network, the identity of users is their public key, which is generated based on the ECDSA algorithm. That is, to create a valid identity, a user must generate an ECDSA public key and then send it to the network administrator for validation. Then, the network administrator needs to know if the user followed... |
Assuming that I want to encrypt a 1 GB file with e.g. AES in GCM mode or ChaCha20Poly1305.
[I'm specifically referring to the cryptography module for Python: https://cryptography.io/en/latest/hazmat/primitives/aead/ but I can't find anything in the documentation]
For "non-AEAD" ciphers, the syntax is basically
cipher =... |
this is a school challenge.
I have a cipher file which is the audio file, and no key of course, encrypted with AES ECB mode. The size is around 550 Kb. I know the key size used is 16 bytes, and I have the plain file of 20 Kb that is part of the whole original plain file, but I do know the offset of it.
I guess attackin... |
I want to share the secret key of the BFV scheme among N users using the additive secret-sharing protocol (n-out-of-n threshold secret-sharing). Can anyone please help me to adapt the two algorithms correctly?
Note that the secret key of BFV is generated as a random ternary polynomial from
R
2
(
R
2
is the key d... |
Not sure if this falls into crypto from contextual point of view but it is about hashing algorithms. I have two directories -- assets/ and cache/. Anytime there is a file added, deleted, or changed in the assets/ directory, a corresponding, application specific file will be generated in the cache/ directory. On top of ... |
I know exactly how a generated BitLocker recovery key works and I can write a code to brute-force it.
How is the recovery key generated though?
I could think of some answers:
it is generated using an algorithm which generates a random number using a specific seed;
it is generated using some information extracted from... |
I've recently become quite interested in lattice based cryptosystems, and I wish to understand them more deeply. I have only a rudimentary understanding of the shortest vector problem (SVP), and its brother the closest vector problem (CVP), which are central to this form of cryptography, though I understand lattices, v... |
I want to implement Camenisch-Lysyanskaya Signatures based on the strong RSA (SRSA) assumption using python. However, I have a question.
Here public key of the signature PK=(n,a,b,c) and private key SK=p
But while signing the message, only the parameters from public key is used. Am I missing something because for signi... |
In Regev's Paper "On Lattices, Learning with Errors, Random Linear Codes, and Cryptography" he considers in the introduction of the paper the "learning from parity with error". Where we have an unknown $s \in \mathbb{Z}_2^n$ our goal is to find this $s$, given a list of equations with errors e.g. $\langle s,a_i \rangle... |
What kind of attack of image encryption that exist out there, especially if the cipherimage was created using secure stream-cipher like Salsa20 (256 key) or ChaCha20 (256 key)?
From https://cr.yp.to/streamciphers/attacks.html#chacha20 page, i know that the algorithm itself can be attack using Brute force attack to find... |
I am implementing pollard kangaroo to compute the discrete logarithm of a group element $G$ of generator $g$. $G$ is a$\mod p$ multiplicative group ($p$ a prime number). So, I want to solve $g^a=h$ knowing $a\in[[0,w]]$.
What I am basically doing:
Define $w=2^{58}$
I define $k$.
Split $G$ into $k$ subset $S_i$.
I defi... |
I am looking at the description of Weil MOV Attack from the Vanstone, Menezes Book (Guide to Elliptic Curve Cryptograpy)
Suppose now that the prime order $n$ of $P \in E(F_q)$ satisfies
$gcd(n,q) = 1$. Let $k$ be the smallest positive integer such that
$q^k \equiv 1 \pmod n$, the integer $k$ is the multiplicative orde... |
Let's say you downloaded a file from a certain website, and later the website claims that it didn't made that file available, is there any way to prove that the website is lying?
Example 1: You download a youtube video and the channel later delete the video and claim that the video was never there.
