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.

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Cube-Root attack - RSA with low exponent

I have this RSA public key ...
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How to generate 1024-bit RSA key

I have generated a prime number with a 1024-bit size. Now, when I create an RSA key - how many bits does the key have?
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Equivalent RSA modulus for NIST P-192 and P-521 elliptic curves [duplicate]

At www.keylength.com, I found the following table of ECC field size and the corresponding RSA modulus recommended by NIST. ECC Modulus RSA Prime Size 160 1024 224 2048 ...
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RSA: Why must e be relative prime to phi(n) [duplicate]

I've got a question concerning fields used in RSA. Let's use the following symbols for my example: {p,q} = primes {e,n} = public key {d,n] = private key I learnt that an inverse element exists if a ...
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Random unique key per message, safe to use key as IV?

The overall setup is that I am using RSA public key encryption, and because the messages are big instead of encrypting the entire message via RSA I am encrypting a random AES-128 key with the PK and ...
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How can a decryption program tell me that a private key is incorrect for RSA and ECC?

I have a program which will encrypt the symmetric key with RSA public key with keysize 2048. I am able to decrypt the message with the corresponding private key. My question is, is it possible to ...
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Euler's totient function and Carmichael's totient function in RSA [duplicate]

I'm a high school student taking IB and I'm doing my EE on Maths, more specifically on the effectiveness of Euler's totient function and Carmichael's totient function in RSA. Am I right in thinking ...
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RSA Attack, known public key and ciphertext. Can decrypt the message m?

I'm stuck with this problem: Assume Alice and Bob are using RSA to communicate each other. Given Bob's public key $(217,7)$, Alice send the ciphertext $c=53$ to Bob through RSA encryption. Now, Eve ...
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976 views

When is public-key crypto used / when is symmetric crypto used?

I read in the book "Cryptography & Network Security" that it has almost been universally accepted that public-key cryptography is restricted to only being used for key management (Does this mean ...
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One-time pad using RSA and Diffie-Hellman functions

Suppose that Alice and Bob use an encryption algorithm based on a one-way function $F$ (Eve knows it), and $r$, a secret key shared between Alice and Bob (Eve doesn't know it). Key is computed as: $K =...
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When was a RSA Private Key Introduced?

I'm doing some research into the RSA cryptosystem but I just need some clarity on how it worked when it was published in the 70s. Now I know that it works with public keys but did it also work with ...
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RSA: How effective is this keypair-trash attack [duplicate]

A question that could very well be part of xkcd's "what if?": Let's say Monica made a piece of software that sends all RSA keypairs to a central database after they're not used anymore. Something ...
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How to cipher bocks with RSA in ECB mode?

I'm trying to implement a very basic RSA with functions that should generate RSA keys and cipher some text. GenKey function returns a tuple ...
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Finding the prime factors of $n'$ given the previous $n$ and its prime factors $p$ and $q$

Say I have a very large number $n$ = $pq$ where $p$ and $q$ are prime. A new number $n'$ is generated by increasing these prime factors. How can I find this new number's prime factors?
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Find private exponent in RSA [duplicate]

The other answers for this confuse me, I know the principle of d in terms of the equation it has to satisfy. However I'm not sure how I would go about finding the private exponent without trial and ...
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Will publishing two or more public keys of the same RSA private key cause a security risk?

I want to make an end-to-end messaging platform where everyone is identified with a unique random private key. Everyone uses other peers' public keys to identify and send encrypted messages and verify ...
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Confused about final subtraction of modulus in Montgomery Multiplication, during modular exponentiation

I'm confused about how one might supposedly bypass the final subtraction of the modulus in radix-2 montgomery modular multiplication, when used in a modular exponentiation algorithm. The following two ...
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Computing the cardinality of the co-domain of specific modular exponentiations

Consider the following function: $f: \mathbb{Z}_n \rightarrow Y,~x \mapsto x^e \bmod n$, where $n = p \cdot q$ is an RSA modulus and $\gcd(\varphi(n),e) \neq 1$ (contrary to what's required for a ...
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Padding RSA with random number

I known the post from here and here regarding RSA padding. I still don't understand why simple addition of the message with an random number and then encrypting the result with plain RSA isn't secure. ...
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Cryptographic methods that do not use prime numbers?

Does anyone know any cryptographic methods that do not use prime numbers? If so, which ones?
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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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Is it possible to generate an RSA SHA1 signature only from a public key?

Is it possible to generate signature only from Public key. See example below where i have valid signature but what if I change hash ? Is then any way to do this? Public key(160 bytes): ...