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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How to generate a bilinear group of prime order p [duplicate]

I am trying to implement an IEEE Paper In Cryptography. I read many reference regarding an RSA key generation. But i am confused with above statement. Please someone explain me What it says with ...
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263 views

Signing/verification between Java and the OpenSSL

I'm trying to sign/verify data between a C application and a Java application. In java for now I was using the built-in JCE provider with SHA256withRSA as ...
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1answer
233 views

How long does it take to decrypt an RSA/ECB encrypted message?

I am working on assignment where I have specific scenarios and I am little bit struggling with this one. Alice sends and email to Bob.For this e-mail, she uses the following method of encryption: ...
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1answer
98 views

How to compare the efficiency of public key cryptosystems, i.e., RSA vs El Gamal?

As part of my Mathematics degree I'm taking a Discrete Mathematics module which partially covers Public Key Cryptography but does not at all enter it in depth. I'm currently working on a project that ...
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1answer
44 views

What part of an RSA key is referred to by the number of bits? [duplicate]

When we speak about 4096- or 2048-bit RSA keys, what part of the key is this number of bits? The public key comprises both the modulus and the public exponent, and the strength of the key can also be ...
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92 views

Securely generating auth tokens

(Disclaimer: I'm an experienced server-side Java programmer, but with little crypto experience.) Objective: I've got a login server which, given a login+password pair, should issue a unique auth ...
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151 views

Cracking simple RSA when just the ciphertext and one public key is known

Can someone explain to me (Or better yet, point me to a tool that does the brute forcing) how to crack a standard, simple RSA cipher (So don't bother with padding) if I know just one public key, the ...
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1answer
147 views

Symmetric encryption using RSA for random generated password

I'm fairly new to encryption, so I wanted to check the logic for a .net solution I'm working on that encrypts data between two parties. the receiving (decrypting) party will have an RSA key pair ...
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111 views

Leading 00 in RSA public/private key file

I found these following values ALWAYS have the leading 00 in public/private key, public key: modulus private key: modulus, p,q, d mod (p-1), d mod (q-1), coefficient e.g., modulus ...
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Strength of a cryptography algorithm [duplicate]

I'm just read this article from Atmel corporation in comparing RSA with ECC cryptography algorithms. First of all please read these two paragraphs quoted from the article: P1: Strength of an ...
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173 views

Consequence of a change on the Guillou-Quisquater Protocol

In the Guillou-Quisquater Protocol, the prover convinces the verifier that he knows an $e$-th root of an element $y \in \mathbb{Z}^*_n$ ($p, q, e$ are primes, $n = pq$ and $e$ is coprime with ...
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3answers
156 views

Factorizing N to derive D [duplicate]

So I have the value of N. I have to use this value of N to find the value of D. N = 265291078722948385089717069136983657793 Now I read about RSA algos and found out that ...
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126 views

Relationship between exponent and modulus in RSA (as RSA properties as listed in X.509)

In one of my assignments, I had the following question (Please read on. Not a homework assignment :) ): X.509 (1998 version) lists properties that RSA keys must satisfy to be secure. One such ...
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62 views

Calculating Phi(M) and D for RSA decryption given p,q,e

I've been given a message in 4 digit numbers but it doesn't seem to work when I use my calculated values for phi(m) and d. If I'm correct phi(m) = (p-1)(q-1) correct? And d is given by ed = ...
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1answer
207 views

RSA vs ECDSA/ECDH

So we've been using RSA for a while now. I wonder, is it still secure? I'm wondering whether surveillance agencies can at this point read traffic encrypted with say, TLS_ECDH_RSA_WITH_AES_128_GCM? ...
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106 views

Why is RSA encryption version 1.0 not specified in an RFC?

I saw that there are three RSA encryption versions, as follows: RSA encryption version 1.5 (RFC 2313) RSA cryptography specification version 2.0 (RFC 2347) RSA cryptography specification version 2.1 ...
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72 views

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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1answer
78 views

Diffie-Hellman using a different modulus on both sides

For Diffie-Hellman Key Exchange, the used modulus is the same throughout the process. Is it possible to use 2 different for both sides? For example, $A \gets M^{d_1} \pmod{n_1} $ $B\gets M^{d_2} ...
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Is using same key pair for both encryption and signing secure in RSA [duplicate]

In GPG, we can use same key pair for encryption and signing. Can't/Shouldn't we do this in RSA. I am using RSAES-OAEP and RSASSA-PSS, not raw RSA btw.
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How to decrypt RSA cipher text? [closed]

How can I decrypt an RSA cipher text in which I am only provided with a public key and the cipher text. The person who encrypted it made a mistake in taking the exponent.
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1answer
201 views

RSA time function

I am doing a paper on textbook RSA (highschool-level). I am explaining and proving the significance of the public key exponent in time and security. So far, I have encrypted a constant message with a ...
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66 views

PublicKey Unknown Encoding

I have a public key: ...
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140 views

Is it possible to correct the exponent of an RSA public key if it has been altered?

Is it possible to change the exponent of an RSA public key?
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Usefulness of ability to calculate $m^{p+q}$ with RSA

I noticed that with only an RSA public key, it is possible/tractable to calculate $m^{p+q} \pmod n$ for any $m$ without knowing $p$ or $q$. Namely, $m^{p+q} \equiv m^{n+1} \pmod n$. (This follows ...
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Is it possible to recover an RSA modulus from its signatures?

