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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Rsa encryption security

What tool is used to measure the security of rsa encryption? If no, is there any tool to measure rsa encryption in terms of security. Or any idea how to measure security of rsa encryption?
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about rsa decryption with given n,e,2d+phi(n)

I have given n, e, c, and 2d+phi(n). any idea how to proceed to solve that RSA. for values click on this:- https://pastebin.com/mdeSdfzD
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Can duplication of encrypted characters lead to a weakness in RSA?

Of course, I know RSA is to widely used and tested to have any legitimate threats, but I still am confused by this. I have been trying to implement C++ (in a effort to learn how it works, not to be ...
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Is it possible to generate random bits to be imported as a private key and then deducing his public key?

Is it possible to generate random bits (or any bits we decide) to be imported as a private key and then deducting his public key please? Ideally with a supported Javascript WebCrypto algorithm ( ...
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How secure is RSA for authentication?

I'm building a web-based password manager system and would ideally not send sufficient information to the servers to decode the raw text passwords of users. The plan is to encrypt the raw text ...
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655 views

How to encrypt video using RSA [closed]

I can encrypt the message using the RSA algorithm. But I do not know how to encrypt video.
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RSA and format of numbers

When calculating the initial values of p,q,n, etc. in RSA, what base are the numbers? Are the numbers stored in binary, hex, or just simple base 10 when doing the modulus calculations? Additionally, ...
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487 views

How expensive is the Extended Euclidean Algorithm?

Given a private key $k$ and a modulus $n=pq$, where $p \neq q$ are two very large prime numbers, we find the value of Euler's Totient Function $\varphi(n)=(p-1)(q-1)$. The public key $K$ is given by ...
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The improvement of the private key exponent in the M.Weiner Attack

I am working on attacks on RSA and came across the M. Weiner attack. The limit for $d$ in order for the attack to apply is $d <= (\frac{1}{3})N^{0.25}$. The paper states that Boneh and Durfee ...
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Assuming that we had a way of finding primes, could RSA be used without computers?

I once asked a question "Would RSA make sense if we used no computers?". The answer was negative, because finding primes that would make secure keys would prove too hard. Assuming that we had found ...
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Encrypting with private key in Public Key InfraStructure [closed]

In Public key infrastructure, the MD5 of a piece of data is encrypted with the private key of a sender and this encrypted MD5 – along with the data – is again encrypted using an algorithm like AES or ...
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How to declare 2048 bit key in RSA

I want to implement RSA algorithm using C language. I have read the size of primes in RSA like p and q are 2048 bits long. How to declare such 2048 bit values in C. As i know that the data types like ...
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RSA exercise with known $n$ and $e$

Bob decides to use $n = 697 \rightarrow 17 × 41$ and $e = 33$ as his public key for an RSA cryptosystem. Show that the decryption exponent is $97$. Find the encrypted form of the message $17$.
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RSA limiting down the possible values for $n,q$, and $d$? given only $e$ and $p$ [duplicate]

Suppose someone forgot the value of $n$ and you only knew the values for $e$ and $p$. How could one go about limiting down the possible values for $n,q$, and $d$? I'm thinking to try and solve $\gcd(...
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I am new to digital certificate 509V3 concept. can some one please clarify the below points [closed]

I am using RSA 2048 with SHA 256 primitive in certificate: How to verify the user certificate n + 1 with Root certificate n? why it is required to perform Certificate chain verification? How to ...
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RSA Security -textbook question

One of the attacks on plain RSA involves a sender who encrypts two related messages using the same public key. Formulate an appropriate definition of security ruling out such attacks.And show that any ...
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Cracking RSA message with shared modulo but different e while knowing one of the private keys

How can one crack a message c_2 encoded by e_2 if one knows e_1, e_2, d_1, and both codes share common modulo n, without using factorization? Considering textbook RSA
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Is possible to retrieve RSA d knowing m, c, e , n?

I have a scenario that has this type of security: System A generates a random number and sends it to B ...
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108 views

Mathematical RSA clarification [closed]

I'm trying to teach myself cryptography and I know that RSA is a large part of this topic and stumbled across the following question which I feel if clarified would help me understand a large part of ...
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RSA problem - how to find $d$ [duplicate]

For example, let $p = 3$ and $q= 11$, choose $e = 3$. What computation I have to apply in order to find the corresponding $d$? I know it's 7, but I want to know the exact process to be applied to find ...
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Openssl library problem

I'm using openssl library and I've a problem with RSA_private_encrypt() and RSA_public_decrypt(). I'm using a key size of 256 bit with no padding of the input message. I've noted that when my input ...
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Montgomery and Galois fields

I'm a little bit confused about the design of a RSA module in VHDL. My question isn't directly related to hardware design. I've read a lot of publications and I bought also a book. In one publications ...
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why RSA uses Semiprime numbers? [duplicate]

Why does RSA use semiprime numbers? Why not just use any big number ?? What is the advantage of the two original numbers being prime? Because factoring any big number will be difficult
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Can someone explain how this unpadded RSA formula works?

