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I'm working on a problem, where given 12 ciphertexts, I'm trying to decode the 12th and find out the key. I've implemented a crib dragging attack, where the crib is a purely guessed word (not known/given), I'm sturggling to actually build the key based on the output, as it seems to be all gibberish...
# ciphertexts we... |
refers to FIPS 186-5 document, I have a question about RSA Key generation A.1.6 method, "Generation of Probable Primes with Conditions Based on Auxiliary", my understanding is that, this method sets restriction on the size of Auxiliary prime only, so it is possible to generate P and Q with different bit size. Compared ... |
It seems that in most Attribute Based Encryption schemes, the keygen algorithm is probabilistic, which means that given the same public key, master secret key and attribute set (or access structure), it may output different secret keys.
Is my opinion correct? If correct, why is this? Will a deterministic keygen algorit... |
For starters, I don't need any don't-roll-your-crypto stuff. We're discussing a hypothetical.
So the idea is 3DES needs 3x the key size and achieves only 2x key size bit security. So using the 3x keyspace is essential for achieving the 2x bit security. Now entertain the same example, but this time it's 3AES-192. We hav... |
Paper: "Dispute-free Scalable Open Vote Network using zk-SNARKs" by Muhammad ElSheikh
Available at: https://arxiv.org/pdf/2203.03363.pdf
In this paper, the author has mentioned some pre-defined Groth16 zk-snark arithmetic circuits such as Mux(), LessThan(), GreaterThan(), etc. (page 5).
The author has also written thre... |
I have a 32-byte cryptographic key generated using .NET's cryptographic random number generator, and I'd like to use it as the key material to generate two other keys per user in my web application.
My plan is to use these two derived keys for AES-256-CBC encryption (the first derived key) and HMAC-SHA256 authenticatio... |
Hello my question is it practical to use HKD as a round function in a Feistel Cipher
I know you should not roll your own crypto, this is for learning purpose's only.
Take a look at my code and let me know what you think I'm not sure if I implemented the Cipher correctly this is my second attempt at cryptography my firs... |
I have been going through the lectures in ZKP MOOC here youtube series.
I am trying to understand the zk-STARKs discussed in video ZKP MOOC Lecture 8: FRI-based Polynomial Commitments and Fiat-Shamir.
In this video, the lecturer discusses zk-STARK protocol. The polynomial is chosen, a merkle tree is constructed over nt... |
I want to use AES-GCM-SIV for authenticated encryption of messages in my protocol.
Since it is a wireless protocol I want to transmit as few bytes as possible. For successful decryption I need to transmit the nonce alongside the ciphertext and the tag and in theory this nonce is 12 bytes for AES-GCM-SIV, but I don't th... |
The SBMC comic shared rules for a new version of tic-tac-toe today — I'm trying to figure out if there's a mental-poker/zero trustless version which could be played between two untrusting players (without the "monitor").
Is there a way we can know this is not possible?
Is there a way that this is possible?
The comple... |
In this CKKS bootstrapping paper https://eprint.iacr.org/2018/153 the authors use a Taylor expansion to approximate the complex exponential function within a small range. More precisely, for the input $t \in R_q$ the formula
$$
P_0(t)=\Delta \sum_{k=0}^{d_0} \frac{1}{k!} \left(\frac{2\pi \mathrm{i} t}{2^r q}\right)^k
$... |
Let $X \in \{0,1\}^{2n}$ be a uniformly distributed random string and $Y \in \{0,1\}^{2n}$ such that $H(Y) = n$.
Does this imply that $Pr(X=Y) = 2^{-n}$? If it's not, is this probability necessarily neglible in $n$?
