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How to determine the prefix of a SECP256K1 compressed public key

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 ...
Sinodevi's user avatar
-5 votes
0 answers
9 views

What is new math worth?

Methods of finding factors of numbers, not requiring regular factorization https://www.ebay.com/itm/186093464767 https://www.ebay.com/itm/186093499754 https://www.ebay.com/itm/186093531060
Trevoryoung343's user avatar
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0 answers
6 views

How to add Crypto++ library to NS3 using waf build system? [migrated]

1.I already downloaded the crypto++ 8.8.0 source code & moved them to a folder called cryptopp. 2.Furthermore, I have also created a wscript file in the cryptopp folder. 3.Now how should I proceed ...
Aditya's user avatar
  • 1
0 votes
1 answer
74 views

48-bit nonce reuse with ChaCha20

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 ...
Florebol's user avatar
0 votes
1 answer
45 views

Is there any cheaper way for multiplying a plaintext scalar to a vector?

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(\...
Zhengyi Li's user avatar
0 votes
1 answer
56 views

Group secret agreement for clients do not have connection to each other

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 ...
Anh Nguyễn Tuấn's user avatar
2 votes
2 answers
105 views

Textbook RSA using multiple low public exponent e

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 ...
LilLee's user avatar
  • 31
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0 answers
58 views

Client authentication: only talk to trusted clients?

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? ...
ddyer's user avatar
  • 499
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2 answers
138 views

PAGE 2: Can I move elements from cyclic subgroup to its cyclic parent group?

We will continue our previous topic here⬇️ for clarity... 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/...
Josh666's user avatar
  • 11
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0 answers
32 views

Transmit a password to inheritors

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 ...
mifrey's user avatar
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1 vote
1 answer
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Could Yao's Millionaires' problem be used as a problem of binary search?

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 ...
bd55's user avatar
  • 23
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0 answers
67 views

RSA encryption two characters at a time

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 ...
Stefan Shkenderov's user avatar
1 vote
1 answer
53 views

Convert multiplication in $GF(2^{128})$ to bitwise AND?

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 ...
Halulu's user avatar
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0 answers
46 views

Kyber and Dilithium usage limits?

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.?
Joe's user avatar
  • 73
1 vote
0 answers
76 views

Zero Knowledge Proof for SHA-256 preimages

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,...
Bernardo Rodrigues's user avatar
-1 votes
1 answer
47 views

Padding oracle attack when padding is on prefix

Is there any attack on padding Oracle AES-CBC encryption when padding is added as a prefix instead of suffix or is it secure completely
John_cena's user avatar
2 votes
1 answer
61 views

Computing the intersection of two lattices

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 $...
Sam Jaques's user avatar
  • 1,065
-1 votes
0 answers
56 views

Ethereum Money Loss: Seeking Help to Identify the Hacker [closed]

I hope this post finds you well, but I'm currently facing a significant problem that I need your help with. My phone was inexplicably hacked, leading to the loss of a substantial amount of money from ...
Amine's user avatar
  • 1
1 vote
1 answer
153 views

Can I move elements from cyclic subgroup to its cyclic parent group?

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 &...
Josh666's user avatar
  • 11
0 votes
0 answers
26 views

Decryption only on a specified future date?

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 ...
Harvs's user avatar
  • 101
2 votes
2 answers
149 views

A question about "attacks on MAC key space"

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)...
hellobc's user avatar
  • 21
1 vote
2 answers
58 views

Zero Knowledge Argument for Elliptic Curve Multiplication/Inverse Multiplication Correctness?

