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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Why is RSA still being used? [duplicate]

In hybrid encrytion, I still see that some site's use RSA in their https connection, so now I wonder, why do they not use ECC instead of RSA, ECC requires less computational power and encrypt's and ...
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21 views

Diffie-Hellman combined with DSA/RSA

we have learned Diffie-Hellman, RSA and DSA (Digital Signature Algorithm) in university. Because DH is vulnerable of Man-in-the-Middle we had the task to program the DH combined with RSA to protect ...
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44 views

How to encrypt huge data using RSA? [duplicate]

Is there any way to encrypt the huge amount of data using RSA? I was supposed it is possible but when I read some articles what I saw is that, this is bad practice or they say can only encrypt bit ...
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70 views

RSA PlainText without Knowing Private Key

I couldn't solve this problem for three days... In RSA, [n = 13, 19] [e = 3] c1 = m^3 = 83 mod 247 [e=5] c2 = m^5 = 97 mod 247 then, use ...
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46 views

What is proper size of window Using RSA Window method?

I want to Use Window method for RSA modular Exponentiation. because of SCA. But I don`t know what is proper window size.
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64 views

How to decrypt an RSA ciphertext given an oracle providing the lower 8 bits of decryptions?

I have access to an oracle that can encrypt and partially decrypt a number with RSA-1024 algorithm. For encryption: \begin{equation} C = M^e\bmod n \end{equation} But for decryption, result will ...
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21 views

Securely register a client in server using AES an RSA

I've designed the following protocol to send the client's public key to the server. Initially, the client knows server's public key, but the server does not know the client's public key. client ...
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47 views

How to use the hardcoded server's public key to register a client application?

I'm designing the security for a smartphone app that can be used to make car reservations. Clients have to register them with their driver's licence through the application and can then book a car. ...
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17 views

Is AES-256 bit encryption secure against this kind of attack? [duplicate]

Recently I came across this article. http://www.cs.tau.ac.il/~tromer/acoustic/ Could this put all computers at risk for decryption?
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27 views

Weaknesses of RSA for $e_A\neq e_B: \gcd(e_A,e_B)=1$ [duplicate]

If two people, A and B, are using a common RSA modulus N, and they select distinct exponents $e_A$ and $e_B$, such that they are coprime, why does this mean that someone can decrypt (in polynomial ...
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38 views

How common are non-RSA digital certificates?

Is there a statistic available that shows just how common are DSA or ECC certificates amongst webservers? I know that RSA-based certificates are the most common, however I'd like to know, if there is ...
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127 views

RSA encryption with private key, decryption with public key (again)

First of all let me point out that I am aware of all the theory behind asymmetric encryption and signing, and other related areas like signcryption, etc. It seems that mathematically it is possible to ...
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101 views

Large Volumes of Asymmetric Encryption

First of all, I apologize in advance if I use any incorrect terminology. I am just getting my feet wet when it comes to cryptography and there is a lot to learn. For the past 12 months we have been ...
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57 views

Encoding issue - PKCS#11 CKM_RSA_PKCS wrapping unwrapping EME-PKCS1-v1_5

I am trying to figure out why I am not able to get compatible format of EME-PKCS1-v1_5 3DES key encrypted by public RSA key. I need to send to a third party 3DES key encrypted using their public RSA ...
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50 views

Proper forward secrecy [closed]

Currently I have a protocol using a simple RSA to AES handshake. I have been reading more and more and would like to implement proper forward secrecy, but at the same time I'd like to improve the ...
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24 views

Is RSA safe anymore? [duplicate]

Some people may have heard of Shor's algorithm. It allows for integer factorization on a quantum computer. This wasn't a problem a little while ago since we didn't have any quantum computers. Google ...
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61 views

RSA : Double-Encryption and order of Encryption

I'm studying cryptography and we're looking at RSA. We're required to do a double encryption from Alice to Bob and then Bob back to Alice. We've been told the order of encryption is important and it ...
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122 views

Complexity using RSA

You encrypt a message using the RSA encryption system as $t^e \pmod n$ , where $t, e < n$ and $t$ is the numerical equivalent of the message. The message is written in a $27$-letter alphabet and is ...
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103 views

splitting the plaintext and ciphertext into blocks

Say I was to use RSA with a given value of n. I choose to split the plaintext and ciphertext written in a 27 letter alphabet into blocks with k and m characters resp. How would I find the largest ...
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23 views

How to calculate Private Key in RSA using Extended Euclidean Algorithm [duplicate]

I have googled for about 2 hours now and still haven't found an explanation. The wiki article just makes me more confused and so has every other similar question I've found on StackExchange. Here's an ...
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16 views

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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17 views

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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79 views

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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256 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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29 views

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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105 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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87 views

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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In the RSA encryption system, are there not multiple messages m that give the same cipher text c? [duplicate]

For example: p = 5, q = 11, n = 55 $\phi$(55) = 40 e = 3, $\phi$(55) and 3 are relatively prime m = 3, then: $3^3 mod(55) = 27$ m = 113, then: $113^3 mod(55) = 27$ I heard that e and $\phi$(n) ...
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45 views

RSA Encryption: What happens if n is a factor of the message M? [duplicate]

