Introduction
- Create Rsa Key Openssl
- Openssl Generate Rsa Pkcs8
- Generate Rsa Key Openssl
- Openssl Generate Private Key
- Generate Key With Openssl
- Openssl Rsa Public Key
Nov 06, 2019 It's also possible to generate keys using openssl only: openssl genrsa -out private.pem 2048 openssl rsa -in private.pem -pubout -out. OpenSSL's genpkey utility supports let's you generate RSASSA-PSS keys (you have to set the aglorithm parameter to RSA-PSS) but if it supports RSAES-OAEP keys the documentation certainly makes no indication of that.
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.
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
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
![Generate New Rsa Key Openssl Generate New Rsa Key Openssl](/uploads/1/2/5/8/125874873/242560106.jpg)
Please take into account that Organization Name and Unit Name must not contain the following characters:
< > ~ ! @ # $ % ^ * / ( ) ?.,&
Create Rsa Key Openssl
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.
Next, You Should Also Read:
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.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:
Openssl Generate Rsa Pkcs8
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.
Generate Rsa Key Openssl
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.
Found an issue?
Openssl Generate Private Key
Rietta plans, develops, and maintains applications.
Generate Key With Openssl
Learn more about our services or drop us your email and we'll e-mail you back.