I've only been able to show that $H(X|Y) \geq n$, but I'm not very sure what it implies about this proba... |
As defined in Kyber's specification 1, the NTT consists of two formulas:
$$\hat{f}_{2i} = \sum_{j=0}^{127} f_{2j} \zeta^{(2 \cdot \text{br}_7(i)+1)\cdot j}$$
$$\hat{f}_{2i+1} = \sum_{j=0}^{127} f_{2j+1} \zeta^{(2 \cdot \text{br}_7(i)+1)\cdot j}$$
Judging by the formulas, I would assume that the NTT is now implemented i... |
Are there any password-authenticated key exchange (PAKE) algorithms in FIPS standards?
|
In this paper, one of the facts stated was that $\text{IND-CPA} \not\implies \text{EKR}_p$, in which $\text{EKR}_p$ is defined as the property that for a polynomial number accessible of oracles p with p keys, an adversary is not able to determine any key and plaintext pairs within polynomial time. Here's how the paper ... |
I'm reading the article named "Characterizing the qIND-qCPA (in)security of the CBC, CFB, OFB and CTR modes of operation".
An attack on CTR mode is presented in the article. The proof of thm 1 states:
Adversary prepares the state $|+\rangle$ and makes a query to embedding oracle using it.
Adversary receives $\sum_{x}|... |
I tried to recover public key from P256 signature.
With 2 recovery id ( 0, 1 ), signature makes 2 public key.
And I tried to verify signature with public key and verification was succeed all of 2 keys.
Isn’t it correct that only one of the two should succeed?
Or is there some cryptographic knowledge I don't know about?... |
As we know in block ciphers, the distinguisher means that despite thousands ciphertexts (and plaintexts), allows an attacker to distinguish the encrypted data from random data. This attack is important because the secret key is ofen applied once related to many ciphertext.
My first question is what does it mean the dis... |
I'm seeking guidance on mitigating side-channel attacks in a cryptographic application where securely overwriting memory with zeros after use may not always be feasible. While I understand the importance of this practice in preventing memory disclosure vulnerabilities, I'm encountering situations where the secrets stor... |
I know that information can be changed by changing the frequency of electromagnetic vibrations.My question is, can I change the frequency according to my encryption algorithm? That way I can get a frequency that doesn't match anywhere. This would increase the reliability of my algorithm.
cable radiates. Can I algorithm... |
The section 3.1 of the GHS11 mentions that:
Given the $q_L$-ciphertext $c = (c_0, c_1)$ (that encrypts a polynomial $a \in F_2[X]/F(X)$), we postprocess it to get $c^\prime = (c_0 + c^*, c_1) \text{ mod } 2^{r + 1}$ as above, and then use the encryption of $s$ from the public key to compute the simple decryption formu... |
In my scenario we have the Issuer I, Verifier V and Prover P.
Now the prover send some messages to I and I signs these messages with I's private key.
These messages can be easily sent from P to V and be verified by V.
Now i want to bind these messages to a private key from P, so only P can use these messages. We could ... |
We are given a number of distinct RSA public keys $(e_i,N_i)$ sharing the same unknown decryption exponent $d$. The $e_i$ were computed from $d$ drawn first, so we have different public keys. Can we recover $d$ in any manner?
(Edit) We also know $d$ is 333-bit. $N$ is the product of $p$ and $q$ which both are 512-bit p... |
I have an MD5 hash and need to generate a file that matches it.
There are absolutely no constrains on the contents of said file, it can be binary gibberish.
The only important thing is that it matches the hash.
Is this possible?
I have the original file that produces the hash, but the new file is not allowed to be "vis... |
Consider RSA with $p$ and $q$ large distinct secret safe primes in interval $\bigl(2^{(n-1)/2},\,2^{n/2}\bigr)$, and private key $(N,e,d,p,q,d_p,d_q,q_\text{inv})$ computed as
$$\begin{align}
N&=p\;\!q\\
d_p&=3\\
d_q&=5\\
u&=p-1\\
v&=(q-1)/2\\
d&=u\;\!\left((d_q-d_p)\;\!(u^{-1}\bmod v)\bmod v\right)+d_p\\
e&=d^{-1}\bmo... |
I recently started learning zero-knowledge proofs. I found that in many zero-knowledge arguments, the verifier is required to randomly select a challenge $r\in\mathbb{Z}_q$ and send it to the prover. Afterwards, the prover calculates the form $x_1=x_0+rx$ and sends it back to the verifier.
I noticed that the length of ... |
Refer to an interesting article (link) on Medium on the subject matter.
