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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Can I get successful signature verification with just altering message and signature?

Assuming I can modify a message and also modify the verification signature, and I also have the public-key but not the private-key. Can I create a message that can be verified with a signature that I ...
2
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1answer
211 views

RSA signatures without padding

Suppose I have a message $M$ for which I generate an RSA-2048 digital signature as follows: $H = H(M)$, $H(M)$ being the SHA-256 of the message $M$ $S = H^d \bmod N$ Assume $N = pq$ is properly ...
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2answers
5k views

Why can’t DSA be used for encryption?

This question at StackOverflow mentions that DSA cannot be used for encrypt. But Both RSA and DSA can be used to generate public and private keys, right? (Or am I wrong?). Then why can't I use the ...
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1answer
41 views

Where is the mistake in my RSA by-hand calculation?

Like several previous askers, I seem to have made a mistake in my RSA calculation, but despite going back over it three times, I cannot spot it. I picked 1000003 and 6000011 as my primes, ...
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0answers
14 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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70 views

Algorithm for Boneh and Durfee attack on RSA

I am trying to understand various attacks on RSA and I believe that they only way to fully understand the algorithm is to implement it. I am trying to implement the code in this paper (Private Key $d$ ...
3
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1answer
73 views

What is the private key in RSA?

I'm new to cryptography and I have a doubt: I read some pages a bit different definition for the RSA private key: In 1 - (n, d) In 2 - ...
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2answers
1k views

RSA encryption using multiplication

Generally in RSA we encrypt as $m^e \pmod n$. Will RSA work if we replace the power by normal multiplication? $E = (m \times e) \mod n$ and decryption as $c \times d \mod n$. What will be $d$ ...
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3answers
764 views

How can mega store my login details and still be secure?

I understand how Mega's encryption works. For a quick summary of all those in the future looking for an answer on this... here is how it works: Upon first signing up for an account you make a ...
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1answer
77 views

Why is padded RSA not CCA-secure?

Why is the padded RSA construction given in the picture not CCA secure?
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2answers
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Why is PuTTYgen-created RSA public exponent(e) not in {3,17,65537}?

As far as I know, RSA public exponent(e) should be one of {3,17,65537}. However, I found PuTTYgen-created RSA public exponent(e) is 0x25(37) by default,as follows, (PuTTYgen version: 0.66) I am ...
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1answer
49 views

Trying to udnerstand textbook sample solution

I am preparing for the final exam in my Data Security class so I am trying to read and understand the textbook's exercise questions. The sample solution at the end the textbook is more like a hint ...
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1answer
229 views

Help with RSA-2048 crypto ransom virus [closed]

The RSA-2048 Crypto Ransom Virus has devastated me, I tried the backup method, the previous version, the Shadow Explorer, it deleted all my restore points, Its took out 5 HDs and my USB pen that ...
45
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1answer
3k views

Why does my SSH private key still work after changing some bytes in the file?

I (for a test) just randomly altered a private RSA key by opening it up in Vim and changing a few bytes. It is the private part of an SSH key pair used for logging in on a remote system. Puzzlingly, ...
0
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0answers
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 ...
3
votes
1answer
211 views

Why not use OAEP for signatures?

There seems to be a distinct lack of implementations of RSA signatures using OAEP to pad the digest. Other than the old, funky, padding schemes, it's PSS all the way. PSS seems to have the whiff of ...
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4answers
835 views

Why is public key cryptography (RSA) used in sites like Google or Facebook?

The RSA algorithm is used for encryption (plain text to cipher text) and decryption (cipher text to plain text) of data. What is the need for using public keys in these sites; why is data is encrypted ...
4
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1answer
100 views

Distribution based integer factorization

The past week I've been looking into - and playing with - algorithms for factoring RSA moduli. From what I understand, it's important that the primes p and q are of the same magnitude as the square ...
39
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6answers
195 views

How to check that you got the right key when brute forcing an encryption?

How do you know when you have the right key when brute-forcing? Let's say that they test the right key. They then have to check that the decrypted text makes sense. To do so, they can test whether ...
4
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1answer
163 views

How to generate a bilinear group of prime order p for key generation

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 ...
0
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1answer
59 views

RSA-OAEP: How does it work?

I was looking at this image about OAEP: ..and was wondering what was happening here. We have a data block DB which consists of: ...
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0answers
31 views

How to use OpenSSL command line utility to encrypt data with encrypted key from public key?

I may not be asking the right question. I am fairly new to data encryption. I am currently being sent encrypted data that's stored as follows: [ [keysize] [key encrypted with public key] [ivsize] ...
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3answers
107 views

with RSA encryption, how do I find the md5sum of the private key from the public key?

This is a purely mathematical question on RSA encryption. Having $e$ as the public key exponent and $n$ the modulus of a public key. Can I recover the md5sum of the private key $d$ (inverse of $d$ ...
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1answer
146 views

In RSA. Why is $\phi(n)$ kept secret and $n$ is public?