From what I have learned about RSA encryption, the message M and the modulo n must be coprime because Euler's theorem only holds for coprime numbers? for example, what happens if I choose p = 3, q = ...
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138 views

RSA-PSS salt size in certificate

In RFC 4055, the signature RSAPSS algorithm has the following ASN 1 parameters: ...
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1answer
17 views

PK systems using groups in practice

The four Public-key cryptosystems: RSA, ElGamel, DH, and Rabin (all with others) all require some group operations in an integer field or multiplication group of some residue classes. When it comes ...
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20 views

RSA: If I sign the same digest with same key twice, will the signatures be identical? [duplicate]

If I don't have public keys to verify the signature, can I use this to discover that two signing services are using the same key? Can you send a reference?
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87 views

What is the danger if a non-prime is chosen for RSA? [duplicate]

I was reading this question about generating primes for RSA keys. The answers point out that most implementations of of the algorithm use probabilistic prime-ness checking algorithms. The answer by @...
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124 views

Euler's Totient function for semiprime numbers

I have noticed, during the period I spent studying RSA, that Euler's Totient function can be calculated in another way than $ϕ(N) =(p-1).(q-1)$ Let me explain myself by pointing to a brief example: $...
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2answers
311 views

How to decrypt a PGP message with only the two primes and the public exponent?

I'm trying to decrypt a PGP Message that is encrypted with an RSA key, but I only have this information: Public exponent: 65537 Prime 1: ...
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42 views

trying to get calculator and RSA calculatin does not make sense [duplicate]

got two question, I am novice in the area of crypto and currently in big learning curve. From crypto book I am going over with, I see the RSA algorithm example as follows: it chose two rand #-s: p=...
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1k views

Decrypted RSA 64 bit encryption using modulus and private exponent. Got gobbledygook [Verify] [closed]

As part of an experiment, I was given a .enc RSA (encrypted) file that was most likely generated using openssl. I had the public key, I factored it, obtained the private exponent, and decrypted the ....
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2answers
194 views

Assemble RSA keys from components [closed]

I'm studying openpgp cryptography and struggling to understand some things. I can't use pgp tool for generating keys and ecryption, but have to write a simple app to generate keys, encrypt and decrypt ...
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42 views

RSA: If I know n, e, p, and q, how do I calculate d using the extended euclidean algorithm? [duplicate]

After doing a good amount of research, it's become fairly obvious that I ought to be using the extended Euclidean algorithm to calculate d from the data that I already have. However, this isn't an ...
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33 views

Practical strength of non-2^n RSA key lengths [duplicate]

It has for many years been popular to use RSA keys that have lengths that are powers of two. E.g. 1024-bit, 2048-bit and 4096-bit key lengths are all popular for use with OpenPGP implementations such ...
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68 views

Requested to encrypt data with AES256, digital certification, timestamped

at my job we have been tasked by gov to encrypt some data we send to them. The "law" says we have to do the title above, but they only need us to do the AES256 thing because the data is not really ...
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161 views

Fault encryption attack on RSA [duplicate]

How to recover plaintext, if we know public key(RSA), correctly encrypted text and text encrypted with faulty public key, where one bit is changed?
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76 views

Crack RSA with additional information [duplicate]

Suppose $N=3953$, Alice encryption key is $e_A = 337$ and bobs is $e_B=23$. Eve happens to know the corresponding decryption keys, $d_A=3385$ and $d_B=2663$. Can I use this information to find the ...
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172 views

Two questions on EMSA-PKCS1-v1_5

If I implement EMSA-PKCS1-v1_5 in the following two non-standard ways, what kind of things could go wrong? The padding structure will be referred as (00|01|PS|00|DER(Digest Algo)|Digest), where | is ...
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29 views

How to find the factors of the modulus? [duplicate]

In the article "A Method for Obtaining Digital Signatures and Public-Key Cryptosystems", the original RSA article, it is mentioned that Miller has shown that n (the modulus) can be factored using any ...
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280 views

RSA - Why should we sign hash rather than raw content? [duplicate]

Apart from obvious performance considerations, is there any mathematical or crypto reasons that imply that we sign a hash rather than a raw content ? I read that it was because the hash must fit in ...
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129 views

Possible to know who is the owner of a message encrypted with RSA public key

Given the scenario in which I want to send 10 messages either to Stalio or Olio. I encrypt these messages with their respective public keys using textbook RSA, before sending the messages to their ...
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97 views

Probability of factoring keys as a function of bit length [duplicate]

kinda new here, I had a question pertaining to someone being able to factor one's RSA keys through the GCD. Anyways the question goes that there are two people: A and B. A makes his/her private key as ...
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88 views

Low exponent attack against RSA

According to this: http://www.cims.nyu.edu/~regev/teaching/lattices_fall_2004/ln/rsa.pdf One can calculate the message m, if there was no padding scheme involved. My question: is it possible to find ...
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105 views

Montgomery Multiplication in FPGA explanation

I'm trying to implement an RSA module in a FPGA. I choose to use Montgomery multiplication. I've found a document where the Montgomery Multiplication is pretty clear. I don't understand only a step. ...