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.

1,826 questions
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In which public key encryption algorithms are the private and public key not reversible?

The RSA public key encryption system has the characteristic that the public key and the private key can be reversed. That is, information encrypted with the public key can be decrypted with the ...
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Encryption/Decryption on multiple users using RSA?

Supposing I have Alice that is the RA, Bob (who is a user) and Kate (who is also a user). For now I use RSA. Alice sends a message to Bob. Alice also sends a message to Kate. Bob and Kate exchange ...
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Alternate to distributing master key to every user in circle of trust

I am designing an end-to-end encrypted file storage system where only the user should be able to access their own data. The best I could come up with is a system designed around a master key that is ...
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Why do we need Euler's totient function $\varphi(N)$ in RSA?

After we calculated $N = p * q$, we calculate $\varphi(N)$ and use it later to determine $e$ (PR) and $d$ (PU). But why? For decryption and encryption we only use $N$ and don't need $\varphi(N)$. So ...
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Is there an equivalent to an RSA UFO in lattice-based cryptography?

So there's this concept within the realm of RSA cryptography called an RSA UFO. It is an extremely important function in the context of cryptocurrency. When starting up a cryptocurrency the creator(s) ...
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What is the “most secure” way to public/private encrypt a 64 bit value? [closed]

I want to encrypt a 64-bit value using a private key. The data size is limited to 64-bit, so the encrypted data must also not exceed the 64-bit limit. The receiver of the encrypted value should be ...
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If I want site engineer to export data having it encrypted and should be able to read as well as upload it to a server later in case of no internet situation. Is PBKDF (password) should be a good ...
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What encryption shoud I use for single char encryption?

I'm very new to encryption and I wanted to know if it is secure or just possible to use encryption on single chars. I did some research, but nothing to clear and i'm a bit confused. The modes I think ...
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Can the original data be extracted from an RSA private key signed message

I'm working on a system that the main objective is to verify the message was written by the right person, but it would also be desirable if the message can't be understood by anyone sniffing it. It ...
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Prime number size and RSA decryption

Is there a former proof for why larger prime numbers make RSA securer? Maybe a theorem to show that it takes much more time to find out the private key if primes are larger?
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I am participating on an international competition, my topic is Cryptography: The RSA Algorithm [closed]

I am participating on an international video science competition. My topic is Cryptography: The RSA Algorithm. I would be more than happy to receive your feedback! Please take a look at it! It will ...
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RSA - What's to stop someone from using the same ciphertext to mimic private key holder?

I've recently looked into fundamentals of RSA and think I understand how it works. However, there's one basic problem I can't seem to figure out. If someone received ciphertext for a given message, ...
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CRT to decrypt RSA [closed]

How can the Chinese Remainder Theorem be used to decrypt RSA (or the public key) and find out the private key? If it is possible to do this with the CRT, then does the size of prime numbers used to ...
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What does it imply if in RSA pow(m, e, n) is same as the m

So, Let's assume we have n which is made up of 2 strong primes which cannot be factored & e which is textbook value of e ...
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RSA Digital Signature System is failing for larger Prime numbers [migrated]

I implemented RSA cryptosystem to create a simple digital signature system. It is for freeCodeCamp's upcoming Cryptography curriculum. The below program logs "Failure" when I use some bigger prime ...
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Why is prime number size important for RSA security?

RSA modulus is $N = pq$ where $p$ and $q$ are prime numbers. I read from somewhere that the time it takes to decrypt the RSA encryption increases exponentially as key length increases, which depends ...
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RSA factorization with special primes

Suppose that primes for RSA modulus are generated using formula: $P_i(x,y) = \operatorname{next\_prime}(x^{z_i}+y^{z_i}) = x^{z_i}+y^{z_i}+d_i$ where $x,y$ are unknown random numbers with size 128 ...
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Probabilistic verification of signature schemes like RSA?

I was wondering if there were any verification algorithm in the literature that enables a "probabilistic" verification of well-known signature schemes? For RSA signature verification for example, is ...
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I have created values for RSA encryption but it doesn't always work [duplicate]

I am using the values as follows: $(p, q, n, \phi(n), e, d) = (1033, 5039, 5205287, 5199216, 65537, 3784241)$ Yes, I have made sure $e$ and $\phi(n)$ are coprime. For example, if I were to encrypt ...