All Questions

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

Multi-recipient key exchange

The question is: does this public key encryption system have (roughly) the same security for n=1 as for say n=100? (and check my work that for n=1 it has exactly the same security as standard IES). ...
0
votes
1answer
58 views

To what extent would Bitcoin be private without address reuse?

Let's say Bitcoin had these rules from the start: An address with balance cannot more receive money An address must use all its money in one transaction This would prevent address re-use. To what ...
1
vote
0answers
35 views

All Curve25519 Parameters with Explanation

I'm trying to sum up all Curve25519 parameter and specification reasons. Can you tell me if I missed some important reasons or parameters in the following list?: Curve: Montgomery Curve. Reason: The ...
0
votes
0answers
18 views

Provable Data Possession

While Provable Data Possession seems to be a very useful and interesting tool for ensuring integrity of data outsourced into Cloud providers, I have never seen a reputed Cloud provider talk about this ...
0
votes
2answers
46 views

Find IV and the key ? AES with CFB or OFB

I have a question about the AES-128 and AES-256 encryption method. I need to encrypt 64-bit size data in and out. I want to encrypt them with AES. So I turned to AES-OFB or AES-CFB because these ...
0
votes
0answers
35 views

Small (code-size) hash functions

I am trying to implement a small encryption tool in as little code as possible as a learning exercise, and currently have managed to get everything to depend only on a HMAC construct. However, most ...
3
votes
1answer
114 views

Likelihood of signature collision with EdDSA

Taking EdDSA as an example, given the length of a signature is 512-bits for a given data payload, what is the probability of a collision where there is another 512-bit value that is also a valid ...
1
vote
0answers
37 views

Content Key Encryption for Multi-User data access

I recently worked out a concept for a use-case, but I'm not sure if my approach is good enough. So I would appreciate feedback and things to look out for, as I'm fairly new to this field. A User can ...
-2
votes
0answers
64 views

Deterministic DSA by Thomas Pornin (Java Illustration, its Errors) [closed]

(DISCLAIMER: I'm clearly seeking a point to be illustrated from a white paper as explained here, "How should questions be handled involving code?", and <...
0
votes
1answer
21 views

Why blinding integer $r$ needs to be co-prime with $N$ in blind RSA signature

According to blind RSA signature wiki the random value $r$ in $m^\prime=mr^e \bmod N$ needs to be relatively prime to $N$. Why is this a requirement? A follow up a related question: after $s$ (...
0
votes
0answers
14 views

Is there any digital communication medium that provided close-to-perfect security? [migrated]

Problem When I browse this forum, I constantly read about the weaknesses of popular "secure" messaging applications such as Signal, Telegram, and WhatsApp. Some of the most notable critiques ...
3
votes
2answers
101 views

What does perfect mean within perfect forward secrecy and why do some cryptographers disagree with the term?

In this blog post, Matthew Green says Forward secrecy (usually misnamed “perfect forward secrecy”)... The Wikipedia article on forward secrecy (which the same sentence links to in the blog) says ...
0
votes
0answers
30 views

I have a puzzle I can’t solve, need help [closed]

The only clue I have is that the person who wrote this writes their letters like numbers The message: 182119154193 x 151815209815414 0457185519125 The key, I ...
0
votes
0answers
49 views

Which cryptographic attacks can AES 128-bit withstand?

Most of the articles and forums are stating that the Brute Force attack can test the strength of an encryption algorithm. However, I am looking for those attacks that AES can withstand for the testing ...
0
votes
0answers
21 views

How to convert a 4 digit number (supposedly the PGP private key) into a PEM format and how to code this? [closed]

Someone sent me a PGP encrypted message (it's not a file but in a text message) and the private key to decrypt it is not given. But he gave me a hint, that the private key is a 4 digit number. I can ...
2
votes
0answers
33 views

Key strength comparison: symmetric key vs RSA/DH key

I came across different reputable sources quoting different equivalent symmetric key strengths for RSA/DH keys. This NIST paper (page 67/161) states the following offer corresponding security ...
1
vote
0answers
85 views

Generating a XOR Hash function for a given group of numbers to maximise collisions

Given $x$, a vector of $m$ distinct bit vectors of bit length $N$, I want to use an XOR-hash $h$ such that all $x_i$ collide to the same value. I define an XOR hash $h$ which takes bit vector $q$ as ...
0
votes
0answers
18 views

volume only saves files in clusters of 512 bytes, regardless of how large i select the cluster and format [closed]