Example 2: A website... |
I saw some recent papers(e.g Encrypted DNS --> Privacy? A Traffic Analysis Perspective) about adopting ML technology to overcome cryptography implemented to ensure network security. Network packets have a fixed form and limited possibilities for each section which could be used as side-channels. I'm wondering what are ... |
CMAC is defined for AES for authentication. My question is pretty simple: is it possible to extend CMAC for ChaCha? Does it even make sense? I cannot find anything related and I am wondering if I am missing something trivial.
When compared to AES, there are algorithms for AEAD with AES, in addition to CMAC for AES. CMA... |
In the TLS 1.2 handshake, after checking the certificate, the public key from the certificate was used to encrypt the data to create a symmetric encryption key, hence the authentication took place on the factor of knowing the private key, as it is needed to decrypt that data.
In TLS 1.3, the public key cannot be used t... |
I need to send sensitive information from frontend to backend and from backend to frontend. Which is best to do this by encrypting all the communication between the parts? Should I use symmetric/asymmetric in encryption? What is the best approach?
|
I want to share the secret key of the BFV scheme among N users using the additive secret-sharing protocol (n-out-of-n threshold secret-sharing). Can anyone please help me to adapt the two algorithms correctly?
Note that the secret key of BFV is generated as a random ternary polynomial from R 2 ( R 2 is the key distribu... |
The famous names of mathematicians at Bletchley Park are now a matter of public record and include eminent figures such as Max Newman, JWS Cassels, Philip Hall and Sandy Green as well as the more cryptanalytically celebrated Alan Turing, Jack Good and Bill Tutte.
Other countries also began making use of mathematicians ... |
I'm doing a small code that performs a simple SSL/TLS analysis and I'm stuck on determining the size of the key exchange in the case of DH / DHE.
If I take the following example (wireshark capture) :
p Length: 128
p: acb31[...]
g Length: 1
g: 02
Pubkey Length: 128
Pubkey: 1935[...]
I just thought I could get the neces... |
The NIST publication for AES defines $Nb$ as:
Number of columns (32-bit words) comprising the State. For this
standard, Nb = 4.
In Section 5.2: Key Expansion, $Nb$ has been used to calculate the number of round keys to be generated.
Section 6.3 states:
This standard explicitly defines the allowed values for the key ... |
I need a way to make the signatures shorter, currently with a ring size of 1000 members I get a signature size of 34000 bytes, this is too big for me I need a way to make it smaller.
I tried compressing the signature with gzip but it only makes it bigger, the only other solution I can think of is to use other linkable ... |
I've been messing around with lattice based cryptography and came across the SWIFFT algorithm, a provably secure cryptographic hash function which has a security proof stating that finding collisions is as hard as reducing a lattice, a provably difficult problem, infeasibly difficult.
I could understand basically using... |
I am having difficulty visualizing the stepping process.
The permutation of Wheel I of Enigma I is as follows:
ABCDEFGHIJKLMNOPQRSTUVWXYZ
EKMFLGDQVZNTOWYHXUSPAIBRCJ
For this rotor, the stepping notch is at Y. The literature states that the letter Q is visible when the notch is positioned, and after the step, R is... |
I'm trying to verify a time stamp token embedded into a PDF using the PDF 2.0 feature of the "Document Time-stamp Dictionary". The embedded time stamp token is exactly the token of a time stamp response from a time stamp authority server.
Since the OpenSSL library of Ruby doesn't seem to provide the necessary interface... |
Imagine an MPC protocol where both multiplications and additions come for free (2 round). The protocol works over arithmetic circuits, and the security setup is as relaxed as possible:
Semi-Honest.
Honest Majorities.
Does such a protocol exist?
If so, what would be the most restrictive security model, and maintain t... |
I am wondering if there might be a scheme for the following scenario: Let's suppose a government wants a truly democratic intelligence agency. For this the government publishes all intelligence reports in an encrypted format to the public and allows people to do a majority vote to declassify its contents.
A naive solut... |
I have a pair of coordinates of which all values belong to $Z_{p}$ where $p$ is a prime. I want to construct a straight line that goes through those two coordinates. Then I want to generate two more random points on that line. I also need a function that returns the value of y given any x on that line. For that I can t... |
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