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 ...
Justice Almanzar's user avatar
0 votes
1 answer
40 views

Can we have an asymmetric key in AES? Clarification about PBKDF2 and AES-GCM in WebCrypto

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 ...
borracciaBlu's user avatar
0 votes
0 answers
31 views

Java AES T-Tables Implementation

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 ...
schegga_BC's user avatar
1 vote
2 answers
72 views

Efficiently detect that a ciphertext is meant for Alice

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. ...
Guiomar Raissa's user avatar
0 votes
1 answer
52 views

Shamir Secret Sharing for API Authentication

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 ...
Michael's user avatar
1 vote
0 answers
44 views

Trouble interpreting CTR_DRBG test vector results

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). ...
MDude's user avatar
  • 11
-1 votes
0 answers
77 views

Could we build PSPACE-based cryptography - more secure post-quantum? [closed]

It seems not safe to exclude possibility of e.g. some next generation quantum computers being able to attack NP problems (e.g. 2WQC) - so maybe it is worth to start thinking of shifting the ...
Jarek Duda's user avatar
0 votes
0 answers
21 views

Nature of differentially private Laplace mechanisms

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}_{...
meeeeee's user avatar
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0 answers
28 views

Crack simple prng based stream cipher [closed]

I wrote a simple PRNG based stream cipher: ...
pacman's user avatar
  • 207
1 vote
1 answer
34 views

Regarding the Digital Signature Algorithm During Client Authentication in TLS 1.2

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 ...
dusk's user avatar
  • 11
1 vote
0 answers
71 views

Is it better to use PBKDF2 with SHA-512 and 1e6 iterations or SHA-256 and 6e6 iterations?

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 ...
icl7126's user avatar
  • 111
0 votes
2 answers
84 views

Encrypt with private key decrypt with public key

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 ...
user23952's user avatar
  • 101
1 vote
0 answers
26 views

Function Secret Sharing

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 ...
asml's user avatar
  • 11
0 votes
0 answers
21 views

Discrete Gaussian distribution on a lattice vs. the periodic Gaussian function on a lattice

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 ...
user1035648's user avatar
2 votes
1 answer
67 views

Would encrypting several layers of a filesystem be a waste?

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 ...
Xcrowzz's user avatar
  • 21
3 votes
0 answers
95 views

Who originally generated the elliptic curve now known as P256/secp256r1

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 (...
poncho's user avatar
  • 143k
0 votes
0 answers
80 views

How to "break" this PRF scheme?

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 ...
HughJass24's user avatar
4 votes
0 answers
69 views

Masking countermeasures for AES-GCM

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 $C$...
yoyo's user avatar
  • 327
0 votes
0 answers
18 views

Question on Aleo zkVM

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 ...
Walker's user avatar
  • 61
1 vote
3 answers
55 views

Zero-Knowledge Proof of Encryption with a Specific Key

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 ...
Jordan's user avatar
  • 111
2 votes
3 answers
450 views

Check if encrypted text is equal without decrypting or doing heavy calculation - AES

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? I wanted to create only field ...
FSDev's user avatar
  • 23
0 votes
0 answers
28 views

How IV value shapes the State Matrix of PHOTON AEAD?

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 ...
Mohammadsadeq Borjiyan's user avatar
1 vote
0 answers
42 views

Is the SNI extension signed in TLS 1.3?

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 ...
warren's user avatar
  • 33
0 votes
0 answers
25 views

Interacting with Zksync sometimes returns an "invalid value for value.blockHash" error

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 ...
Javier Cabrera's user avatar
2 votes
1 answer
130 views

Does using a block cipher in CBC mode *twice* result in an all-or-nothing transform (AONT)?

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. ...
Arnold Snooli's user avatar
0 votes
0 answers
61 views

HMAC-SHA256 key length against key recovery attack

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-...
dragonfire2000's user avatar
0 votes
0 answers
47 views

Sagemath help: Introduction to Lattices

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 ...
mandoo's user avatar
  • 1
0 votes
0 answers
36 views

2 XORed AES-ECB ciphertexts, zero key and piece of plaintext

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 ...
stefan09's user avatar
0 votes
0 answers
11 views

what is (n, n’, δ, u) generalized BBS assumption?

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.
Fangfang Sun's user avatar

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