All Questions

Filter by
Sorted by
Tagged with
0 votes
0 answers
5 views

When incrementing a private key by 1, by how much is the public key Incremented?

Simple question but I’m unable to find the answer again. If you have a secp256k1 keypair and you increment the private key by 1, then a faster way to compute the new public key is to perform an ...
user2284570's user avatar
0 votes
0 answers
10 views

What is the meaning of asymptotic security proofs in practice?

In Katz & Lindell's Introduction to modern cryptography (3d edition) we have the following statements in chapter 3: A scheme is secure if for every probabilistic polynomial-time adversary $A$ ...
Mr. B's user avatar
  • 69
0 votes
0 answers
19 views

Quantum many time pad

In the Quantum One Time Pad (https://homepages.cwi.nl/~schaffne/yfke/QOTP.html) an n-qubit quantum state can be perfectly encrypted (as in the classical OTP) using 2n classical bits. In the classical ...
manta's user avatar
  • 23
0 votes
0 answers
24 views

Keccak implementation confusion

I am implementing a Keccak core in VHDL and I am currently almost done yet I am still facing some problems and would appreciate your insight. First of all I wanna ask about the padding, I know that we ...
pro orp's user avatar
0 votes
0 answers
33 views

New Service to Service Protocol Presented for Public Scrutiny (Time-based Token Signing), Is it Safe?

I came up with the following protocol to provide a life-time for JWT tokens while differentiating services to communicate securely with web services (service-to-service) using symmetric key signing ...
Adam Memisyazici's user avatar
1 vote
1 answer
64 views

GKR Protocol - does it matter which gate in each layer the SumCheck Protocol is run on?

I am reading about GKR protocol from Justin Thaler's book - Proofs, Arguments & Zero Knowledge Page 61, Lemma 4.7 $W_i(z) = \sum_{b,c \in \lbrace 0,1 \rbrace^{k_{i+1}}} add_i (z,b,c)\cdot (W_{i+1}(...
user93353's user avatar
  • 2,211
0 votes
0 answers
18 views

Enigma machine Rejewski cataluge and ring settings

I'm trying to simulate Rejewski cyclometer and developed a code that run over all ~100k posibilities and generates for each setting an id that looks like that: 1313_111212_11221010 I run my code with ...
user116068's user avatar
0 votes
0 answers
29 views

Inquiry about the Suitability of Lyapunov Exponents for Image Cryptography [closed]

I am currently exploring different encryption methods for securing digital images, and I've come across the concept of using Lyapunov exponents for encryption and decryption. However, I'm unsure about ...
zeraoulia rafik's user avatar
0 votes
0 answers
47 views

Why is perfect secrecy defined under a ciphertext-only threat model?

I recently acquired Katz & Lindell's Introduction to modern cryptography (3d edition). Currently I'm on page 27 where we have the following definition: Definition 2.3: An encryption scheme (Gen, ...
Mr. B's user avatar
  • 69
0 votes
1 answer
92 views

How do I generate a sequence of numbers with unpredictable differences

This question relates to bit flip attacks on OTP encrypted messages. Lets say I've got a list of numbers from 0 to 2^24-1 I want to re-order the list so it has the following property: If you start at ...
Drew's user avatar
  • 127
0 votes
0 answers
30 views

Don Reble's eliptic curve semiprime [closed]

In 2005, Don Reble managed to make a 1084 digit semiprime using the elliptic curve method. This semiprime is the following number N: ...
Nilo Berardi Casas's user avatar
0 votes
0 answers
26 views

Large semiprime factorization [closed]

Through a code or algorithm, give the two prime factors of the following number: ...
Nilo Berardi Casas's user avatar
0 votes
0 answers
24 views

Padding oracle attack with known padding length

I have a question regarding the padding oracle attack. When I search the Internet the attack it seems that everyone has the same way of performing it. We learned another way in class and I try to ...
katibthemathematician's user avatar
1 vote
2 answers
36 views

Is this procedural code correct description of `g is a primitive root module of p`?

I am a web developer with only high school level knowledge of math. I wanted to understand how TLS 1.3 is better than TLS 1.2. Along the way, I bumped into the concept of Diffie Hellman Key Exchange ...
learningtech's user avatar
1 vote
0 answers
52 views

Do one-way functions imply target collision resistance?

I'm reading the paper: One-Way Functions are Necessary and Sufficient for Secure Signatures, by John Rompel, which gives answer to the question in the title; but I'm confused about these sketched ...
Zijun Zhuang's user avatar
1 vote
1 answer
65 views

Is it possible to use Diffie-Hellman protocol for symmetric group?

I was asked this question during one of my first cryptography classes, and I'm not sure if I understand it correctly. To begin, I know that after using the Diffie-Hellman protocol (which itself is ...
karolajoj_PL's user avatar
1 vote
0 answers
30 views

Should not we eliminate $\pm 1$ from $\mathbb{Z}^\times_N$ in RSA accumulators?