Taken from http://en.wikipedia.org/wiki/Homomorphic_encryption, $\mathcal{E}(x_1) \cdot \mathcal{E}(x_2) = x_1^e x_2^e$ $\bmod\; m = (x_1x_2)^e \;$ $\bmod\; m = \mathcal{E}(x_1 \cdot x_2)$ What is ...
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Security of RSA-substitution-RSA

Following on from here, I am unconvinced that encrypting twice with RSA is a waste of time: doesn't it depend on what is placed in-between the two encryptions?. What would happen if a permutation was ...
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How to calculate base value in modular exponentiation

If you have $a^b \bmod n = c$, and $b,n,$ and $c$ values are given, is it possible to find a value for $a$ within a given range? So is it possible to find $a$ in $a^{2051} \bmod 3149=636$ knowing a ...
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Decrypt AES key with RSA public key

So here's my problem: I have 3 files. One is ciphertext.enc, which is a text encrypted using AES 256. The second one is ...
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RSA : if my key and message are too large , how to do?

I want to send a message consisting of a string of number (e.g: 124124134235235) Then, p:125243 q:56454547 e: 2659043 d: 5261378624675 However, it will be too large...so, is there any solution to ...
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How to generate sha 256 hash using https url

I want to generate sha256 hash of https url. ex: url "https://www.google.com/" I want sha hash of this url. I have tried extracting public key from ssl certificate and used following command. ...
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Can I calculate $d$ given only RSA’s $c$, $n$ and $e$?

The question “Calculating RSA private exponent when given public exponent and the modulus factors using extended euclid” assumes the factors are known. This got me wondering if it is possible to ...
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Comparison of RSA and DRSA scheme using SageMath

I am trying to compare the encryption and decryption speed of the RSA and the DRSA scheme with same public key $(n, e)$ and private key $d$ (using SageMath). For $1024$ bits long $n$, I got the ...
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RSA encryption with private key, decryption with public key (again) [duplicate]

First of all let me point out that I am aware of all the theory behind asymmetric encryption and signing, and other related areas like signcryption, etc. It seems that mathematically it is possible to ...
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What is contained in a RSA key file? [duplicate]

Consider a RSA key file like this: ...
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Generate private key from public key RSA

I am doing a tutorial where my lecturer (PhD) gave me an optional question to do relating to RSA. He said: write a python function that takes as input the server’s public key and then uses that to ...
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Integer Factorisation

If I have a set of numbers of the form $\{ {kp+r}:k\geq0\}$ with p a prime or product of primes k large in $\in Z^+$ and r fixed, is it computationally feasible to find a factorisation for any one ...
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Why do RSA public keys begin with 3048024100?

RSA public keys seem to begin with 3048024100, why? They also seem to end with 0203010001
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moduli in SSL certificates [closed]

this is normally seen in a typical SSL certificate. For the modulus, I know that it is represented in hexadecimal form, but why is there a semicolon (:) after every group of 2 digits? ...
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How to write the encrypted message after using RSA

I have created a RSA encryption/decryption program but how do i write out the results after doing a encryption? Right now I have it so that it will just print out the decimal value of one character ...
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RSA - What to do when message is greater than N [duplicate]

Exmple: $e=3, n=33$ and $d =7$ and Message is $64$.
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PowMod in single step

I am trying to figure out if it is known how to calculate PowMod for a specific number of iterations in a single calculation. For instance take following function. m^e mod N m is a plaintext value e ...
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Find a constant $C$ in $O(Cn^2)$?

I am writing a paper on RSA, and I am calculating some encryption running times. I have been told that the encryption running time is $O(n^2)$ where $n$ is the modulus. I have also been told that ...
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Cracking plain RSA by factoring the modulus n

This is the setup: I have both public and private keys of one "instance" of RSA. And I have only the public key of another RSA cryptosystem, but this system has the same modulus as the first one. I ...
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crack RSA encryption

According to Wikipedia RSA definitions are : so we have $n$ and $e$ because $p$ and $q$ are prime so there is only one $p$ & $q$ which fit to n so from n we can have $p$ and $q$ so we have $\phi(...
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cracking any know algorythm [closed]

So, I know what algorithm is used for a secure connection with TLS v 1.2 for eg. And say I know what websites a person is using for eg me. And I also know what packets that website is sending ofc. ...
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Speed of a 16384-bit RSA key

I don't think it makes much sense to use RSA keys to authenticate the establishment of symmetric keys with strengths less than their own. From what I know, a 16384-bit RSA key's strength is roughly ...
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What parts of number theory does the RSA algorithm use?

It is said that the RSA algorithm uses number theory. What parts of number theory does it use? I know it uses modular arithmetic and Euler's totient theorem and function. Is that all?
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Are there any flaws in this pseudocode?

I'm developing an algorithm that cracks small RSA keys (And theoretically bigg ones too, though might take some time), and was wondering if anyone you spot any flaws in this python code: ...
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side channel attack on RSA [duplicate]

A side-channel attack is any attack based on information gained from the implementation of Encryption protocol and by monitoring security-critical operations. Almost every encryption had a side-...
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RSA Time Complexity on Best Case, Average Case and Worst Case

I am currently learning the work arounds about RSA algorithm. I wanted to know the time complexity of the encryption part and decryption part on Best Case, Average Case and Worst Case. Im new in ...
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Which curve is used for ECDH

I heard about the problem choosing between ECDH vs. RSA. But as far as I know, RSA can encrypt the key and sign it. So for ECDH to replace it it has to do both. But which elliptic curve is used for ...