RSA is a common public key algorithm, which can be used for encryption and signature. It is a core component of most the security protocols used on the Internet, including the SSL/TLS protocol suite.

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Which host key algorithm is best to use for SSH?

When you first connect to an SSH server that is not contained inside your known_hosts file your SSH client displays the fingerprint of the public key that the server gave. I found from this question ...
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2answers
108 views

Encryption - RSA vs. AES

I have a question regarding encryption and whether to use symmetric or asymmetric encryption. The idea is to implement a form of data encryption in a variety of software. This data will be exchanged ...
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0answers
39 views

AES256 key exchange

I'm trying to get a secure way of exchanging keys between my client application and the server. The goal is to encrypt all XML messages with AES256. These XML's will be transferred to the server ...
3
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1answer
63 views

Securing a private RSA key for distribution

There's a new law concerning POS systems in Norway which comes into effect 1.1.2017 starting that: b. Private Key – is secured by the system vendor, only the vendor knows the key. c. Public Key –...
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1answer
24 views

Why are there leading 0x00 bytes in the subjectPublicKey field of a DER X.509 cert?

For a simple example, I'm using a 512-bit RSA cert to illustrate my question. The cert can be found in both DER and PEM form here. I've been going through the certificate using this ASN.1 decoder (the ...
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27 views

TLS 1.2 ECDHE_RSA signature [migrated]

I'm currently working on a Java TLS server. I'm trying to get the following CipherSuite to work : TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA When I test it using openssl s_client I get the following error ...
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1answer
43 views

RSA Decryption Problem equivalence [closed]

My question is: what problem is the RSA decryption equivalent with? factorization Euler-phi function calculation Rabin decryption RSA key calculation
3
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1answer
134 views

The NSA circumvents encryption and how would I protect myself from these type of attacks? [closed]

For the sake of this question, assume that I am security conscious to the point of paranoid. I am concerned that older versions of GnuPG may be compromised due to RSA encryption keys because of known ...
3
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1answer
79 views

Recommended Crypto Security Setup (Implemented Algorithms)?

Firstly I'm not a crypto expert, however I know how to use algorithms that other people have defined before in practical usages, that is, as long as they live up to their promises. The thing is that ...
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2answers
37 views

Can an RSA signature be changed given the public key?

If I were to post on a forum (with potentially malicious administrators) my public RSA key and a small string of text that was signed with the corresponding private key, could someone with access to ...
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0answers
77 views

RSA-1024 vs. DSA-1024: Claim DSA SSH key is much faster to brute force

Does the brute force speed vary significantly between 1024-bit RSA and DSA SSH keys? DSA like gpu keypairs are probably DSA/Elgamal? (Can't find docs) EDIT: The reason I ask is an instructor that "...
7
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1answer
145 views

Manually walking through the signature validation of a certificate

Since I am not too familiar with the Web of Trust and Public Key-Infrastructure I decided to learn about it by following the signing chain of a X.509 certificate issued to CN=*wikipedia.org (Serial ...
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1answer
113 views

Ways to generate symmetric and asymmetric keys

We are using Beaglebone Black based custom board, and want to use hybrid encryption for encrypting firmware file, i.e. symmetric for encryption big firmware file and asymmetric for encrypting ...
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1answer
45 views

Is it safe to generate JWTs using private key?

Currently I'm building a Rails API using ruby-jwt as my access token generator. I choose RS256 (RSA + SHA256) as my algorithm. ruby-jwt uses private key to encode payloads, and uses public key to ...
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0answers
11 views

Does PKCS 1.5 padding make it possible for an attacker to extract the private key or not? Is PKCS 1.5 safe to use in authentication context?

