Questions tagged [rsa]

An asymmetric (e.g. public-key) cryptosystem, based on modular exponentiation with big exponents and modulus. RSA can be used both for signature and encryption with proper paddings.

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Is the verification process in ECDSA the same or different from in RSA?

With an RSA key pair, from my understanding, Alice who holds the private key is able to encrypt a message into a signature. She would then send the signature together with her original message to Bob. ...
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breaking RSA with linear padding using Hastads attack with e>=11

I have been playing around with Hastad's broadcast attack on RSA with linear padding. Using the implementation and the test function from here: https://github.com/0n5/CTF-Crypto/blob/master/RSA/...
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layout scheme to store encrypted files

I'm working on a little hobby project to better understand crypto. https://app.gitbook.com/@noojee/s/dvault/ The aim is to make it easy to encrypt a set of files into a 'vault' and decrypt them at a ...
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RSA security when using short messages

We know that a short message encrypted with RSA can easily be brute forced. Lets say Bob encrypts a message containing just "Hi" and encrypts it with Alice's public key. Anyone can try ...
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Encrypt private key and decrypt with the public key

Is it possible to encrypt with the RSA private key and decrypt with the RSA public key(not for signature) The task is that I have to encrypt the data with a private key. Transfer this data to another ...
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RSA Private Exponent Generation according to FIPS 186-4 in openssl v1

I guess this is more of a math problem in a cryptography context so I apologize beforehand if it is not the right place to ask. Basically I have to check whether a certain implementation of RSA key-...
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What are the security implications of RSA decryption of ciphertext >= modulus?

While reading through the sections about decryption in PKCS#1 v2.2, I noticed that the decryption algorithms are required to output the failure symbol: ...
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What is here the security parameter $1^\kappa$?

Let it be $K$ a key generation algorithm which takes $(k,d)$ as input with $k$ as the bit length for $n=pq$ with $p,q \in \mathbb{P}$ and $d=|p-q|$ as the minimum distance between $p$ and $q$ (RSA). ...
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RSA factorization knowing the form of p and q

I'm wondering if knowing the form of both factors (p and q) of a RSA modulus N is a significant help for factoring or not. For instance: p of the form 4k+3, so (p-3)%4 = 0 and q of the form 4k+7, so (...
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Coursera Course or book(s) That covers the following subjects: OPENSSL, SSH, PKI, MD5, RSA, Certificates, keys, signatures

I started working as a developper in a cryptography company 3 months ago where the applications are for mostly windows applications. I found that I don't have enough knowledge concerning the topics ...
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Should strong RSA key with SHA1 self-signature in public key to be considered weak?

Older RSA-4096 GPG keys generated when SHA1 still thought to be acceptable have public key self-signed with SHA1. Shall this considered to be weak key? And with what arguments? AFAIK, GPG key ids are ...
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Is it possible to de-anonymize user in RSA blind singing without knowing the random blinding factor only?

For example, in case of using RSA blind signing in E-Voting protocol: Is it possible to trace (Sx, x) to (Sb, b) if Signer and Tallier is the same person? In this case, attacker has access to: ...
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Question on double-asymmetric encryption and split knowledge

Moin moin, Let‘s assume there are two keypairs (d1,e1) and (d2,e2), where d1 and ...
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RSA use prime p as public exponent

I've got two 1024 bits prime $p$,$q$,and $n$ = $p$ * $q$. now I know the result of $ c^{p} \quad mod \quad n = x$,also the value of c is given, I wonder if it is possible to factorize $n$.
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In RSA signing find n from e and many pairs of m and c

When signing using RSA with $e = 65537$ and many pairs of m and c, where $$c^e \bmod (n)=m$$ is there a way to find n (n is 2048 bits)? I planned on computing $ c^e-m $ and then treating those as a ...
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How are the instantiations of RSAES-OAEP and SHA*WithRSAEncryption different in practice?

