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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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 ...
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73 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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How does a chosen ciphertext attack work on textbook RSA?

I am very new to cryptography and I am confused with something. Here is the homework question I am having trouble with: Write a program to attack the Textbook RSA Encryption Scheme, in order to ...
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188 views

Should SHA-1 be used with RSA-OAEP?

PKCS#1 defines SHA1 as a default hash function and all implementations support this hash function and the mask generation functions based on SHA1. In some implementations you can change the hash ...
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58 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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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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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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131 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 ...
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110 views

Questions on the variations of RSA keys

I've built a simple application that reads in an RSA key, checks the header and starts identifying properties of the RSA key to make sure it is valid (Using child_process in express to run $ ...
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42 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
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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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219 views

How do I find a PKI smart card reader/writer for development (Microsoft .NET)

I would like to learn how to develop software leveraging PKI smart cards. Ideally, I would use Microsoft Base Smart Card CSP, but I really just need the ability to store symmetric and asymmetric keys ...
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300 views

Using given RSA private key without the associated public key

I'm currently following a small game to get more familar with linux and security and got the following task: The password for the next level is stored in /etc/bandit_pass/bandit14 and can only be ...
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84 views

Self-chosen fixed RSA PIN in addition to a Password

I'm using a Junos Pulse Secure Access Service (Juniper Networks), which requires to enter a RSA PIN in addition to the password. I don't know if this is always the case or if it's a custom ...
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75 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 "...
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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 ...
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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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144 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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343 views

Using ECC for PGP-Master Key in combination with Yubikey

I acquired a Yubikey Neo last month. Now I want to use the Smart-Card functionality for PGP. I followed the official guides on the Yubico Website tested it with 2048 RSA Keys and it worked fine. But ...
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103 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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1answer
171 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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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 ...
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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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How do RSA SecureID ® Keys Work?

I have been using RSA SecureID ® Keys for quite some time now (perhaps 10 years), for things such as securely my home banking account online or accessing my company's network of computers from home. ...
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995 views

Why does the linux XRDP module use a 512 bit RSA key?

Why does the linux XRDP module use a 512 bit RSA key? 512 bit RSA keys are broken by now. How can this be safe?
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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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56 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 ...
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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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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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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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217 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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28 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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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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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. ...
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1answer
405 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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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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PKCS#1-1.5 encoding - is there a reason to use 00 in block type?

For encryption block looking like this: EB = 00 || BT || PS || 00 || Data where BT - block type and PS - padding string, I've read that we use three types of BT - 00, 01, 02. Now, since 00 and 01 are ...
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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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Is this RSA/AES combination good?

The team of developers I am part of is trying to develop a safe way to exchange sensitive data between a server and mobile devices. We have come up with the following algorithm: Device generates ...
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1answer
875 views

Determine private key size using public certificate [duplicate]

I have a public certificate in a PEM (.pem) file -----BEGIN CERTIFICATE----- MIICsjCCAZqgAwIBAgIJAMA1YIQ2JLXDMA0GCSqGSIb3DQEBBQUAMBExDzANBgNV ... 29V/R9RZOoSBHDzGPL84wm4qojMuwQ== -----...
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40 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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277 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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Which part is the longest when gerating RSA key pairs?

Whether I use openssll or gnutls's certtool, I end in a single threaded part which take several minutes. When I try to compile the libraries with auto-parallelizer advanced efficient tools. It sill ...
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7k views

New PGP key: RSA/RSA or DSA/Elgamal?

I wanted to create a new PGP key using GPG Keychain Access on my Mac. One of the options was to choose keytype: RSA and RSA DSA and Elgamal RSA (Sign only) DSA (Sign only) I found this Superuser ...
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How much faster does a GPU or FPGA crack an RSA key compared to a CPU?

Are there any significant speed up in time on cracking an RSA key (either brute-force or factoring with general number field sieve) using a GPA or FPGA compared to a CPU? If there is a speed advantage,...
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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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Is it bad that my ed25519 key is so short compared to a RSA key?

I recently generated a new SSH key in the ed25519 format. The public key is only 69 bytes long while my old RSA key is 373 bytes. From my perception ed25519 is the more recent and secure format. So ...
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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 ...
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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 ...