Im currently writing a authentication app based on RSA, for Android that should be impossible to copy, even if you have physical access to a phone without lockscreen/PIN. However, the HSM inside the ...
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1answer
101 views

Preventing someone to generate a public key from a private one? [closed]

From what I read, encryption algorithms such as RSA permits to generate the public key from the private one. Long story short, for a thesis I'm writing, I thought to solve a security issue with users ...
2
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1answer
176 views

Which file encryption algorithm is used by Synology's Cloud Sync feature? [closed]

I'm trying to find out which encryption method is used by a piece of software I use, viz. the 'Cloud Sync' feature of Synology's DSM 6.0 running on a Synology NAS. (Background. This Cloud Sync ...
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1answer
71 views

Storing sensitive, sharable data

I'm building a intranet solution for a company using PHP. One of their desired functionalities is storing payrolls, absence and personal information. They need this to be accessible for the employee ...
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1answer
33 views

Does password protected git public key protect my repository?

When generating my public key for GIT access, I decided to set up a password for it. My push procedure looks like this now: Enter passphrase for key '/c/Users/USERNAME/.ssh/id_rsa': Counting objects: ...
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1answer
57 views

Crypto++ RSA - Encrypt and sign with the same key pair

I have a program A which needs to send messages to several instances of program B (B1, B2, etc...). The messages must be encrypted, and also signed. Which means only Bn instances can decode, and they ...
4
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1answer
70 views

Why use a passphrase for RSA key?

Today I generated my first key pair, so my knowledge here is - so to speak - very limited. On client side I am using Windows and to log in I use PuTTY and I used PuTTYGen to create the keys. Here (...
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0answers
46 views

What is the largest cycle of RSA encryption?

Is there a maximum length of a message before it is impractical to use RSA?
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1answer
114 views

Why doesn't my manual RSA key exchange example work?

I'm trying to "manually" compute how the premaster_secret is computed using the RSA key exchange in TLS 1.2, but can't manage to make numbers meet. I am using Scapy SSL to generate a TLS session: I ...
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1answer
227 views

Is this algorithm really end to end encrypted and secure?

I'm creating an anonymous chat where one of the premises is that the conversations are end to end encrypted. I'm using firebase so all the comunication between the clients and the server is SSL ...
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0answers
30 views

Clarification of RSA Key Exchange (TLS 1.2) and AES for On-Going Message Excahnge

I'm trying to understand the full flow of key exchanges for secure communications. As a potentially incorrect premise, I am under the impression that RSA is a good asymmetric technique for ...
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0answers
62 views

JSON Web Token Security RSA

We are planning to use JWT (JSON Web tokens) in an application project, which is a set of multiple distributed web services allowing SSO authentication (single sign on). So there is a single central ...
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0answers
16 views

Is it ok to use one key pair for my authentication endpoint?

I have an web endpoint that checks user passwords, then issues signed JWT tokens to the client if password matches what we have in the database. The JWT is signed with a RSA private key using RS512. ...
0
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1answer
468 views

Is using “SHA-256 with RSA-2048 Encryption” a secure certificate hashing algorithm?

Is using "SHA-256 with RSA-2048 Encryption" a secure certificate hashing algorithm? I don't think it is. Two examples: nsa.gov [careers site] give.wfp.org
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1answer
123 views

What is the difference between a digital signature and whole message encryption?

I am newbie in information security I am trying to understand the difference between a digital signature and encryption of a message. Lets consider simple example of email message. I understand how ...
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30 views

Using the same public exponent for RSA on multiple machines

I have a system where many machines running the same software work independently of each other with no central server of any kind. A user may wish to speak with another user privately and securely, ...
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1answer
43 views

Non-identified algorithm for RSA decryption in tpm-emulator

While analyzing the source code of tpm-emulator I found that the RSA key decryption uses an algorithm that is unknown to me. The original file with this mystery is located in rsa.c, where the ...
6
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1answer
283 views

Are RSA Key Pairs unique?