I am experimenting clusters and formatting in veracrypt, and I have found that no matter how large or small I format the clusters in my veracrypt volumes, no matter how small the files I save, they ...
0
votes
0answers
49 views

Performing EdDSA/Ed448 employing Montgomery ladder

EdDSA can be efficiently performed employing the Montgomery ladder. In order to implement this method, the base point should be converted to Mont. space, then the Mont. ladder should be executed, and ...
0
votes
0answers
34 views

RSA encryption/decryption values not working as expected [duplicate]

I'm faced with an issue I can't seem to understand when it comes to RSA. Below are my values for all of the parameters, unfortunately I can't seem to get the expected decrypted values from my ...
1
vote
0answers
47 views

Retrieve message from rsa ciphertext based on some conditions

Let's say: $x = m^{e-1}\bmod n$ $y = m^{d-1}\bmod n$ Here $m$ is a message, $e$ is public exponent, $d$ is private key and $n$ is the modulus. Now if I know $e, x, y$, and $n$, can I retrieve the ...
1
vote
0answers
20 views

What guarantees that a mined block will be accepted on the network? (Blockchain)

What ensures that a mined block will be accepted on the network? I mean, if I mine a valid block in the blockchain, and I transmit it to the network, what is the incentive to people accept it? Doesn't ...
2
votes
0answers
44 views

Is it okay to have no IV when using AES-CBC with unique keys, that are however derived from one shared key?

Given $\operatorname{AES-CBC}$ (128-bit), with $IV=0$ and unique encryption keys $$K_{Enc} = \operatorname{CMAC}(MK, \text{known_text})$$ where $MK$ is a shared symmetric 128-bit key and $\text{...
1
vote
1answer
34 views

Which are the current solutions to the illegal values in the homomorphic secret sharing?

There is a usual example about homomorphic secret sharing, focused on e-voting. Supposing we use Shamir's scheme for the Secret Sharing system, a participant generates a polynomial whose a0 is +1 (yes)...
1
vote
0answers
21 views

Generating a recovery phrase for a RSA key-pair

What is an optimal way to associate a RSA key-pair with a recovery phrase/seed for access recovery purposes? I've seen a lot of cryptocurrency wallets provide this feature, however, I'm not looking to ...
2
votes
1answer
111 views

Is choosing $1$ as a public exponent valid in RSA?

I know it will not encrypt anything. But is $1$ valid as a public exponent in an RSA public key?
0
votes
0answers
23 views

Tools for testing TLS throughput [closed]

I want to knwo if there are any open-source tools for testing the throughput of TLS protocol implements such as OpenSSL?Intern command line in OpenSSL is ok if there is one.
0
votes
1answer
27 views

How to solve high exponent attack for same message in RSA

I know Håstad's broadcast attack when e = 3, but what if e = getPrime(randint(350))?
8
votes
0answers
61 views

Is anyone using ORAM in practice?

Oblivious RAM has been around in theory for about 30 years at this point. Is anyone using it in practice? Has it made its way into industry? (Including any variants such as MPC ORAM or ORAM that uses ...
0
votes
0answers
46 views

ROLLO : security bits parameters

In ROLLO -Rank-Ouroboros, LAKE & LOCKER p.20, it says that "Notice that for 128 security bits parameters, the practical security is rather higher than 128 at about 170 bits." How Can I ...
0
votes
0answers
32 views

Need to encrypt files after a certain lead time elapses [closed]

I edit books created in MS Word. Sometimes the authors do not want to pay for my services in a timely manner. How can I return the books to the authors un-encrypted, then encrypt the file two weeks ...
1
vote
2answers
75 views

RCON for AES 192 and 256

This is question about how many RCON values are used in AES 192 and 256. I read the NIST Publication introducing AES and in Appendix A.2 and A.3 (Key Expansion for 192 and 256-bit keys), only $rcon_1$ ...
1
vote
1answer
41 views

Is possible that find numbers where the product of 3 numbers is congruent modulo to 1?

It is possible that find the $a, b, c$ randomly in here? $$ abc \equiv 1{\pmod {\varphi (N)}} $$ Instead of $$ de \equiv 1{\pmod {\varphi (N)}} $$ in the RSA Algorithm.
-2
votes
0answers
15 views

Setup Geth Node for the first Time. HELP Please! [closed]

Hello my Name is Sven and i am from Germany.I need Guidance from someone with advanced knowledge in ethereum. I created December 2017 an ethereum Wallet. On March 2018 i invested in P3D. I forgot this ...
1
vote
2answers
63 views

Is 50% of bits changed in every round always gives 50% of changed bits in the end?

Let's say we have a cipher with such property, that every round change 50% of bits in every block in average. Is it obvious or it means that after few rounds we will get exactly 50% changed bits? If I ...
0
votes
0answers
29 views

How Should Form Input be Encrypted for sending to a Server?

I apologise if this question is a duplicate. I couldn't find any similar questions. I am writing a web app that consists of a series of drop-down style question menus. These generate more drop-downs ...
2
votes
3answers
133 views

Diffie-Hellman key exchange, then so what?

I know how the Diffie-Hellman Key Exchange (DHKE) works. But where is it used? And ok, now both have the same key. But how are those keys used anyway? I've heard that HTTPS is using the DHKE. Ok, but ...
0
votes
0answers
14 views

Need help deciphering [closed]

So i recently was added on an arg type game from a friend and there is a bit of code that im not entirely sure what the cipher is, so i was wondering if anyone could help me on figuring it out. "...
0
votes
1answer
32 views

Curve25519 base point speed up

In the paper regarding Curve25519 DJB defines the base point to be $P_{base} = (9,y)$. The main reason for choosing it this way is, that $P_{base}$ has a big prime order which gives security ...
3
votes
1answer
45 views

Are skeleton keys possible for ECCDSA?

As alluded to here (split-key vanity addresses for bitcoin), ECCDSA-keys can be merged such that the sum of two private keys $S=S_1+S_2$ yields a public key which is the sum of the respective public ...
0
votes
0answers
21 views

Authenticating and encrypting data for an automated system

I wish to distribute a file from A to an automated system B. The requirements are: Contents are encrypted Contents are tamper proof Contents origin is verified To do this I have devised the ...
2
votes
1answer
39 views

Is there a way to prove knowledge of a limited resource like a phone number just to the people who already know about it?

For instance, let's say Bob's phone number is X and Alice has somehow identified that Bob's phone number is X. Now she doesn't have a direct way to contact Bob, so she wants to post in a public forum ...
0
votes
1answer
99 views

Why discrete logarithm modulo composite moduli not popular and not defined in standards?

The classical discrete logarithm problem is to find $x$ such that $g^x\equiv h\bmod p$ where $p$ is a prime and $g$ is generator of multiplicative group modulo $p$. The demerit of this approach seems ...
1
vote
0answers
38 views

What is the maths behind Bitcoin's BIP32?

I've read about BIP32 key derivation functions. I'm trying to understand how, given a secp256k1 key pair, that "child" public keys may be generated from just the public key, and the ...
0
votes
0answers
20 views

A zero knowledge protocol with a deterministic verifier

Given a language $L$ and $ZKP$ between $v$ and $p$, when $v$ is deterministic polynomial time algorithm, I wish to obtain a probabilistic-polynomial algorithm which solves $L$. Which, if I am not ...
1
vote
1answer
65 views

Frequency Analysis on DES, AES, 3DES using Cryptool2

I am trying to analyze symmetric block ciphers like DES, 3DES and AES, using Cryptool 2. I want to do a frequency analysis on each of these ciphers, in order to comment whether this is an effective ...
0
votes
1answer
42 views

Why do we add error in the definition of LWE?

One of the various equivalent definitions of the LWE problem is the following: Let $n,q$ be integers ($q$ usually is a prime number), $\chi$ a discrete probability distribution over $\mathbb{Z}$ (...
1
vote
2answers
349 views

Is it fair to say that MACs use a signing algorithm?

The Wikipedia page on MAC calls the algorithm that is used to generate the MAC as a signing algorithm. Is that a fair use of that term? Can we then say that HMAC-SHA-1 uses SHA-1 as the signing ...
1
vote
1answer
35 views

Hash into elliptic curves for private set intersection

Would it be insecure to hash a message $m$ to an elliptic curve point by multiplying it to some generator $G$ for the purpose of a private set intersection ? $$ M = hash(m) * G $$ I keep seeing ...
1
vote
0answers
30 views

Why ideal lattices?

An ideal lattice is a lattice $\mathcal{L}(A)$ generated by a block matrix $A = \left[ A^{(1)} \mid \dots \mid A^{(m/n)} \right]$ whose blocks $A^{(i)}$ are constructed from a vector $a^{(i)}$ and a ...

15 30 50 per page
1
2 3 4 5
446