To understand more about pRandomValue and vRandomValue.
The article mentioned, "pRandomValue, on the other hand, is used to hide (contents of purple box) from Veronica"
(1) But, Veronica already knows (contents of purple box), so why to hide?
(2) (... |
Why does TLS 1.3 (Client/Server) Hello require a random number? Wouldn't a sequence number also work?
I do understand that a sequence number is predictable but I don't see why this would be a problem in TLS 1.3.
|
I am confused about padding when using a Message Authentication Code (MAC). This paper suggests using a different key if the message is padded, and otherwise not, which really confused me. An example is the following construction (FCBC MAC):
I want to understand padding in detail, so I will make this question bigger. ... |
I am currently learning about the Dual_EC_DRBG protocol and I am stuck at the calculation of the initial state with the point P. For context, I am using the secp256k1 curve with a = 0 and b = 7. I have two points P and Q provided to me already. I am also using a nonce that will initialise the state.
From my understandi... |
I know how an Enigma works and that the reflector means a current flow must return by a different route but my question is this. After returning from the reflector and through the rotors, it passes through the plugboard before lighting up a different letter than was entered. Now imagine the ‘a’ key is pressed and retur... |
We know that, for one-way function $y=f(x)$, it's hard to compute $x=f^{-1}(y)$, but there exists an efficient algorithm $A(y,t)=f^{-1}(x)$ once we know the trapdoor information $t$.
I'm wondering, whether or not this property can be generalized to function of functions. i.e.
Is there a trapdoor one-way function $OWF(f... |
Let's have two integer-vectors $v_1$ and $v_2$ that are encrypted by McEliece public key. An intermediate node between the sender and receiver receives the two encrypted vectors $\text{E}(v_1)$ and $\text{E}(v_2)$ and it needs to add $v_1$ to $v_2$.
What will be the best choice in terms of computation cost, assuming th... |
The assignment I have is as follows:
Let $l=2^{128}$ and let $x$ be a random integer satisfying $0\le x \le l$
Let $\oplus $ be the XOR operator and $E_k$ an AES encryption with $key=k$
Let the signature of a string $M=m_{1}||m_{2}\dots||m_{n} $ where $||$ denotes concatenation of strings where $m_i $ is a binary strin... |
Oded Goldreich in his book [Foundations of Cryptography, 2004, Section 3.2.3] proves a theorem by polynomial number of hybrids.
In rather recent years, Marc Fischlin and Arno Mittelbach published a paper [FM21, IACR 2021/088] and prove lemma 3.1 (equivalent to Goldreich's above theorem) by first considering 4 types ... |
In my company we want to switch from PKCSv1.5 to PSS for RSA signing. This is because of the marvin attack vector.
My question is, if an adversary can see many similar messages that were signed with both schemes, does this have an adverse effect on security?
If so, are there known fixes that won't force a padding switc... |
Given the following two preconditions:
It is almost impossible to reconstruct a bitcoin private key if an attacker only has one half of the private key as well as the public key.
It is almost impossible to reconstruct a bitcoin private key if an attacker has an SHA512 hash of the private key as well as the public key.... |
I have an issue about AES whitebox protection as it is possible to decrypt data and get the whitebox encryption and decryption logic even without the ability to extract the original key. In my knowledge, until now there is no unbroken implementation of AES whitebox. My question is: is there any option to hide/obfuscate... |
I'm trying to understand if using non-injective encodings for Elliptic Curve ElGamal encryption is dangerous.
A standard probabilistic encoding defined by Koblitz for elliptic curves over $\mathbb{F}_p$ works roughly as follows (see this answer for details):
Fix some value $\ell < bitlength(p)$
Choose a random integer... |
For a (possibly complicated) function $f: X \rightarrow Y$, can we design a set of encryption scheme $Enc, Func\_Enc$ such that, for $\forall x \in X$,
$$Func\_Enc(f) = g \text{ where } g \text{ is another function} $$
$$ g(Enc(x)) = f(x) \quad \forall x \in X $$
Also, $g$ shouldn't leak information of $f$, and $g(Enc... |
I have been playing around with implementing a three-tier PKI recently. My PKI structure is as follows:
Root CA
Intermediate CA 1 (Name constraint: DNS .example.com, Email: .example.com, pathlen 1)
Intermediate CA 2 (Name constraint: DNS: .example.org, Email: .example.org, pathlen 1)
VPN Application CA (EKU Constrai... |
As far as I can tell we don't have any good key exchange post-quantum candidates. SIKE was broken some time ago.
