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.

Filter by
Sorted by
Tagged with
0
votes
2answers
58 views

what are security reductions of symmetric-key algorithms?

I was reading Wikipedia page of post-quantum cryptography. It says that it is desirable for cryptographic algorithms to be reducible to some particular mathematical problem, that is intractability of ...
0
votes
1answer
62 views

Pretty much confused about pretty good privacy-:

Authentication-: I understand that authentication is basically digital signature. But what I don't understand is how it has been explained here specially the RSA key part. It is leading me to huge ...
-1
votes
2answers
75 views

How to decrypt a file using RSA and just a public.pem file?

I have an encoded file and a public.pem file. Is it possible to decode the file using the public.pem file or do I have to start looking at private keys? I tried https://github.com/Ganapati/RsaCtfTool ...
4
votes
1answer
85 views

Would being able of factoring integers efficiently have some consequences over Elliptic Curve Cryptography?

Let's assume you can factor integers in a very efficient manner. Would that endanger the security of e.g. elliptic curve cryptography, or is there no link between the two ? You can often read that ...
1
vote
1answer
52 views

conflicting definitions for dP / dQ and exponent1 / exponent2 in PKCS 1?

In Section 2 dP and dQ are defined thusly: ...
0
votes
1answer
59 views

Eavesdropping attack on text-book RSA encryption with public nonce

Consider the following scenario: Alice has a secret key and public key pair for text-book RSA (denoted $\text{sk}$ and $\text{pk}$ respectively). Bob has an authentic copy of $\text{pk}$. The ...
1
vote
0answers
52 views

Does SHACAL-2 have collision resistance?

I am trying to find if a design of mine SHACALheader(payload) ⊕ header will have more collisions than if we just concatenate Hash(datagram) := H( H(header) || H(payload) ) ? I am fairly new to ...
0
votes
0answers
30 views

How is this step being calculated and why is that getting the factors is able to determine private key or universal forgery?

https://link.springer.com/content/pdf/10.1007/3-540-49649-1_18.pdf In class I, why (4) implies $g\equiv 1 \mod q$ Also even though I get $p$ and $q$ it still can't get $ord_n(g)$ without trying out ...
0
votes
1answer
39 views

How to find iteration exponent in a cycling attack?

In Simmons and Norris paper they demonstrate the cycling attack with the following example: p = 383 q = 563 s = 49 and t = 56957 ( a prime) The attacker knows the publicly available r = pq = 215,629 ,...
-3
votes
0answers
39 views

How do you quickly find D? (RSA) [duplicate]

with small primes under 1000 each i can find D in a matter of less than 1 second but anything above 1000 seems like it could go on forever! right now I generated huge primes (p = 9504941263, q = ...
0
votes
1answer
55 views

How to ensure the data comes from verified source without using asymetric encryption

I'm building a project that is remotely controlled using LoRa and I want to ensure, that nobody can imitate my transmitter and send packets to my receiver. Just encrypting sent data is not enough ...
3
votes
1answer
49 views

Question about white-box rsa algorithm

I found a scheme for white-box RSA. It seems to protect the input and output of modular operations. I'm curious about how to analyze the security of this solution. Does anybody know anything about it?
3
votes
2answers
106 views

Why is confusion and diffusion never talked about in asymmetric crypto?

While talking about symmetric encryption schemes like AES we always have a goal of achieving confusion and diffusion. But when it comes to asymmetric encryption schemes like RSA, DH etc. we never talk ...
3
votes
0answers
79 views

No Final subtraction in Word-level Montgomery Multiplication

I am trying to make an RSA module in VHDL, which in turn will be deployed to an FPGA. I am trying to implement a full Montgomery algorithm which means that I am working with the Montgomery ...
1
vote
0answers
53 views

Comparing complexity of RSA decryption with/without CRT

(Cross-listed on math stackexchange, received no replies) For context, this is a homework question from an assignment already turned in. I am looking for better understanding of the concepts involved, ...
1
vote
1answer
74 views