Let's say that you have some small number of RSA signatures of known data: you know some pairs $(m_k, c_k)$ such that ${c_k}^e \equiv m_k \pmod n$. If you know $e$, because probably it's one of $\{3, ...
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125 views

Possible to guess RSA public key $e$ using $n$ and $\phi$

We know that if $n$ and $\phi$ is known, then it is possible to find $p$ and $q$ (initial prime numbers). I have following the questions: Assume the public key $e$ is not known, how difficult would ...
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215 views

Can e = 2 be used in unpadded RSA?

I am wondering whether $e = 2$ can be used in unpadded RSA... It seems like it is not possible to use it: the value of e needs to be coprime with $tot(n)$. $tot(n) = (p - 1)(q - 1)$ where $p$ and $q$ ...
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115 views

Encrypt letters separately?

I am trying to encrypt the word Hello using RSA. When encrypting Hello’s integer representation, is each letter encrypted ...
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258 views

Large primes p and q for RSA

I am writing a high-school paper on textbook RSA (the mathematical aspect only). Many definitions of the RSA method start off with saying that one should: Generate two large random (and distinct) ...
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3answers
722 views

Is it possible to reduce the size of an RSA key?

The details about what an RSA key is made up of are explained succinctly here. Is it possible to reduce the amount of data that's usually packaged with the (private) key and then derive it later?
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134 views

How to convert RSA public keys to one key to use for text hashing?

I've recently asked a question about RSA encryption. One of the things that I don't understand is the usage of two public keys. In the example on Wikipedia, a message is encrypted like: ...
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2answers
104 views

How do you communicate the hash function used with RSA signing?

When it comes to RSA signing, I understand why you need to hash the data before signing it, but don't you need to communicate what hash algorithm you use to whoever will need to verify the signature? ...
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52 views

What is the most an adversary can do in the context of public key masquerading?

Suppose two parties A and B are using a public-key encryption scheme in order to communicate securely. A and B both have a public/private key pair: $$ A: (P_A, S_A), B: (P_B, S_B)$$ and A already ...
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226 views

RSA reconstructing private key knowing MSBs

PREMISE: This question is purely theoretical because usually an attacker will not know private exponent d and can't compare it with obtained MSB bytes. Suppose an RSA 1024 bit signature. An attacker ...
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248 views

File encryption using per-user-encrypted shared key

So I'm looking to encrypt files using AES CTR, using a shared key which would be accessed via a per-user password. My two main concerns are: - making sure that the algorithms in use are appropriate ...
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Fingerprint RSA public key in PKCS1 format

I can't find anywhere details on how to fingerprint a public RSA key in PKCS1 format. There are a lot of examples on the internet on how to fingerprint an RSA public key in openssh format using ...
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Understanding RSA [duplicate]

I'm reading RSA in Cryptography Course. There is portion of RSA that's confusing me. In Handbook of Applied Cryptography its written Represent the message $M$ as ...
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232 views

Encrypt large data with RSA through blocks in java

I'm working on a communication protocol where a client sends encrypted data to a server. What happens is that in some point, the client creates a symmetric key used to create data digests through the ...
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104 views

Values of p and q when e = 3 (RSA)?

I am doing a paper on textbook RSA (this is for high school btw) and in my example I need two very large primes, but I want my $e = 3$. Is there a short way to calculate the values of $p$ and $q$ ...
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241 views

RSA Signature Verification Implementation on Cortex M0

I have to implement RSA Signature Verification procedure (RSA-2048) on a Cortex M0 based MCU. My budget is 15kB Flash and 2-4kB Flash RAM. Is it even possible to do RSA on a low end MCU based on ...
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public/private key: is it possible to have master public/private key

This may be a very primitive question which might not be possible but I have this question to understand. Assume Yahoo provides a messenger where yahoo users can chat in secure way (end-end ...
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1answer
237 views

ECDH or RSA more secure for symmetric key wrapping?

Suppose a message is encrypted with a symmetric block cipher with a random key. RSA is often used to wrap the symmetric key using the recipient's public key. In this case, the size of the message is ...
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393 views

Can an ephemeral RSA key give forward secrecy?

Suppose party A generates an ephemeral RSA key and sends the public key to B. Party B then generates a symmetric key, encrypts it with Party A's public key and sends the Ciphertext to Party A. Party ...
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2answers
112 views

Inverting RSA function

I am in high school and I am writing a paper on RSA. I want to show that low values of the public key exponent can make it easy to 'invert' the function so that the encrypted message can be recovered. ...
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1answer
138 views

Wanted: Simple ring signature example

I spent all day trying to figure ring signature schemes out but apparently I wasted time. I read the original ring signature paper (Rivest's How to leak a secret). I'm having numerous problems. Let's ...
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448 views

How does RSA compute such enormous numbers?

So I have been reading and learning a lot about cryptography lately and in particular asymmetric ciphers such as RSA. One thing that I am curious about but never seems to be mentioned is how the ...
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1answer
169 views

RSA 1024 bit forge a new matching signature from a chosen message

I have an RSA signature scheme with 1024-bit key where I know the following: Public modulus $N$ Public exponent $e=3$ A lot of signatures Summary: To compute a signature, an MD5 hash is ...
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237 views

lcm versus phi in RSA

In textbook RSA, the Euler $\varphi$ function $$\varphi(pq) := (p-1)(q-1)$$ is used to define the private exponent $d$. On the other hand, real-world cryptographic specifications require the ...
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How is RSA able to prevent brute forcing using the public key?

Bob calculates a private and public key. Bob sends his public key to John. Jeff is a third party unwanted member and manages to snatch the public key mid-transfer. John encrypts his message ...
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Is it possbile to get same set of public and private keys twice while creating CSR ? If so where does the conflict happens !?

I'm new to cryptography and please clarify if my below assumption is wrong. Lets assume, that two different banks creating CSR and they get identical public and private key pairs of RSA. In such ...