How to Extract Certificate and Private Key from PFX File

Key Takeaways

• This blog article teaches how to extract a certificate and private key from a PFX file using OpenSSL commands on Windows.
• A PFX file is a file that contains a certificate and its private and public keys in a single file. It is used to store and transfer secure information over the internet, such as SSL certificates for websites.
• To extract the certificate and private key from a PFX file, you need to use the OpenSSL command line tool with the “pkcs12” command and specify the input and output file names and options.

Problem

Sometimes, you may need to extract the certificate and private key from a PFX file for various purposes, such as installing them on a different server, verifying their validity, or converting them to other formats. In this article, we will show you how to extract a certificate and private key from a PFX file using OpenSSL commands on Windows.

Prerequisites

Before you begin, you will need the following:

• A PFX file that you want to extract the certificate and private key from. You can create a PFX file using the Certificate Export Wizard in Windows or the OpenSSL command line tool.
• The password that protects the PFX file. You will need to enter this password when you run the OpenSSL commands to extract the files.
• The OpenSSL software installed on your Windows machine.

Steps to Extract a Certificate and Private Key from a PFX File

Step 1: To extract a certificate and private key from a PFX file, you will need to use the OpenSSL command line tool. You can open the OpenSSL command prompt by clicking on Start, typing “cmd” in the search box, and pressing Enter.

Step 2: Navigate to the folder where your PFX file is located using the “cd” command. For example, if your PFX file is in the C:\Users\username\Desktop folder, you can type:

cd C:\Users\username\Desktop

Once you are in the folder where your PFX file is located, you can run the following commands to extract the certificate and private key from the PFX file.

Step 3: To extract the private key from the PFX file, you will need to use the “pkcs12” command with the “-in” option to specify the input PFX file, the “-nocerts” option to exclude the certificate from the output, the “-out” option to specify the output file name, and the “-nodes” option to avoid encrypting the private key. For example, if your PFX file is named “mycert.pfx” and you want to save the private key as “mykey.pem”, you can type:

openssl pkcs12 -in mycert.pfx -nocerts -out mykey.pem -nodes

Step 4: You will be prompted to enter the password for the PFX file.

Step 5: After you enter the password, the private key will be extracted and saved as “mykey.pem” in the same folder as the PFX file.

Step 6: You can open the “mykey.pem” file with a text editor and see the private key in the PEM format, which starts with “—–BEGIN PRIVATE KEY—–” and ends with “—–END PRIVATE KEY—–”.

Step 7: To extract the certificate from the PFX file, you will need to use the “pkcs12” command with the “-in” option to specify the input PFX file, the “-nokeys” option to exclude the private key from the output, and the “-out” option to specify the output file name. For example, if your PFX file is named “mycert.pfx” and you want to save the certificate as “mycert.pem”, you can type:

openssl pkcs12 -in mycert.pfx -nokeys -out mycert.pem

Step 8: You will be prompted to enter the password for the PFX file.

Step 9: After you enter the password, the certificate will be extracted and saved as “mycert.pem” in the same folder as the PFX file.

Step 10: You can open the “mycert.pem” file with a text editor and see the certificate in the PEM format, which starts with “—–BEGIN CERTIFICATE—–” and ends with “—–END CERTIFICATE—–”.

Frequently Asked Questions (FAQs)

Question: How to Use the Extracted Certificate and Private Key

Answer: After you have extracted the certificate and private key from the PFX file, you can use them for various purposes, such as:

• Installing them on a different server that requires separate files for the certificate and private key, such as Apache or Nginx.
• Verifying the validity and details of the certificate and private key using the OpenSSL commands “x509” and “rsa”.
• Converting them to other formats, such as DER, CRT, or CER, using the OpenSSL commands “x509” and “pkcs12”.
• Creating a new PFX file with a different password or name using the OpenSSL command “pkcs12”.

Question: What is the difference between a PFX file and a PEM file?

Answer: A PFX file is a file that contains a certificate and its private and public keys in a single file. It is also known as a PKCS#12 file, which stands for Public Key Cryptography Standards #12. A PFX file is usually password-protected and can be used to store and transfer secure information over the internet, such as SSL certificates for websites.

A PEM file is a file that contains a certificate or a private key in a text format. It is also known as a Privacy-Enhanced Mail file, which is a standard for secure email communication. A PEM file can be easily read and edited with a text editor and can be used to store and transfer certificates and keys separately.

Question: How can I view the contents of a PFX file?

Answer: You can view the contents of a PFX file using the OpenSSL command line tool. You can open the OpenSSL command prompt by clicking on Start, typing “cmd” in the search box, and pressing Enter. Then, navigate to the folder where your PFX file is located using the “cd” command. For example, if your PFX file is in the C:\Users\username\Desktop folder, you can type:

cd C:\Users\username\Desktop

Once you are in the folder where your PFX file is located, you can run the following command to view the contents of the PFX file:

openssl pkcs12 -in mycert.pfx -info

You will be prompted to enter the password for the PFX file. After you enter the password, you will see the information about the certificate and the private key in the PFX file, such as the subject, issuer, serial number, modulus, exponent, and signature.

Question: How can I create a PFX file from a certificate and a private key?

Answer: You can create a PFX file from a certificate and a private key using the OpenSSL command line tool. You can open the OpenSSL command prompt by clicking on Start, typing “cmd” in the search box, and pressing Enter. Then, navigate to the folder where your certificate and private key files are located using the “cd” command. For example, if your certificate file is named “mycert.pem” and your private key file is named “mykey.pem” and they are in the C:\Users\username\Desktop folder, you can type:

cd C:\Users\username\Desktop

Once you are in the folder where your certificate and private key files are located, you can run the following command to create a PFX file from them:

openssl pkcs12 -export -out mycert.pfx -inkey mykey.pem -in mycert.pem

You will be prompted to enter a password to protect the PFX file. After you enter the password, a PFX file named “mycert.pfx” will be created in the same folder as the certificate and private key files. You can use this PFX file to store and transfer your certificate and keys as a single file.

Summary

In this article, we have learned how to extract a certificate and private key from a PFX file using OpenSSL commands on Windows. We have also learned how to use the extracted files for various purposes, such as installing them on a different server, verifying their validity, or converting them to other formats. We have also answered some frequently asked questions about PFX and PEM files.

Disclaimer: This article is for informational purposes only and does not constitute professional advice. The author and the publisher are not liable for any damages or losses that may result from the use of the information or commands in this article. The user is responsible for complying with any laws or regulations that may apply to the use of OpenSSL or PFX files. The user is also responsible for protecting the security and privacy of their certificate and keys and should not share them with anyone.