It is possible to reach an authenticated shared secret by having the public key holder do PKE to send a secret to the private key holder and even have it reply with its own secret back in order to reach a un... |
I'd like to find a mechanism to evaluate the SHA-256 compression function using multi-party computation, but I'm not sure what's possible given the current state of the art and would appreciate some pointers in the right direction.
Specifically, I have set of parties (which must be scalable to more than two!) who each ... |
The elliptic.js library allows instantiating ECDSA with the edwards25519 curve.
I've rarely seen this combination in the wild. Is this fine? Are there any known bugs?
|
In an attempt to understand the mathematical operations related to encryption with elliptic curves, in particular finite field arithmetic (Modular reduction) I found in the Montgomery reduction that Montgomery form is an alternative finite field representation. what is this suppose to mean ? what it does differ from th... |
When the Electronic Frontier Foundation and distributed.net broke the DES Challenge III in less than a day, revealing the message See you in Rome (second AES Conference, March 22-23, 1999), what was the actual full value of the key they found?
I wasn't able to find it published anywhere online.
|
Quick disclaimer, I am pretty new to cryptography. I only understand the basics of asymmetric and symmetric encryption. In particular, RSA and AES.
I have a project where my service is receiving an encrypted SAML payload. As per the project description: a Public key 2048 was used to encrypt the payload and a Private ke... |
Shamir secret sharing1 is a common method to split an arbitrary secret (login credentials, symmetric or private key) between $n$ persons, so that a threshold of $k$ persons is required to rebuild the secret. The share given to each person is about the size of the original secret2.
The question asks how to make the shar... |
From Schneier's blog, which seems to have been written in response to a somewhat recent Quanta magazine article:
The winner of the Best Paper Award at CRYPTO this year (2023) was a significant improvement to lattice-based cryptanalysis.
So the result of the IACR eprint version of the referenced paper by Ryan and Heni... |
Simple question, but I couldn’t find an answer as I know about signing but don’t want it.
The aim would be to encrypt someone’s bet parameter as a short message using the private key and use the public key in order to verify/prove that the decrypted short cyphertext match the original parameters while making the cypher... |
I have a database table that needs to be shared between multiple parties. There is a sensitive column than must be obfuscated in a way that preserves equality relationships between records. A trusted party must have the ability to reverse the obfuscation. Is there a composition of cryptography primitives that satisfies... |
By the pigeonhole principle, we can demonstrate that arbitrary lengths of random data are uncompressible in the general case.
But let us imagine that I claim that I have created an oracle that can compress arbitrary random data by a certain ratio.
In such a case, I don't want to show you the internal details of my orac... |
is factoring RSA given 30% MSB of p and 30%MSB of q possible in polynomial time?
Notice that it is known that given 50% MSB of p or q it is doable in polynomial time using Coppersmith's theorem
|
I've been learning about aggregate signatures lately, are there any overviews or learning materials about aggregate signatures (including security properties)?
|
I'm trying to prove that an inefficient double-lengthening PRG exists, i.e. construct a PRG $G: \{0,1\}^n \rightarrow \{0,1\}^{2n}$
My current approach is to bound the number of poly-time non-uniform algorithms as the number of boolean circuits, which is $2^{n^2}$, then we can say there $2^{n^2}$ functions, we will cal... |
First of all apologies if this is not the right place. I am not very knowledgeable in cryptography but I thought you can at least point me in the right direction of research.
The following is a toy problem I tried to to analyse for fun and see if it's possible to find and answer.