I generate RSA key pairs mostly using the following command: ssh-keygen -t rsa -b 4096 -C "someemail@hostname.com" which produces a public-private RSA key pair. If I run this command again and ...
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1answer
43 views

Verify a key was signed by another key

I began using GPG4Win/Kleopatra, the GNU Privacy Guard implementation for Windows. More recently I wanted to verify a download of Qubes OS, for which a guide is offered here. They describe a master ...
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1answer
114 views

Someone logged in server through ssh using my RSA key

I just got the warning message from hosting provider that my server make outcoming traffic 1.5G to provide DDOS attack on someone host, and they disabled my VPS temporarily. When I search through ...
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Why SMIME decryption works with sender and recipient private key?

Im developing an application, that needs to use SMIME encryption and authentication. I've implemented a decryption system, and am currently testing it. I send the emails with another fully working ...
3
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1answer
74 views

Is this good/secure method for client-server communication encryption?

Something came to my mind, and I wonder if this is proper method for client-server communication, and if this method is wide-used. On connection, client generates seed, encrypts it using asymmetric ...
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1answer
112 views

Is webkey a reasonably secure authentication system?

I just created Webkey in the last couple days. It's built to do client-certificate auth without using the (in my opinion unusable) client-cert functionality built into browsers. It would allow single-...
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2answers
239 views

Is the RSA private key useless without the password?

I notice whenever I generate a new gpg key (using pgp) I always have to assign a password to it, which makes perfect sense. But if I'm not mistaken, gpg is based on prime numbers. How is this ...
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19 views

Signature algorithm with ECDH ? can we use RSA or ECDSA ? or ECDSA is compulsory?

I am going through RFC 5656. I want to know if ECDH with RSA is allowed? (I am not SSH ECC compliant).
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1answer
113 views

Why does this key get Base64 encoded prior to use?

I wish to have my server encrypt messages to clients who have each provided the server with an RSA public key, as well as having the clients authenticate their messages to the server using their ...
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1answer
471 views

Can a device be TLS compliant without RSA?

Let's consider an embedded device which supports ECC and some symmetric cryptographic primitives but not the RSA algorithm. Can it be TLS compliant? I think that if the device and the server share a ...
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1answer
79 views

RSA rainbow table

Wouldn't it be possible to create as many as possible key pairs for the RSA encryption and then determine from a public key which the corresponding private key is ?
3
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1answer
213 views

What would be a simple example of an asymmetric encryption function (asymmetric function)?

I am trying to understand RSA encryption but the algorithm seems quite complex. I know that with asymmetric encryption you use a key and a function to encrypt data and a different function to decrypt ...
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1answer
37 views

GPG/Bitcoin usb gadget device

My idea is to take a raspberry pi zero (or any embedded linux board) and shove GPG inside it to encrypt/decrypt/sign data with RSA/ECC (for bitcoin) via USB. Like a USB thing that holds your (...
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1answer
67 views

Minimal working configuration for reasonable security in openssh on Linux [duplicate]

I want to connect from my laptop to home server (both run some Linux; notice I explicitly want my user to be able to become root, in order e.g. to install new software): the server has the following ...
3
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1answer
111 views

How could an attacker read the content of php session variables?

In my PHP code, I am generating an RSA keypair, sending the public key to the visitor and storing the private key in a session variable. Is it possible that an attacker might somehow be able to read ...
70
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3answers
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Will quantum computers render AES obsolete?

This is a spin off from: Use multiple computers for faster brute force Here's at least one source which says that quantum computers are on the way to being able to break RSA in the not too distant ...
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1answer
153 views

CSR with only public key with openssl

So I have been doing my research and haven't found anything specific enough to my problem. As the question title states, I want to make a CSR with only the public key. What I have been able to do is ...
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1answer
148 views

How does RSACryptoServiceProvider generate keys

The documentation for the constructor for RSACryptoServiceProvider states "If no default key is found, a new key is created. This constructor creates an Exchange key pair suitable to encrypt session ...
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33 views

RSA decryption with Private and Cert files

What I have : The cipher message, the plaintext message, and something that could be the RSA Private & Cert. (I can create as many couple ciphered/plaintext as I want) I would like to be able to ...