For the spare-time project I had been working on, I'm evaluating the PKCS#1 padded RSA schemes for implementation. For PKCS#1 v1.5, encryption doesn't seem to require a hash function, and the ...
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RSA short key generation using OpenSSL

To write a CTF challenge, I want to create an RSA key pair of size 228-bit. I want the keys exactly in the same format as OpenSSL-generated keys. But, OpenSSL is not supporting less than 512-bit long ...
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Is it possible to apply RSA on complex numbers?

RSA is a popular public-key cryptography algorithm. It has some mathematical assumptions. I mean, one cannot apply RSA on elements of any algebraic structure. Elements from certain algebraic ...
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RSA given n % (q-1)

I am trying to work out an RSA challenge where I am given n, e, c and the result of n mod (q-1) However, I can't wrap my head around the maths. Could anyone help?
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What information is needed to be stored for RSA private key for decryption

I am using rsa module in Python. I use the following line to generate public and private key: ...
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Difficulty of computing RSA keypair with given bits preset

Given a 2048-bit RSA public key physically burned into hardware, is it feasible to find a keypair where the public key could be "overlaid"? To detail, each bit in the hardware key is write-...
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What's the use of storing R^2 with a public key?

I think I have successfully reverse engineered a Samsung RSA public key here. However, the public key mainly seems to consist of the modulus, but it also contains a 32 bit integer ...
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Samsung .Cert File - Digging deeper

I don't know if I should ask this question in Android Stackexchange or here, but I am sure I am in a right place to ask. My question is about following Samsung Certificate file: File name: ...
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RSA DECRYPTION when N gives only one prime number

I am getting only 1 prime factor to some power if i factorize N for RSA decryption. So, in this case what will be the value of P and Q. P will be that one Prime Factor and then there is nothing left ...
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How to generate large integer private key for creating CTF challenges?

I am trying to create a RSA CTF challenge, exposing $n$, $e$, $c$, and $d$. I have set $e=65537$ and $n = p * q$ where $p$ and $q$ are large primes each with 300 digits. I have determined $c=m^e \mod ...
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Decrypt RSA with known public key and modulus and the range of dp

How to decrypt RSA while given $e$,$n$ and the range of $dp$ ? ...
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Can the hash of a PKCS1 v1.5 RSA signature be used as a key derivation function?

I know this sounds crazy, but hear me out. As a follow-up to Can the AES-GCM authentication tag be used as a key derivation function?, I'm also considering more creative solutions to derive unique (...
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How to hack pass-protected private RSA key

I know nothing about cryptography. I must present a completed ASP project to my university that proves I have learned clingo. I have heard that the task of recovering the plaintext private RSA key ...
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Zero knowledge RSA public key

Suppose Bob has $k>1$ RSA public keys $(e_i, n_i)$ without any knowledge of their corresponding private keys. Alice also has all the public keys, but also has a private key for only one of them, ...
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Cracking RSA (or other algorithms) manually by a savant

RSA cryptography strength comes from the hardness (or so we believe) of factoring big numbers. For key lengths over 2048 bits, it is infeasible for current or near-future computers to factor those ...
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Factoring RSA when reusing N

Suppose in two RSA instances the same $p,q,N$ are used, but different public keys $a,b$ (and corresponding private keys) Suppose now we have the two equations $c_{1}=m^{a} \bmod N$ $c_{2}=m^{b} \bmod ...
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Is the relationship between private and public keys an example of bijection between two sets?

Just want to make sure that my understanding is correct whether there is only one public key for any private key, and vice versa. I know that there are many algorithms, and this may not be a property ...
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Bleichenbacher CCA, proof of termination

I am currently thinking about how to prove that the algorithm presented in Bleichenbacher's paper (http://archiv.infsec.ethz.ch/education/fs08/secsem/bleichenbacher98.pdf) actually terminates. I know ...
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Schnorr RSA factoring (round 2)

Introduction Earlier this year Claus Peter Schnorr claimed to have "broken RSA". The original paper was discussed in Does Schnorr's 2021 factoring method show that the RSA cryptosystem is ...
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Can you please explain how Manger's attack against RSA OAEP works?