What are those RSA Challenges, DES Challenges and RSA Factoring Challenges

Can someone explain the differences between the DES challenge, the RSA challenges, and the RSA factoring challenge? What were the aims? I think the factoring challenge was to encourage research, the ...
1
vote
1answer
126 views

Why does Shamir's Trick for RSA Work

I have read that Shamir's trick can protect RSA with CRT against fault attacks. However, it is not clear to me why the following equations $$ s_{p}^{*}=m^{d \bmod \varphi(p \cdot t)} \bmod p \cdot t \\...
1
vote
1answer
78 views

Multiuser encryption, singleuser decryption [duplicate]

I have an hybrid encryption (RSA, AES) for a file sharing project I am working on, where I use a single public key for encryption on the sender side and corresponding private key for decryption on the ...
3
votes
3answers
324 views

Is there an easy way to make textbook RSA secure enough so it can be used in real life?

I have written a raw (textbook) RSA implementation (just for fun) and I wonder is there an easy way to make it secure enough so it can be used in real life (without implementing OAEP+ and RSASSA-PSS)? ...
0
votes
1answer
35 views

Simple Key Exchange, One Server

I am trying to better understand how TLS works. I understand in the normal use case you need various random values generated and used in the key exchange, to prevent some MITM reusing a previous ...
0
votes
1answer
91 views

Does the signature length of RS256 depend on the size of the RSA key used for signing?

The following NodeJS code, when run (v16.8.0), logs 512 to stdout. ...
7
votes
1answer
152 views

How bad is it to leak $k$ in RSA?

In RSA using a small public exponent $e$ such as $65537$, how bad is it if the value $k$ leaks? $k$ as in the following equations: $ed - 1 = k \phi(n)$ or $ed - 1 = k \cdot \operatorname{lcm}(p-1,q-1)...
2
votes
1answer
68 views

Need help to understand RSA common modulus attack to get private key

I'm learning about common modulus attack and learned that public modulus attacks can find out the private key. Assume there are 2 users with public and private keys $(e_1, d_1)$ and $(e_2, d_2)$. ...
0
votes
1answer
71 views

RSA: why $( e^{-1} ~\text{mod}~ n \cdot \varphi(n)) ~\text{mod}~ \varphi(n) = e^{-1} ~\text{mod}~ \varphi(n)$ holds for a specific setting of RSA

Let $p,q$ are primes and $n = pq$ as in every RSA setting and now use a random $e$ that holds the following properties $gcd(e, \phi(n)) \neq 1$ $(e^{-1} ~\text{mod} ~\phi(n))^{4}\cdot3 < n$ $e^{-1}...
0
votes
1answer
37 views

RSA Blind Signatures Secure Implementation

note: I am not a crpytographer I want to check if my RSA Blind Signatures Implementation is secure to be used in a production-stage application and I also have some questions which I would be so ...
0
votes
0answers
108 views

Textbook RSA meet in the middle time complexity

Hello, I have a question regarding time complexity of meet in the middle attack on textbook RSA encryption. Let's suppose that I try to encrypt symmetric keys of different length with no padding using ...
0
votes
1answer
113 views

Why a private key is used to encrypt hash in digital signing

In common RSA encryption, a public key is used to encrypt message, and private key decrypts it. However, in digital signing, it's the other way around: Bob hashes his message, then encrypts the hash ...
1
vote
2answers
80 views

RSA encrypt an AES key. What about the AES IV?

I need to securely pass an AES key to a remote client. What I did so far is to generate a random AES key and encrypt it using the RSA public key of the client (PKCS#1 v1.5 padding is taken care by the ...
0
votes
2answers
49 views

Generation of RSA key pair and storage of only private key PKCS#11

I noticed that the PKCS#11 supports C_GenerateKey function for symmetric keys and for asymmetric there's only C_GenerateKeyPair ...
1
vote
1answer
92 views

RSA key generation: why use lcm(p-1, q-1) instead of the totient ϕ(n)?