RSA accumulator is an authenticated set built from cryptographic assumptions in hidden-order groups such as $\mathbb{Z}^\times_N$. Any set $S=\{e_1,e_2,\ldots,e_n\}$ can be commited via a commitment $...
Somudro Gupto's user avatar
1 vote
0 answers
24 views

Need help with Cryptohack's ProSign 3 ECDSA problem

I'm trying to solve the CTF challenge called ProSign 3 at Cryptohack platform which involves exploiting an ECDSA signing service that allows us to sign a fixed message being padded with the time ... ...
YazeedAllabadi24's user avatar
0 votes
1 answer
33 views

How can LCG based stream ciphers be broken?

I'm watching Christoph Paar's Introduction to Cryptography lecture series on youtube. In it he describes an example of an insecure stream cipher which uses XOR as the encryption and decryption ...
Nick's user avatar
  • 101
1 vote
1 answer
63 views

Why is zero knowledge defined via simulation w.r.t. inputs *in* the language?

In every definition of zero-knowledge (ZK) proof systems that I have seen (see, e.g., this one on Wikipedia, or this primer by Goldreich), a proof system $\langle p, v \rangle$ for a language $L$ is ...
Lewis Hammond's user avatar
2 votes
1 answer
49 views

Proving DES complementation property: y = DES(k,x) ⟹ /y = DES(/k, /x)

Below is my proof for this. I was not sure if this is correct and was also a little confused regarding the complementarity property of DES. Does this property mean there is a serious vulnerability in ...
sangaCat's user avatar
0 votes
0 answers
27 views

I want to find the Zero Value Points on SECP256R1 curve... Is there an alternative to Chien's method of finding roots over large Finite Fields?

This PDF explains that on certain elliptic curves, there exists ZVP (Zero Value Points) that cause zero value registers during the scalar-to-point multiplication (i.e during the double operation or ...
Cyth's user avatar
  • 1
1 vote
0 answers
51 views

Zero knowledge proof of a linear expression in the exponent [closed]

Alice sends to Bob a value $B$ in $\mathbb{G}$ a group of high order. There are distinct elements $h_1$ and $h_2$ of high order of $\mathbb{G}$, and Alice wants to prove to Bob that she knows some ...
Adam54's user avatar
  • 261
0 votes
0 answers
32 views

Reaching the bound of Boneh and Durfee Attack

According to the paper, theoretically,we can get $\delta=0.292 \lt 1-\frac{1}{\sqrt{2}}$,but how to set the lattice and implement it in sagemath? I generated some data by ...
Cred Mao's user avatar
0 votes
0 answers
34 views

Proving Insecure Hash Function Through Not Collision Resistant

There is a function H : {0, 1}* → {0, 1}^n. On input a message m and two shares of it x, w such that m = x ⊕ w, the function outputs y = H(m) = H(x) ⊕ H(w). How would I find that this NOT a collision ...
sangaCat's user avatar
0 votes
0 answers
53 views

Difficulty of factoring large semiprime N if given a second value y = (p-1)*r, where r is a random large prime?

Lets say we have 2 public values: N and y $$ N = pq $$ $$ y = r(p-1) $$ Where p, q, and r are large primes, are different, have a large distance between them and are kept secret. I have three ...
block103's user avatar
0 votes
0 answers
29 views

Key recovery attack on BIP32-Ed25519

BIP32 describes a method for deriving secp256k1 key-pairs. BIP32-Ed25519 is a similar method for Ed25519. For both, the derivations proceed from a root key-pair by adding a random-like integer to the ...
Permutahedron's user avatar
0 votes
1 answer
86 views
+100

Row level database encryption scheme

I am developing a row level database encryption scheme. Ideally I would not do this and instead rely on something vetted, but I haven't been able to find such a scheme online. My primary concerns are: ...
Daniel's user avatar
  • 1
1 vote
0 answers
22 views

Proof of UOWHF construction from a strongly universal hash family

I am currently trying to rigorously prove Lemma 2.2 of [NY]. More specifically, a UOWHF family can be constructed from a composition of a strongly universal family $G_k = \{g : \{0, 1\}^k \rightarrow \...
Pontakorn Prasertsuk's user avatar
2 votes
2 answers
116 views

Key Exhaustion Risks in Symmetric and Asymmetric Cryptography

For the symetric keys it is recommend that the same key should not be used to encrypt large number(2^32) of cipher blocks to avoid the key-exhaustion risk. Curious to know whether the asymmetric key ...
Bhuvan's user avatar
  • 123
0 votes
0 answers
30 views

1-0 padding, padded messages of some other message m′according to this padding scheme? [closed]

1-0 padding. Are all messages m of length divisible by n, the block length, padded messages of some other message m′according to this padding scheme?
youbin kim's user avatar
2 votes
0 answers
40 views

How does the Functionality know whether a sender/receiver is malicious?

I am new to the field of MPC and I'm trying to learn VOLE. I can understand the maths in functionality and protocols but can't get a sense of the security implications behind them. For instance, I was ...
John's user avatar
  • 21
0 votes
0 answers
34 views

How to attack the shuffling of correlated numbers?

Suppose I have a function that accepts vector input $x$ and outputs vector $y=f(x)$. I want to protect the output $y$ through shuffling numbers in it. I hope the shuffling can confuse the attacker by ...
Zhengyi Li's user avatar
0 votes
0 answers
24 views

How to implement a SKE scheme supporting single-message multi-ciphertext using LowMC and GMW?