It might be the case that the way I hav... |
We are given an El Gamal variant and are requested to find the decryption scheme and the security of the encryption. The variant operates on a group $\mathbb{G}$ of prime order q and g, h are two generators of the group $\mathbb{G}$ (the relation between g and h is unknown). The key generation and encryption are the fo... |
Of course this is a question with an answer that is due to evolve.
A 2002 paper about TWIRL stated that the cost would be around 10M\$ and an other 10M\$ to manufacture the device. A later 2007 paper claimed to have improved the design and created an actual FPGA, though at that time they were still used special bus rat... |
I'm trying to write a webserver.
I'm using TLS_ECDHE_ECDSA_WITH_AES_128_GCM_SHA256 (secp256r1).
I generated a CA certificate using OpenSSL (using prime256v1).
I generated the hash using server_random + client_random + curve_info + temp_publickey (just binary connect).
But when I test, OpenSSL returns them:
read from 0x... |
Let a plain text message M be DES encrypted with two different keys (K1 and K2) to produce the encrypted messages E1 and E2 (for K1 and K2 respectively).
Lets assume we setup a brute force attack which tests all possible keys K1 and K2 until the decrypted messages M1 and M2 are equal.
Is it mathematically possible to f... |
In standard Shamir's Secret Sharing schemes the shares are generated from randomly generated polynomials. I was wandering if it would be possible to create some predefined shares that a user would be able to use. e.g. in a threshold of 5, 2 shares are predefined by the user and the 3 others are generated like normal.
M... |
I am a self taught front-end developer and I am just trying to get my cryptography terminologies straight. I will make some statements. Can someone correct my mistakes?
Question 1
I read that cipher is an algorithm used for encrypting and decrypting data. Did I misunderstand?
Question 2
I found these regarding RSA:
C... |
For RSA or elliptic cryptography, can we use the same public/private keys for several exchanges, or is that unsafe? Does it lower the security of the protocol?
To me it doesn't matter, as receiving multiple encrypted messages does not give more information about the factorisation of the public key. Am I correct?
|
Would it be possible to use ChaCha20 as a block cipher? With the key, the entire block function can be reversed.
|
I'm working on a network where nodes communicate using AES-CCM encryption, within a context of tight bandwidth limitations, making every bit count. The setup uses a nonce that combines a 16-bit node address, a timestamp incremented every 100 seconds (with only the offset transmitted), and a 10-bit counter unique to eac... |
In FIPS 204 (https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.204.ipd.pdf): "The vector $\textbf{t}$ is compressed in the actual public key by dropping the $d$ least significant bits from each coefficient, thus producing the polynomial vector $\textbf{t}_1$. This compression is an optimization for performance, not secu... |
I am currently reading the paper Multiparty Unconditional Secure Protocols (https://dl.acm.org/doi/10.1145/62212.62214). They use blob for commitments. The purpose of blobs is to allow a participant $P_i$ to commit to a bit in such a
way that she cannot later change her mind about the bit, but nobody else can discover ... |
in reference here the FFT trick for $X^n+1$ is discussed with reference to the Number Theoretic transformation. On page 5, the Chinese Remainder Theorem is used to define the mapping.
So far so good. But I am particularly interested in how to arrive at the statement that on the k-th level we have the following relatio... |
I am curious about the structure of the quotient ring in Ring LWE. So $R=\mathbb Z_q[x]/(x^n+1)$, where q is prime, $x^n+1$ is an irreducible polynomial and $n$ is a power of 2. So, this structure would not be a ring anymore, it would be a field. So, why is it called ring and referred it as Ring LWE?
|
Here is Zipcrypto decryption algorithm:
Key(0) <- 305419896
Key(1) <- 591751049
Key(2) <- 878082192
update_keys(char):
Key(0) <- crc32(key(0),char)
Key(1) <- Key(1) + (Key(0) & 000000ffH)
Key(1) <- Key(1) * 134775813 + 1
Key(2) <- crc32(key(2),key(1) >> 24)
end update_keys
loop for i <- 0 to length(pa... |
I need a 128-bit hash function which is extremely fast since it will be used for generating unique IDs for billions of objects. It doesn't need to be a cryptographic hash function nor does it have to act as a PRF (though I would imagine any decent one would).