As far as I can see, generating a private key from two prime numbers p and q, having calculated ...
0
votes
0answers
52 views

RSA implementation not working with large values for plaintext [duplicate]

While implementing RSA encryption/decryption (using python), the plaintext doesn't match with the decrypted ciphertext for large values of plaintext. Works fine for smaller values for plaintext (...
1
vote
1answer
95 views

Break RSA without padding using a rainbow table attack

We are using RSA without OAEP, with a relatively small input domain. Lets assume we have John and Bob connected on a line, and we are eavesdropping them. Bob first sends John his public key (e,n), ...
2
votes
1answer
108 views

Factoring a RSA modulus given parts of a Factor

e,N,c and around 2/3 of p are given and I need to get the whole p to decrypt c. ...
2
votes
2answers
183 views

Is this RSA-based IBE Scheme secure?

The PKG performs the following steps Choose $p,q \in \mathbb{P}$. Calculate $N=pq$. Calculate $\phi (n)=(p-1)(q-1)$. Choose $e$ with $gcd(e,\phi(n))=1$ and $1 < e < \phi(n)$. Let it be $e = {p^{...
-2
votes
1answer
80 views

RSA : recovering a few missing bytes in an almost complete plaintext

I have a RSA-4096 public key, a ciphertext, and almost the whole plaintext : there are only a couple dozens bytes missing near the end, or in other terms, I know the range 0-80% + 90-100% of the ...
1
vote
1answer
117 views

Specific case of RSA where cipher text equals plain text

How did they arrive at the conclusion that there are 4 messages where plain text equals cipher text from "It is easy to show that in RSA, when e = 3 there are 4 messages m for which the ...
0
votes
0answers
25 views

Authentication in P2P networks without central server

I'm trying to understand how to perform authentication in an P2P network without a central server. Given a network with no central trusted unit and a PKI, how can one be sure of the authenticity of ...
1
vote
1answer
159 views

Is RSA the only current practical option for asymmetric encipherment of symmetric keys at rest?

As of 2021, is RSA the only practical (i.e. safe, production-ready) option for asymmetric encipherment of symmetric keys at rest? ECDSA is obviously preferable over RSA in the case of signing, but (...
2
votes
1answer
178 views

Digital signature with Big Brother

I have read digital signature with Big Brother but don't understand the sequence. One approach to digital signatures is to have a central authority that knows everything and whom everyone trusts, say ...
4
votes
1answer
517 views

RSA the same message is sent with two different exponents , but exponents are not relatively prime

Hi I know there have been other questions like this on here, namely here. But of all the solutions I have seen of this problem, $e_1$ and $e_2$ are relatively prime, which is how we can get to the ...
1
vote
0answers
50 views

PKCS#7 digest encryption algorithm - difference between rsaEncryption and sha256WithRsaEncryption

As part of our linux secure boot implementation using dm-verity and root hash signature checking, I need to sign a file with the following openssl command (example): ...
0
votes
1answer
150 views

Is a RSA private key leak possible if I both sign and decrypt? [duplicate]

Is it possible to leak private key data if attacker control signing request ? Everyone know $N$ and $E$ because they are public. My server is designed to decrypt incoming request which is encrypted ...
-5
votes
2answers
68 views

RSA impossible to be factorized?

If the RSA numbers are odd, how can they be factorized by two primes, since a prime is only divisible by itself and 1?
0
votes
1answer
53 views

rsa attack with plain text, cypher text , public key

starting from the fact that there are different attacks on RSA, based on the starting situation, for example there are different studies, on attacks that find the private key having the freedom of an ...
1
vote
2answers
157 views

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. ...
2
votes
1answer
404 views

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/...
0
votes
0answers
18 views

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 ...
0
votes
1answer
93 views

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 ...
-2
votes
1answer
95 views

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 ...
11
votes
2answers
541 views

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-...

1
2 3 4 5
49