I currently have a LowMC scheme and a GMW scheme. How can I implement a symmetric encryption scheme that supports single-message multi-ciphertext? In simple terms, I want to implement a protocol like ...
song's user avatar
  • 11
0 votes
0 answers
181 views

Is the cryptography scheme over lattice still secure? [duplicate]

In https://eprint.iacr.org/2024/555, the author proposed a quantum algorithm to solve LWE problem. How serious is its impact on the existing scheme over lattice.
guangyu liao's user avatar
0 votes
0 answers
15 views

Reduction For MAC systems

I am not too knowledgeable regarding reductions for message authentication code encryption. Here is an example I found: There is a MAC' based on a preliminary existing MAC as such: MAC'(k, m) = MAC(k,...
sangaCat's user avatar
0 votes
0 answers
25 views

User-friendly tutorial In JohnTheRipper (JtR) for beginners? [closed]

I have been struggling to understand the format in JtR. I am a pentesting student and trying to do a customized wordlist rule. How do you dictate the order of the password. like how do you tell the ...
TorJaks669's user avatar
44 votes
2 answers
6k views

Polynomial-time Quantum Algorithms for Lattice Problems

A new paper, by Yilei Chen, whose title is Quantum Algorithms for Lattice Problems (https://eprint.iacr.org/2024/555) appeared on eprint and it claims to solve hard lattice problems, such as the ...
Hilder Vitor Lima Pereira's user avatar
1 vote
0 answers
76 views
+150

Security of $E(c,k) = AES(c,(k \oplus c)\cdot (2^{n} - 1 - c)) $ used multiple times with low bit keys $k$. Avoids MitmA?

More precisely the Encryption function will be $E(c_i,k_i,i)$ with a 128-bit cipher/number $c_i$, a 16-bit encryption key $k_i$ and a 8-bit index $i$ as input using a Xor key obfuscation $k'$ with ...
J. Doe's user avatar
  • 433
0 votes
1 answer
58 views

wrting algorithm for torsion group elements

Yesterday,I took an exam. There are two questions I received very low points. I will write the first question in this post. The question says let $E:y^2:x^3+kx+1$ in GF(p) be an elliptic curve where p ...
user avatar
1 vote
1 answer
43 views

Can two different AES keys have the KCV by chance?

I am trying to check KCVs of a few keys. I am generating the KCV for the keys using the method mentioned here https://crypto.stackexchange.com/a/11873/115990 Question: Can KCVs of two different AES ...
humbleCoder's user avatar
0 votes
1 answer
60 views

Lightweight length preserving encryption

I'm in need of an encryption algorithm that can be easily implemented in c, doesn't drastically increase the size of the encrypted data (the data to be encrypted will be approximately 200 bytes and ...
Hristos's user avatar
1 vote
1 answer
72 views

In x25519kyber768 what is the use of the server kyber keys if only the client public kyber key is used for encapsulation in kem?

In x25519kyber768 what is the use of the server kyber keys if only the client public kyber key is used for encapsulation of the kyber shared secret in kem?
Shekhar Sivaraman's user avatar
-2 votes
0 answers
37 views

GCD EGCD Problem [closed]

Im doing a Cryptography CTF and the chall has this code ...
LM.'s user avatar
  • 1
1 vote
0 answers
38 views

Is it possible to compute the X25519 scalar multiplication of the SSH key exchange using the ED25519 sliding window implementation?

There are many different ED25519/Curve25519/X25519 implementations around. I focus on two of them: https://github.com/jedisct1/libsodium https://github.com/floodyberry/ed25519-donna The libsodium ...
bebbo's user avatar
  • 156
-3 votes
0 answers
41 views

school's exam, Is anyone know the two answer? [closed]

Here is a school's exam, Is anyone know the two answers ?. Thanks a lot !
user109471's user avatar
1 vote
1 answer
107 views

What is the purpose of making salted passwords public?

So I was reading through an article about how passwords are salted and hashed through a cryptographic function here, and found out that hashed passwords, along with the plaintext salt values are ...
mantot123's user avatar
0 votes
2 answers
57 views

How does MixColumn collapse 4 active S-boxes into 1?

In AES Proposal: Rijndael, page 34, there is the following figure with MixColumn transformation pattern for two columns: I'm trying to reproduce these paterns. The pattern in the column marked in ...
Alexey Kalmykov's user avatar
1 vote
1 answer
63 views

Is it possible to homomorphically evaluate an encryption circuit?

I know that it is possible to homomorphically evaluate a decryption circuit as it is the main idea behind bootstrapping, but I was wondering if it was possible to evaluate an encryption circuit ...
ProfCornDog's user avatar
0 votes
1 answer
39 views

Vulnerabilities of a word-level substitution cipher

What kind of attacks would be possible against this kind of substitution cipher? Every word in the plaintext is to be replaced with a random string of the same length The encryption of any given word ...
u2892's user avatar
  • 1

15 30 50 per page
1
2 3 4 5
609