OpenSSL Generate 4096-bit Certificate (Public/Private Key Encryption) with SHA256 Fingerprint
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. You can generate a public-private keypair with the genrsa context (the last number is the keylength in bits): openssl genrsa -out keypair.pem 2048 To extract the public part, use the rsa context: openssl rsa -in keypair.pem -pubout -out publickey.crt Finally, convert the original keypair to. Add your SSH private key to the ssh-agent. If you created your key with a different name, or if you are adding an existing key that has a different name, replace idrsa in the command with the name of your private key file. $ ssh-add /.ssh/idrsa; Add the SSH key to your GitHub account. I am trying to understand the CSR generation process. I create a private key using Openssl tool. Then use the private key in a command to create a CSR. I know that CSR will contain a public key. Sep 12, 2014 Use this command to check that a private key (domain.key) is a valid key: openssl rsa -check -in domain.key. If your private key is encrypted, you will be prompted for its pass phrase. Upon success, the unencrypted key will be output on the terminal. Verify a Private Key Matches a Certificate and CSR.
gencert.sh
# Generate Private Key and Certificate using RSA 256 encryption (4096-bit key) |
openssl req -x509 -newkey rsa:4096 -keyout privatekey.pem -out certificate.pem -days 365 |
# Alternatively, setting the '-newkey' parameter to 'rsa:2048' will generate a 2048-bit key. |
# Generate PKCS#12 (P12) file for cert; combines both key and certificate together |
openssl pkcs12 -export -inkey privatekey.pem -in certificate.pem -out cert.pfx |
# Generate SHA256 Fingerprint for Certificate and export to a file |
openssl x509 -noout -fingerprint -sha256 -inform pem -in certificate.pem >> fingerprint.txt |
# Generate SHA1 Fingerprint for Certificate and export to a file |
#openssl x509 -noout -fingerprint -sha1 -inform pem -in certificate.pem >> fingerprint.txt |
# FYI, it's best practice to use SHA256 instead of SHA1 for better security, but this shows how to do it if you REALLY need to. |
commented Nov 7, 2019
![Key Key](/uploads/1/2/6/0/126061459/602441466.png)
Here's a couple useful links related to this: |
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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.
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.
Openssl Generate Rsa
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
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.
Begin Rsa Private Key
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