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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 ...
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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 ...
18 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 $\mathbb{Z}$ (...
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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 ...
21 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 ...
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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 ...
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Is $f_N$ in this hash function is Matyas-Meyer-Oseas scheme?

I propose a hash function as following: H is an Merkle-Damgard hash function with a compression function $f: \{0,1\}^{3n} \to \{0, 1\}^{2n}$. Output function $f_N: \{0,1\}^{3n} \to \{0, 1\}^n$. M is ...
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Isogeny-based AKE: what is the difference between Gal 1 and FTTY 1?

What is the difference between (a) the AKE scheme proposed by Galbraith (based on TS2 protocol) in https://eprint.iacr.org/2018/266.pdf (page 9-10); and (b) the AKE scheme proposed by Fujioka et al. ...
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Curve25519 extension field

The paper regarding curve25519 presents a theorem in chapter 2 (specification). The extension field $F_{p^2}$ is used in this theorem. I don't understand why this extension field is needed for the ...
36 views

How do I encrypt a long message using ElGamal encryption correctly?

According to ElGamal encryption, in order to encrypt a message I need to generate a shared secret s and after that I am to calculate ...
17 views

How to prove properties of pre-image of random oracle in zero-knowledge proof?

A signature Sig is given as input to random oracle H, such that y = H(Sig) and Sig should be hidden from the verifier. How to prove in zero-knowledge to the verifier that y is the correct output from ...
46 views

RNG randomization strength for PRF seed

Consider a use case that requires the creation of multiple asymmetric key pairs. There are two options for generating random seeds for a PRF: Use a software based RNG and generate a new seed for each ...
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What papers describe the rationale behind cryptography algorithms

I am trying to introduce myself to cryptographic hashing and encryption. I am looking for original papers of sorts, to describe the inspiration behind why they choose certain numbers, if they are ...
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Is it possible to create a 128-bit UUID from a weak entropy source?

I am looking at a seemingly popular piece of JavaScript code to generate a UUID which is supposed to be a 128-bit number: ...
381 views

Calculating RSA Public Modulus from Private Exponent and Public Exponent

If I know the private and public exponents ($d$ and $e$) of an RSA key pair, is it possible to (efficiently) calculate the public modulus $n$?
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Prior art: SSH key authn over TLS?

I’m developing an application that runs over TLS. In addition to password-based authentication we’d like to be able to use SSH keys. Is there any prior art in using SSH keys for authentication over ...
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Functional signatures vs homomorphic signatures

I found that homomorphic signatures allows an agency to carry out arbitrary computation $f$ on the signed data $m$ and accordingly gain a signature for the computation result $f(m)$ with respect to $f$...
60 views

Sensible amateur usage of web crypto API

I want to know if my usage of the web crypto API is sensible. I want to use it for symmetric and public-key encryption and decryption, and signatures, but as a non-expert I am scared by the warning on ...
54 views

Is storing salts encrypted a good idea?

I've read that storing password hashes in a database, you can store the salt in plaintext alongside the actual hash with no detriment to security. I was thinking that one could derive a key from the ...
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The Security of AES-N-GCM

In the paper The Security and Performance of the GaloisCounter Mode(GCM) of Operation,it shows the AES GCM SECURITY in Corollary 1. But I can not get the same result (the right corollary) from the ...
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Can I find a number, such that the its SHA-256 hash is all-0 [duplicate]

I want to find a number, such that the result of its SHA-256 hash is all 0. I don't know if this number exists.
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Can we defends against RSA Timing attack when we use java.math.BigInteger.modPow?

I think that Montgomery and sliding window techniques are applied within java.math.BigInteger.modPow (and more specifically ...
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CVC-PKCS#10 Generation and Signing

Good day, I have gotten a task at work which has turned out to be a rather interesting nightmare because of the lack of Information on the topic. My task is as follows: In order to ensure an ...
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RSA How many value for d

How many value can have a private key with this format? p,q,d = (19, 41, d) where 1< d <18x40? I want know how to calculate that.
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What is the difference between security parameter and $b$-bit security?

In a previous question, I read ... for $b$-bit security meaning $O(2^b)$ work for an attacker to break the system... While in Katz's Introduction to modern Cryptography, I read: The key-generation ...
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How to estimate the computation overhead of ECDSA?

I am using ECDSA as a digital signature scheme. Using Charm, I got the timing for the multiplication, exponentiation, and pairing operations; they take 0.005, 9, and 4.4 ms respectively. I want to ...
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Montgomery Multiplication with CRT

I am attempting to understand how to use Montgomery multiplication in an RSA private key operation: $X \equiv a^{e} \pmod{n}$ where $a$ is the message, $e$ is the exponent, $n$ is the modulus. Using ...
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Designing number of rounds of specific hashing process [closed]

Consider a certain encryption process/hash function which transform 128-bit blocks into 128-bit blocks. This is not a cipher or complete function yet. I am thinking about the theoretical process. We ...
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Multidimensional meet-in-the-middle attack on AES

Is an MD-MITM attack possible for AES? As I know, we can break 2 rounds of AES. So we could apply the MD-MITM attack 5 times. This should significantly reduce the security of AES. What stops us from ...
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How hard is it to link a hardened BIP32 child public key to it's parent public key?

The BIP32 spec says this in the security section: ...
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My question is about Enigma rotors

I found this explanation of Enigma rotor movement on this website, but can't quite understand the methodology: Enigma rotation example A ⤑ B → D ⤑ C (rotor III in position B) C ⤑ C → D ⤑ D (rotor II ...
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How to fix the issue with Gimli full permutation distinguisher?

A new paper "New results on Gimli: full-permutation distinguishers and improved collisions" has been published stating a full 24-round permutation distinguisher with a cost of $2^{64}$ and ...
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OAuth(2) and friends

I've worked on low-level security (side-channel attacks etc.) for years and have a PhD in crypto. Web security is something I've never needed to touch beyond knowing how the TLS handshake works with ...
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How to generate Multiple Encryption Keys for use in RSA polymorphic multiplication

I am a long time scroller, first time poster in the crypto stack. I've recently been finding myself leaving the realm of mainstream/standard crypto (imo that consists of symmetric/asymmetric ...