I searched but found nothing except the original paper, and I can't wrap my head around it. Can you help me by giving an overview and then if possible, a short explanation of the algo?
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Is "Fast Factoring Integers by SVP Algorithms, corrected" correct?

Schnorr comes again. Will he really break RSA this time? But he still didn't give any concrete examples that can enable us to quickly verify his claim.
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Factors calculation in RSA

You are given $d\bmod(p-1)$ , $d\bmod(q-1)$ , $\operatorname{invert}(p,q)$ and $p\bmod2^{200}$, the public exponent is $e=65537$. $\operatorname{invert}(p,q)$ is the answer of $ p*x \equiv 1 (mod\quad ...
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Completing RSA Encryption

Being new to cryptology, I'm trying to understand how I would complete RSA encryption by hand. I can only follow the formula so far before becoming very confused. I want to encrypt the value "123&...
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How is it possible to derive the public exponent from an RSA private key?

I am gonna write down formulas that I know and use to generate RSA keys. we choose $p$, $q$ $N = p\cdot q$ $\varphi(n) = (p-1)\cdot(q-1)$ choose $e$ such as $1 < e < \varphi(N)$ $e$ is coprime ...
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Interval for PKCS#1 v1.5 compliant plaintext

In Bleichenbacher's paper (http://archiv.infsec.ethz.ch/education/fs08/secsem/bleichenbacher98.pdf, section 3.1) he concludes that if m*s is PKCS#1 v1.5 compliant we get the following interval: $2B \...
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Why is ECDHE safe when paired within signing?

I wanted several videos by Computerphile on Elliptic Curve Diffie-Hellman, digital signatures and TLS. For the most part I understand everything but something is bothering me. Computerphile made a ...
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Has there ever been any real world consequences of using probabilistic primality tests for RSA or other similar systems?

Considering the huge amount of RSA certs which have been generated, wouldn't there probably be a small number of certs where one of the primes which may have actually been a composite? Has this ever ...
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End to end encrypted chat design

I am in the process of creating a flutter application that will include direct messaging. You can message 1 person or a group of people. I want this to all be encrypted for privacy. The method I was ...
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How do you find RSA encryption key e?

How do you find RSA encryption key e when RSA modulus is n = 55 = 5 x 11 and your decryption is d = 37? Is this possible for large values of n say of the order of 1024 bits?
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PRNG For RSA (ANSI_X9.31)

I have a query please , I want to know how to generate random numbers using ANSI_X9.31 algorithm for RSA Algorithm please . Thank u
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Why does it take more time to decrypt the same file with 256 bit RSA in TEE than in REE?

We all know that TEE can utilize almost all of the CPU's performance, so its time spent encrypting files using RSA256 is less than that of REE. But why isn't decryption? Why does it take more time to ...
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Verifiable Delay Function: Trusted Setup

Efficient Verifiable Delay Function paper suggested that there is two way to construct the group. One of them requires trusted setup in the sense whoever constructs the RSA unknown group order needs ...
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Zero-Knowledge Proof of Equality between RSA Modulus and Prime Order Group

Assume there is an RSA public key $(e,n)$ such that factarization of $n$ is unknown to both prover and verifier parties. We also have a prime order group $G$ and a generator $g$ for the group. For $m\...
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CrypTool RSA Features [duplicate]

I am attempting to manually encrypt a plaintext message (message = MI) using RSA. I receive an answer of: 33,264 and 21,164. When I enter the same plaintext into CrypTool to confirm that my ...
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Am I Doing RSA Correctly?

I am trying to figure out how to complete RSA manually. I am trying to encode a simple block message (Mi). I used CrypTool to determine the encryption. When I "manually" computed the ...

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