I mean, $n$ can also be easily used to find the factors $p$ and $q$ right?
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0answers
10 views

Using Openssl Libarary to convert .key encoded to .pem [migrated]

So i created a c program that takes in an encrypted (encrypted.key) file and a public key to decrypt the private encrypted encrypted.key. However, my program only works when taking in two files that ...
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1answer
80 views

RSA when n= 2360221 and encryption = 5 find decryption key d, when M =1234

when n= 2360221 and encryption = 5 find decryption key d,and Cipher text C when M =1234
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2answers
187 views

Trapdoor and RSA (Schneier)

Disclaimer: I'm new to cryptography. Background: From Applied Cryptography (Bruce Schneier), page 30 of 2nd edition A trapdoor one-way function is a special type of one-way function, one with a ...
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2answers
155 views

Modular Multiplicative Inverse and RSA?

In trying to understand this specific part of the RSA algorithm, I found this online: $$e \cdot d = 1 \pmod{(p-1)\cdot(q-1)}$$ Therefore: $$e \cdot d \cdot d^{-1}= d^{-1} \cdot 1 ...
3
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1answer
83 views

Trying to understand textbook exercise question regrading RSA

I am preparing for the final exam in my Data Security class so I am trying to read and understand the textbook's exercise questions. Any hint would be great. Question (Exercise 9.14 of textbook): ...
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0answers
28 views

How to vary bit length of prime numbers in RSA by using MATLAB? [closed]

Please Can any one Tell me how to vary bit length of prime numbers of RSA cryptography algorithm in MATLAB.When i am considering more then 16 bit length of prime numbers Its not working. So can any ...
1
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1answer
65 views

SHA256(RsaPrivateKey) == AES key?

I have an RSA private key (more specifically, an SSH key in Putty format, 4096bit) and want to use its SHA256 hash as an AES256 key, instead of using an independent newly generated AES key. Are ...
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votes
0answers
31 views

Encrypt file using pycrypto RSA from python [closed]

Basically I am writing a program that needs to have basic encryption for storing some program parameters in a config file. The program is run under linux debian. Since sudoers can modify the config ...
2
votes
1answer
456 views

The Boneh-DeMillo-Lipton fault attack (RSA CRT)

I am trying to understand the Boneh-DeMillo-Lipton fault attack on RSA CRT signature. Suppose that we sign a message $m$ with RSA-CRT : $d_p = d \bmod (p-1)$ and $d_q = d \bmod (q-1)$ $s_p = ...
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0answers
22 views

Are the prime numbers used for RSA encryption known? [duplicate]

I read that one reason why RSA is secure is because it uses a huge number that's called the modulus which is the product of two prime numbers. For maths reasons the prime numbers being prime numbers ...
2
votes
1answer
206 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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0answers
45 views

Meaning of “random n/2 bit prime length prime p”

iam trying to solve a homework for the subject "system security" at university. For my question iam referring to this document: Solution to the Millionaire's Problem Could you please tell me why in ...
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2answers
48 views

Stripping off message authentication or signature

If attackers can strip off RSA / EC / -DSA digital signature and conduct CCA on AES-CTR or CBC payload, why can't they do the same for AES-GCM?
5
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1answer
61 views

Can RSA-PSS signing be made deterministic without loss of security?

Is it possible to make RSA-PSS signing deterministic without loss of security? Specifically, I would use Blake2b of the key and message to generate the salt.
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2answers
25 views

Is ssl_sign safe as it is using OPENSSL_PKCS1_PADDING

I've been hearing a lot of scare talk about PKCS1 padding attacks. Is PKCS1 v1.5 safe in signatures as it is practically transporting only message digest? I'm using it in one of my applications so ...
0
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0answers
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 ...
0
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1answer
71 views

Inverting RSA using an oracle

Say you are given an efficient deterministic algorithm 'I' that can invert the RSA function on 1% of the points in $Z^*_{N}$. That is to say that if y $ \in $ $Z^*_{N}$ is a "good" point for 'I', ...
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3answers
2k views

Is there any more information on this RSA backdoor?

Someone posted this on reddit a few days ago, and I haven't found much about it except for links back to the same page. Here's the article ...
3
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1answer
71 views

Schnorr signature security level as compared to AES/RSA

As per the Schnorr's original paper (1991), The Security Complexity $2^t$: We wish to choose the parameters $p$, $q$ so that forging a signature or an authentication requires about $2^t$ steps by ...
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1answer
51 views

Comparison of RSA and DRSA scheme using SageMath

I am trying to compare the encryption and decryption speed of the RSA and the DRSA scheme with same public key $(n, e)$ and private key $d$ (using SageMath). For $1024$ bits long $n$, I got the ...
3
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1answer
97 views

Space needed to store an RSA private key

How much space is actually needed to store a $4096$-bit RSA private key? I originally assumed $0.512$ kB since $\frac{4096}{8} = 512$, but then I started to wonder whether it was in hex. Simply, ...
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0answers
34 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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1answer
98 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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1answer
85 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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20 views

Should we use exponent 3 in RSA-OAEP?

As I understand it the proof that RSA-OAEP is secure in the random oracle model is much tighter for exponent 3. Does that mean that exponent 3 should be chosen?
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1answer
73 views

Clifford Cocks Interview: “Raising numbers to a power with the product as modulus”

Disclaimer: I'm new to cryptography Background: Clifford Cocks, the former GCHQ mathemetician and crytologist, gave an interview where he said: "My thinking was that you need something that is ...