Generate A Private Ssl Key

I have purchased the SSL certificate from GoDaddy and i need to install this SSL certificate on siteground server because my site is hosted on siteground. But i am facing the issue with private key because when i try to set up the SSL certificate on Siteground it ask for private key and in am not. An SSL Certificate is a public key verified and signed by a Certificate Authority. You generate a public/private key pair, then from that generate a Certificate Signing Request (which includes the public key), which you send to the CA. It then signs that public key included in the CSR producing the certificate which it sends. OpenSSL generates the private key and CSR files. If you typed the command in step 2 exactly as shown, the files are named server.key and server.csr. You can now send the text in the server.csr file to the signing authority to obtain your certificate. (Do not send the information in your private key!).

Sep 12, 2014 The -nodes option specifies that the private key should not be encrypted with a pass phrase. The -new option, which is not included here but implied, indicates that a CSR is being generated. Generate a CSR from an Existing Private Key. Use this method if you already have a private key that you would like to use to request a certificate from a CA. Crt and key files represent both parts of a certificate, key being the private key to the certificate and crt being the signed certificate. It's only one of the ways to generate certs, another way would be having both inside a pem file or another in a p12 container. All SSL Certificates require a private key to work. The private key is a separate file that’s used in the encryption/decryption of data sent between your server and the connecting clients. A private key is created by you—the certificate owner—when you request your certificate with a Certificate Signing Request (CSR). Set OPENSSLCONF=c: openssl-win32 bin openssl.cfg openssl pkcs12 -in filename.pfx -nocerts -out key.pem openssl rsa -in key.pem -out myserver.key. The private key will be saved as ‘myserver.key’. Carefully protect the private key. Be sure to backup the private key, as there is no means to recover it, should it be lost.

While Encrypting a File with a Password from the Command Line using OpenSSLis very useful in its own right, the real power of the OpenSSL library is itsability to support the use of public key cryptograph for encrypting orvalidating data in an unattended manner (where the password is not required toencrypt) is done with public keys.

The Commands to Run

Generate a 2048 bit RSA Key

You can generate a public and private RSA key pair like this:

openssl genrsa -des3 -out private.pem 2048

That generates a 2048-bit RSA key pair, encrypts them with a password you provideand writes them to a file. You need to next extract the public key file. You willuse this, for instance, on your web server to encrypt content so that it canonly be read with the private key.

Export the RSA Public Key to a File

This is a command that is

openssl rsa -in private.pem -outform PEM -pubout -out public.pem

The -pubout flag is really important. Be sure to include it.

Generate Ssl Private Key Openssl

Next open the public.pem and ensure that it starts with-----BEGIN PUBLIC KEY-----. This is how you know that this file is thepublic key of the pair and not a private key.

To check the file from the command line you can use the less command, like this:

less public.pem

Do Not Run This, it Exports the Private Key

A previous version of the post gave this example in error.

openssl rsa -in private.pem -out private_unencrypted.pem -outform PEM

The error is that the -pubout was dropped from the end of the command.That changes the meaning of the command from that of exporting the public keyto exporting the private key outside of its encrypted wrapper. Inspecting theoutput file, in this case private_unencrypted.pem clearly shows that the keyis a RSA private key as it starts with -----BEGIN RSA PRIVATE KEY-----.

Visually Inspect Your Key Files

It is important to visually inspect you private and public key files to makesure that they are what you expect. OpenSSL will clearly explain the nature ofthe key block with a -----BEGIN RSA PRIVATE KEY----- or -----BEGIN PUBLIC KEY-----.

You can use less to inspect each of your two files in turn:

  • less private.pem to verify that it starts with a -----BEGIN RSA PRIVATE KEY-----
  • less public.pem to verify that it starts with a -----BEGIN PUBLIC KEY-----

The next section shows a full example of what each key file should look like.

The Generated Key Files

The generated files are base64-encoded encryption keys in plain text format.If you select a password for your private key, its file will be encrypted withyour password. Be sure to remember this password or the key pair becomes useless.

The private.pem file looks something like this:

The public key, public.pem, file looks like:

Protecting Your Keys

Depending on the nature of the information you will protect, it’s important tokeep the private key backed up and secret. The public key can be distributedanywhere or embedded in your web application scripts, such as in your PHP,Ruby, or other scripts. Again, backup your keys!

Remember, if the key goes away the data encrypted to it is gone. Keeping aprinted copy of the key material in a sealed envelope in a bank safety depositbox is a good way to protect important keys against loss due to fire or harddrive failure.

Oh, and one last thing.

If you, dear reader, were planning any funny business with the private key that I have just published here. Know that they were made especially for this series of blog posts. I do not use them for anything else.

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If you want to convert your website from HTTP to HTTPS, you need to get a SSL certificate from a valid organization like Verisign or Thawte. You can also generate self signed SSL certificate for testing purpose.

In this article, let us review how to generate private key file (server.key), certificate signing request file (server.csr) and webserver certificate file (server.crt) that can be used on Apache server with mod_ssl.

Key, CSR and CRT File Naming Convention

I typically like to name the files with the domain name of the HTTPS URL that will be using this certificate. This makes it easier to identify and maintain.

Generate A Private Ssl Key
  • Instead of server.key, I use www.thegeekstuff.com.key
  • Instead of server.csr, I use www.thegeekstuff.com.csr
  • Instead of server.crt, I use www.thegeekstuff.com.crt

1. Generate Private Key on the Server Running Apache + mod_ssl

First, generate a private key on the Linux server that runs Apache webserver using openssl command as shown below.

Generate Private Key Ssl

The generated private key looks like the following.

2. Generate a Certificate Signing Request (CSR)

Using the key generate above, you should generate a certificate request file (csr) using openssl as shown below.

3. Generate a Self-Signed SSL Certificate

For testing purpose, you can generate a self-signed SSL certificate that is valid for 1 year using openssl command as shown below.


You can use this method to generate Apache SSL Key, CSR and CRT file in most of the Linux, Unix systems including Ubuntu, Debian, CentOS, Fedora and Red Hat.

4. Get a Valid Trial SSL Certificate (Optional)

Instead of signing it youself, you can also generate a valid trial SSL certificate from thawte. i.e Before spending the money on purchasing a certificate, you can also get a valid fully functional 21 day trial SSL certificates from Thawte. Once this valid certificate works, you can either decide to purchase it from Thawte or any other SSL signing organization.

This step is optional and not really required. For testing purpose, you can always use the self-signed certificate that was generated from the above step.

Go to Thwate trial certificate request page and do the following:

  • Select “SSL Web Server Certificate (All servers)” under the “select your trial certificate”.
  • Do not check the PKCS #7 check-box under the “configure certificate”
  • Copy/Paste the *.csr file that you generate above in the textbox under “certificate signing request (CSR)”
  • Click on next at the bottom, which will give you a 21-day free trial certificate.


Copy/Paste the trial certificate to the www.thegeekstuff.com.crt file as shown below.

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