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

In Section 2 dP and dQ are defined thusly: ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ,...
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### 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 = ...
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### 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 ...
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### 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?
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### 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 ...
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### 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 ...
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### 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, ...
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### 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 ...
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### 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 \\...
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### 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 ...
314 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)? ...
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### 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 ...
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### 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. ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 ...
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### 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 (...
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### 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), ...