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1. Windows Generate Rsa Key Pair
2. Node Generate Rsa Key Pair
3. Javascript Generate Rsa Key Pair Definition
4. Javascript Generate Rsa Key Pair Parameters To Support Ssh Version 2
5. How To Generate Rsa Key Pair

Generating a Secure Shell (SSH) Public/Private Key Pair Several tools exist to generate SSH public/private key pairs. The following sections show how to generate an SSH key pair on UNIX, UNIX-like and Windows platforms. I need to generate a 1024 bit RSA key for one time use (gets discarded after each run) and pass the public key to a remote client. The remote client expects the key to be 'in ASN.1 format as defined in x509'. (I know how to make the private key in the first place with openssl, and then how to extract the public key - both in ascii format.

Contents

• 3. Saving the Keys in Binary Format
• Source Code

1. Introduction

• How to generate public/private key in C#. Asymmetric cryptography also known as public-key encryption uses a public/private key pair to encrypt and decrypt data. In.NET, the RSACryptoServiceProvider and DSACryptoServiceProvider classes are used for asymmetric encryption.
• Jan 24, 2017 2. Generating a Key Pair. First step in creating an RSA Key Pair is to create a KeyPairGenerator from a factory method by specifying the algorithm (“RSA” in this instance): KeyPairGenerator kpg = KeyPairGenerator.getInstance('RSA'); Initialize the KeyPairGenerator with the key size. Use a key size of 1024 or 2048.
• Generating Keys for Encryption and Decryption.; 3 minutes to read +7; In this article. Creating and managing keys is an important part of the cryptographic process. Symmetric algorithms require the creation of a key and an initialization vector (IV). The key must be kept secret from anyone who should not decrypt your data.
• Oct 05, 2007 Generating public keys for authentication is the basic and most often used feature of ssh-keygen. Ssh-keygen can generate both RSA and DSA keys. RSA keys have a minimum key length of 768 bits and the default length is 2048.

Let us learn the basics of generating and using RSA keys in Java.

Java provides classes for the generation of RSA public and private key pairs with the package java.security. You can use RSA keys pairs in public key cryptography.

Public key cryptography uses a pair of keys for encryption. Distribute the public key to whoever needs it but safely secure the private key.

Public key cryptography can be used in two modes:

Encryption: Only the private key can decrypt the data encrypted with the public key.

Authentication: Data encrypted with the private key can only be decrypted with the public key thus proving who the data came from.

2. Generating a Key Pair

First step in creating an RSA Key Pair is to create a KeyPairGeneratorfrom a factory method by specifying the algorithm (“RSA” in this instance):

Initialize the KeyPairGenerator with the key size. Use a key size of 1024 or 2048. Currently recommended key size for SSL certificates used in e-commerce is 2048 so that is what we use here. Generate new bitcoin private key.

Windows Generate Rsa Key Pair

From the KeyPair object, get the public key using getPublic() and the private key using getPrivate().

3. Saving the Keys in Binary Format

Save the keys to hard disk once they are obtained. This allows re-using the keys for encryption, decryption and authentication.

What is the format of the saved files? The key information is encoded in different formats for different types of keys. Here is how you can find what format the key was saved in. On my machine, the private key was saved in PKCS#8 format and the public key in X.509 format. We need this information below to load the keys.

Node Generate Rsa Key Pair

3.1. Load Private Key from File

Javascript Generate Rsa Key Pair Definition

After saving the private key to a file (or a database), you might need to load it at a later time. You can do that using the following code. Note that you need to know what format the data was saved in: PKCS#8 in our case.

Javascript Generate Rsa Key Pair Parameters To Support Ssh Version 2

3.2 Load Public Key from File

Load the public key from a file as follows. The public key has been saved in X.509 format so we use the X509EncodedKeySpec class to convert it.

4. Use Base64 for Saving Keys as Text

Save the keys in text format by encoding the data in Base64. Java 8 provides a Base64 class which can be used for the purpose. Save the private key with a comment as follows:

And the public key too (with a comment):

5. Generating a Digital Signature

As mentioned above, one of the purposes of public key cryptography is digital signature i.e. you generate a digital signature from a file contents, sign it with your private key and send the signature along with the file. The recipient can then use your public key to verify that the signature matches the file contents.

Here is how you can do it. Use the signature algorithm “SHA256withRSA” which is guaranteed to be supported on all JVMs. Use the private key (either generated or load from file as shown above) to initialize the Signatureobject for signing. It is then updated with contents from the data file and the signature is generated and written to the output file. This output file contains the digital signature and must be sent to the recipient for verification.

6. Verifying the Digital Signature

The recipient uses the digital signature sent with a data file to verify that the data file has not been tampered with. It requires access to the sender’s public key and can be loaded from a file if necessary as presented above.

The code below updates the Signature object with data from the data file. It then loads the signature from file and uses Signature.verify() to check if the signature is valid.

And that in a nutshell is how you can use RSA public and private keys for digital signature and verification.

Source Code

Go here for the source code.

RSA Key Generator

How To Generate Rsa Key Pair

This tool generates a RSA PEM key pair

Prerequisites:

• NodeJS:https://nodejs.org/en/download/
• GIT:https://git-scm.com/downloads

Install

Once you have installed NodeJS and GIT on your system, you can download and install this tool with the following commands:

git clone https://github.com/tevix/rsa-key-gen.git

cd rsa-key-gen

npm install

Usage

To generate a key pair run the following command:

node generate

The tool will generate two .pem files, one public key and one private key in the current directory: