Use Openssl To Generate Private Key And Csr

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  2. Private Key Encryption

I am using the following command in order to generate a CSR together with a private key by using OpenSSL: openssl req -new -subj '/CN=sample.myhost.com' -out newcsr.csr -nodes -sha512. Jul 09, 2019 If the Private Key key file is lost, you’ll need to reissue your Certificate. Can I generate a new Private Key for my Certificate if I lose the old one? You can generate a new private key and CSR, or use the automatic CSR and key generation during Certificate reissue (this option is available for all Certificates except for the Multi. While Encrypting a File with a Password from the Command Line using OpenSSL is very useful in its own right, the real power of the OpenSSL library is its ability to support the use of public key cryptograph for encrypting or validating data in an unattended manner (where the password is not required to encrypt) is done with public keys.

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OpenSSL

OpenSSL is a CLI (Command Line Tool) which can be used to secure the server to generate public key infrastructure (PKI) and HTTPS. This article helps you as a quick reference to understand OpenSSL commands which are very useful in common, and for everyday scenarios especially for system administrators.

Certificate Signing Requests (CSRs)

If we want to obtain SSL certificate from a certificate authority (CA), we must generate a certificate signing request (CSR). A CSR consists of mainly the public key of a key pair, and some additional information. Both these components are merged into the certificate whenever we are signing for the CSR.

While generating a CSR, the system will prompt for information regarding the certificate and this information is called as Distinguished Name (DN). The important field in the DN is the Common Name (CN) which should be the FQND (Fully Qualified Domain Name) of the server or the host where we intend to use the certificate with.

The next item in a DN is to provide the additional information about our business or organization. If we purchase an SSL certificate from a certificate authority (CA), it is very important and required that these additional fields like “Organization” should reflect your organization for details.

Here is a general example for the CSR information prompt, when we run the OpenSSL command to generate the CSR.

We can also provide the information by non-interactive answers for the CSR information generation, we can do this by adding the –subj option to any OpenSSL commands that we try to generate or run.

Below is an example for the –subj option where we can provide the information of the organization where we want to use this CSR.

Generating CSRs

In this section, we will cover about OpenSSL commands which are related to generating the CSR. This CSR can be used to request an SSL certificate from a certificate authority.

Generate a Private Key and a CSR

If we want to use HTTPS (HTTP over TLS) to secure the Apache or Nginx web servers (using a Certificate Authority (CA) to issue the SSL certificate). Also, the ‘.CSR’ which we will be generating has to be sent to a CA for requesting the certificate for obtaining CA-signed SSL.

Below is the command to create a 2048-bit private key for ‘domain.key’ and a CSR ‘domain.csr’ from the scratch.

The ‘–newkey rsa:2048’ is the option which we are specifying that the key should be 2048-bit using the RSA algorithm. The ’ –nodes’ option is to specifying that the private key should not be encrypted with a pass phrase. The ‘-new’ option, indicates that a CSR is being generated.

Generate a CSR from an Existing Private Key

Here we will learn about, how to generate a CSR for which you have the private key.

Below is the command to create a new .csr file based on the private key which we already have.

Generate a CSR from an Existing Certificate and Private key

Here we can generate or renew an existing certificate where we miss the CSR file due to some reason. Here, the CSR will extract the information using the .CRT file which we have.

Below is the example for generating –

Where -x509toreq is specified that we are using the x509 certificate files to make a CSR.

Generating a Self-Singed Certificates

Here we will generate the Certificate to secure the web server where we use the self-signed certificate to use for development and testing purpose.

Csr

Here, we generate self-signed certificate using –x509 option, we can generate certificates with a validity of 365 days using –days 365 and a temporary .CSR files are generated using the above information.

Viewing the Certificates Files

Please note that, CSR files are encoded with .PEM format (which is not readable by the humans). This is required to view a certificate. In this section, we can cover the OpenSSL commands which are encoded with .PEM files.

And

Viewing CSR Files Entires

The below command will be used to view the contents of the .CRT files Ex (domain.crt) in the plain text format.

Working with Private Keys

In this section, will see how to use OpenSSL commands that are specific to creating and verifying the private keys.

Create a Private Key

Below is the command to create a password-protected and, 2048-bit encrypted private key file (ex. domain.key) –

Enter a password when prompted to complete the process.

Verify a Private Key

Below is the command to check that a private key which we have generated (ex: domain.key) is a valid key or not

Private Key Bitcoin

If the private key is encrypted, you will be prompted to enter the pass phrase. Upon the successful entry, the unencrypted key will be the output on the terminal.

In this article, we have learnt some commands and usage of OpenSSL commands which deals with SSL certificates where the OpenSSL has lots of features. We will learn more features and usage in the future. I hope this article will help us to understand some basic features of the OpenSSL.

Introduction

A Certificate Signing Request (CSR) is the first step in setting up an SSL Certificate on your website. SSL certificates are provided by Certificate Authorities (CA), which require a Certificate Signing Request (CSR).

This guide will instruct you on how to generate a Certificate Signing Request using OpenSSL.

  • Access to a user account with root or sudo privileges
  • A command line/terminal window
  • If you’re working on a remote server, an established SSH connection to the server
  • OpenSSL needs to be installed on your system to generate the key
  • A text editor, such as nano, to view your key

Open a terminal window. Use your SSH connection to log into your remote server.

Private Key Encryption

Note: If you are working locally, you don’t need an SSH connection. Also, most Linux systems will launch a terminal window by pressing Ctrl-Alt-T or Ctrl-Alt-F1.

Step 2: Create an RSA Private Key and CSR

It is advised to issue a new private key each time you generate a CSR. Hence, the steps below instruct on how to generate both the private key and the CSR.

Make sure to replace your_domain with the actual domain you’re generating a CSR for.

The commands are broken out as follows:

  • openssl – activates the OpenSSL software
  • req – indicates that we want a CSR
  • –new –newkey – generate a new key
  • rsa:2048 – generate a 2048-bit RSA mathematical key
  • –nodes – no DES, meaning do not encrypt the private key in a PKCS#12 file
  • –keyout – indicates the domain you’re generating a key for
  • –out – specifies the name of the file your CSR will be saved as
Private key bitcoin

Note: Use 2048-bit key pairs. The 4096-bit key pairs are more secure, however, they require a lot more server resources.

Your system should launch a text-based questionnaire for you to fill out.

Enter your information in the fields as follows:

  • Country Name – use a 2-letter country code (US for the United States)
  • State – the state in which the domain owner is incorporated
  • Locality – the city in which the domain owner is incorporated
  • Organization name – the legal entity that owns the domain
  • Organizational unit name – the name of the department or group in your organization that deals with certificates
  • Common name – typically the fully qualified domain name (FQDN), i.e. what the users type in a web browser to navigate to your website
  • Email address – the webmaster’s email address
  • Challenge password – an optional password for your key pair

Please take into account that Organization Name and Unit Name must not contain the following characters:

< > ~ ! @ # $ % ^ * / ( ) ?.,&

Once the software finishes, you should be able to find the CSR file in your working directory.

You can also enter the following:

The system should list out all certificate signing requests on the system. The one that matches the domain name you provided in Step 2 appended with the .csr extension is the one you need to look into.

Step 5: Submit the CSR as Part of Your SSL Request

You can open the .csr file in a text editor to find the alphanumeric code that was generated.

Enter the following command:

This text can be copied and pasted into a submittal form to request your SSL certificate from a Certificate Authority.

Make sure you copy the entire text. Some CAs may allow you to simply upload the .csr file you generated. Below is an example of a CSR.

You needn’t send the private key to the CA. Once you get your SSL certificate, the private key on the server will bind with it to encrypt communication.

Now you know how to generate an OpenSSL certificate signing request. Before submitting the CSR to a certificate authority, we recommend verifying the information it holds. Use one of the widely available online CSR decoders.

SSL is a crucial protocol for securing traffic between a website and its visitors. It helps to protect sensitive information online, such as credit card data.

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