The only requirements are amazing collision resistance and s... |
I know that the OTP is considered to have perfect secrecy, but I haven't seen anything about its security against chosen ciphertext attacks, and I was wondering about its secrecy in this regard. My intuition is that it shouldn't be since I'd imagine it has the same issues as CTR$ against a chosen ciphertext attack, but... |
How to calculate Cardinality of an Elliptic curve over $\mathbb Z_{23}$.
$E: y^2 = x^3 + x + 1$ defined over $\mathbb Z_{23}$.
|
When it comes to applications, such as multiplication or addition, is there any difference between Shamir secret sharing and additive secret sharing?
|
I am having difficulties understanding a sponge construction, as I don't really understand whether the long internal state of a sponge construction is compressed in the squeeze phase, or whether bits are extracted from it.
So like I always do with things I don't understand: I coded a simple prototype.
So is this an exa... |
For an exercise at uni I am tasked with optimizing the execution speed a chaos based image encryption algorithm 1. While I have taken an introductory class to information security, I never came accross chaos based encryption before and have been unable to find any authoratative resource explaining its significance.
Can... |
We have values in the range $[a, b]$, and we apply a differential privacy mechanism to add noise to these values. After obtaining the noisy values, we employ the following truncation function: if a noisy value falls below $a$, it is truncated to $a$, and if the noisy value exceeds $b$, it is truncated to $b$. Does this... |
I have two secure pseudorandom generators, $G_1 : S\rightarrow R, G_2 : R\rightarrow T$. Now I need to prove that the PRG $G_3(s) = G_2(G_1(s))$ is secure.
I figured that I would construct two separate attack games, and assume the existence of an adversary $A$ that can distinguish the output of $G_3$ from a truly rando... |
I read in this answer here that if the ciphertext is reasonably larger than the key size, Vigenère cipher is easily breakable.
Is there a way to repeat the key if it is reasonably smaller that the ciphertext size and be immune to statistical information leak at the same same?
I have been thinking in XORing a keystream ... |
We have a set of query answers, i.e., $A = \{A_1, A_2, \dots, A_m\}$ and then we add noise to each of $A_i$ using a mechanism ($M$) providing differential privacy, i.e., $M(A_i) = O_i$. We denote the set of noisy query answers by $O = \{O_1, O_2, \dots, O_m\}$.
Let's say an adversary is given the sets $A$ and $O$ (in s... |
p256OrdMul method in crypto/internal/nistec/p256_asm_amd64.s,
// func p256OrdMul(res, in1, in2 *p256OrdElement)
TEXT ·p256OrdMul(SB),NOSPLIT,$0
MOVQ res+0(FP), res_ptr
MOVQ in1+8(FP), x_ptr
MOVQ in2+16(FP), y_ptr
// x * y[0]
MOVQ (8*0)(y_ptr), t0
MOVQ (8*0)(x_ptr), AX
MULQ t0
MOVQ AX, a... |
Performing a key exchange with post-quantum KEMs is very different to ECDH, which will likely cause vulnerabilities in protocols during the migration to post-quantum cryptography.
One example is that different KEMs can have different binding properties, leading to re-encapsulation attacks if you're not careful.
Some le... |
Is there an easy to understand and intuitive "one fits all" definition for the concept of diffusion that is applicable to both modern binary cryptosystems as well as classical ciphers?
For a bit of background:
I am currently in the process of writing some teaching materials for high school students (~16 year olds) abou... |
I'm trying to design an encryption and decryption device that is extremely secure, but simple in design so that it can be understood and audited.
Here is my attempt, do you see any vulnerabilities?
The device consists of a keyboard, 2 LCD character displays, a SD card reader, and 3 arduinos:
The SD card has no file s... |
Say I have three 64 byte values that I hash into three sha256 hashes (H1, H2, H3). The data does not contain any secrets and it all public data. I am instead hashing the data for integrity purposes.
Now lets say I do the following:
CombinedHashesValue = H1(as bigInt) + H2(as bigInt) + H3(as bigInt)
H4 = sha256(Combine... |
I'm studying Private Information Retrieval for my class. I couldn't find any good resources online apart from various papers written on it. Can somebody recommend a textbook, lecture or any other good resources for Private Information Retrieval?
|
I am reading about GKR protocol from Justin Thaler's book - Proofs, Arguments & Zero Knowledge
On Page 59,
In the first message, $P$ tells $V$ the (claimed) output(s) of the circuit. The protocol then works its way in iterations towards the input layer, with one iteration devoted to each layer.
I am a little confused... |
Does there exist a proof (paper reference welcome) that if a signature scheme is EUF-CMA, and the signatures are always encrypted, then the resulting signature scheme is SUF-CMA?
That is: let SIG be an EUF-CMA signature scheme. Then SIG' is defined as follows:
s = SIG(secret key, message)
c = ENC(K, s) where ENC is a ... |
I used an open-source programming language called Lucee / Cfscript that is closely related to Adobe Coldfusion. The default function that developers use to encrypt and decrypt data (usually for passwords or cookie contents etc) is meant to be compatible with a version of Coldfusion that released in 2002. Given that the... |
Imagine an Encryption Algorithm which applies a classic Shift Cipher (also called Caesar or ROT-X) to a text (with only lowercase [a-z] and the space ' ' character), but has one parameter r (randomness) to decide if in each round/iteration attempting to encrypt one char c, it encrypts the character c+key, or if it inse... |
I am designing a service where each user has both a unique 256-bit private and public ID. These IDs should be derivable from one another, but only within the backend of my service (as to not expose the private IDs to other users). For this purpose, I am considering using AES with a key known only by my service, but thi... |
I was reviewing past exam questions and came across this one:
Is it secure for A (the garbler) to allow B (the evaluator) to
run a garbled circuit twice with different inputs? They
aim to compute the output of a function F for two pairs of inputs,
A encrypts the circuit and sends the garbled
circuit to B. B also recei... |
I'm studying for an exam and came across this question:
When an electronic signature of a message claimed to be produced by
Alice is verified we typically verify (at least the first time):
that the public key belongs to Alice by verifying that it has been signed (along with additional information) by a certificate au... |
I know Signal uses public/private key E2E encryption to ensure it's impossible for them to read the contents of messages. WhatsApp does too, hence Signal's main attraction is that it additionally claims to avoid collecting metadata pertaining to the messages (unlike WhatsApp). Their server code, last time I checked, ... |
I have two statements which I think are correct:
$\beta, s$ are unknown.
Only $g^\beta$ is known to the prover but not any of $g^{\beta s^i}$ for $i \ge 1$.
If the prover is able to find group elements $A$ and $B$ such that $e(A, g^\beta) = e(B, g)$ then the prover knows a field element $a$ such that $A = g^a$
And a ... |
Does anybody have a library of fastest parity finding algorithms in RNS representation? By parity I mean $x \bmod 2$ where $x$ is the number between $0$ and $N=\Pi m_i$ and all moduli are odd.
I have found a fast algorithm, but since it is quite simple, I need to check whether it pre-exists or not. I found a reference ... |
Given that an algorithmic implementation of a linear feedback shift register based encryption scheme is (much?) more secure against side channel attacks; why are hardware platforms usually used?
I get that speed is a factor in stream/block cipher systems used in communication protocols ie. error correction or encryptio... |
This is related to Is it possible to create a mix of predefined and generated shares for Shamir's Secret Sharing?, but I have unfortunately lost access to that question and can't merge accounts right now.
I now know that it is most definitely possible to create some predefined shares but was looking for further informa... |
Why was the simulator/extractor specifically given the power to rewind "time" instead of a different super power?
Was it defined in the first ZKP paper that the simulator and extractor would have this power as a "standard" and then everyone went with it or was there more thought put into it when giving it this super po... |
Consider a standard supervised machine learning problem on private data. Instead of using DPSGD, suppose that one uses a non-private SGD scheme to produce optimal model parameters $\theta$ (done in the private data enclave, as with DPSGD), and releases publicly $\theta + \eta$, with $\eta \sim$ Laplace$(0, \varepsilon)... |
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