Converting an SSL Certificate from PEM to P7B Format for Windows

erik · October 11, 2024, 7:26am

Converting an SSL Certificate from PEM to P7B Format for Windows

To convert an SSL certificate from PEM to P7B format suitable for Windows environments, you can use the OpenSSL tool. Below are the detailed steps to achieve this conversion.

Using OpenSSL

OpenSSL is a versatile tool for handling SSL certificates and can easily handle format conversions.

Ensure You Have OpenSSL Installed

Make sure OpenSSL is installed on your system. You can download it from OpenSSL’s official website.
Prepare Your Certificates
- PEM Certificate: Contains the server certificate.
- CA Certificate: Contains the intermediate and root certificates.
Ensure both certificates are in PEM format and properly ordered.
Run the Conversion Command

Use the following OpenSSL command to convert PEM to P7B:
```
openssl crl2pkcs7 -nocrl -certfile your_certificate.pem -certfile CA_cert.pem -out your_certificate.p7b -certfile CA_cert.pem
```
- Parameters Explained:
  - crl2pkcs7: Converts CRL to PKCS#7.
  - -nocrl: Omits the CRL from the output.
  - -certfile: Specifies the certificate files to include.
  - -out: Specifies the output file in P7B format.
Verify the P7B File

After conversion, verify that the .p7b file contains the necessary certificates by opening it with a text editor. It should display the certificates enclosed within:
```
-----BEGIN PKCS7-----
...
-----END PKCS7-----
```

Alternative Method: Using Internet Explorer

If you prefer a graphical interface, you can use Internet Explorer to convert your PEM certificate to P7B format.

Import the PEM Certificate
- Open Internet Explorer.
- Navigate to Tools > Internet Options > Content tab.
- Click on Certificates > Import.
- Follow the Certificate Import Wizard to import your PEM certificate, ensuring you include the entire certificate chain.
Export as P7B
- After importing, go back to Certificates.
- Select the “Other People” tab or the appropriate store.
- Choose your SSL certificate and click Export.
- In the export wizard, select “Cryptographic Message Syntax Standard PKCS #7 Certificate” and check “Include all certificates in the certification path if possible.”
- Save the file with a .p7b extension.

Common OpenSSL Commands for Certificate Conversion

Here are some additional OpenSSL commands that might be useful for various conversion needs:

Convert PEM to DER:

openssl x509 -outform der -in certificate.pem -out certificate.der

Convert DER to PEM:

openssl x509 -inform der -in certificate.der -out certificate.pem

Convert P7B to PEM:

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.pem

Convert PFX to PEM:

openssl pkcs12 -in certificate.pfx -out certificate.pem -nodes

Tips

Include All Certificates: When converting to P7B, ensure you include all intermediate and root certificates to maintain the certificate chain.
Private Keys: P7B files do not contain private keys. Ensure your private key remains secure and separate.

By following these steps, you can efficiently convert your SSL certificate from PEM to P7B format, making it compatible with Windows servers and applications.

Citations:
[1] Convert your SSL - Convert SSL into Different Formats
[2] SSL Converter | LeaderSSL
[3] How to convert a (PEM) X509 cert to PKCS#7 (.p7b) format?
[4] How to convert a certificate into the appropriate format

erik · October 11, 2024, 7:27am

SSL Cert online convertor

PEM Format

The PEM format is the most common format that Certificate Authorities issue certificates in. PEM certificates usually have extensions such as .pem, .crt, .cer, and .key. They are Base64 encoded ASCII files and contain “-----BEGIN CERTIFICATE-----” and “-----END CERTIFICATE-----” statements. Server certificates, intermediate certificates, and private keys can all be put into the PEM format.

Apache and other similar servers use PEM format certificates. Several PEM certificates, and even the private key, can be included in one file, one below the other, but most platforms, such as Apache, expect the certificates and private key to be in separate files.

DER Format

The DER format is simply a binary form of a certificate instead of the ASCII PEM format. It sometimes has a file extension of .der but it often has a file extension of .cer so the only way to tell the difference between a DER .cer file and a PEM .cer file is to open it in a text editor and look for the BEGIN/END statements. All types of certificates and private keys can be encoded in DER format. DER is typically used with Java platforms. The SSL Converter can only convert certificates to DER format. If you need to convert a private key to DER, please use the OpenSSL commands on this page.

PKCS#7/P7B Format

The PKCS#7 or P7B format is usually stored in Base64 ASCII format and has a file extension of .p7b or .p7c. P7B certificates contain “-----BEGIN PKCS7-----” and “-----END PKCS7-----” statements. A P7B file only contains certificates and chain certificates, not the private key. Several platforms support P7B files including Microsoft Windows and Java Tomcat.

PKCS#12/PFX Format

The PKCS#12 or PFX format is a binary format for storing the server certificate, any intermediate certificates, and the private key in one encryptable file. PFX files usually have extensions such as .pfx and .p12. PFX files are typically used on Windows machines to import and export certificates and private keys.

When converting a PFX file to PEM format, OpenSSL will put all the certificates and the private key into a single file. You will need to open the file in a text editor and copy each certificate and private key (including the BEGIN/END statements) to its own individual text file and save them as certificate.cer, CACert.cer, and privateKey.key respectively.

OpenSSL Commands to Convert SSL Certificates on Your Machine

It is highly recommended that you convert to and from .pfx files on your own machine using OpenSSL so you can keep the private key there. Use the following OpenSSL commands to convert SSL certificate to different formats on your own machine:

OpenSSL Convert PEM

Convert PEM to DER

openssl x509 -outform der -in certificate.pem -out certificate.der

Convert PEM to P7B

openssl crl2pkcs7 -nocrl -certfile certificate.cer -out certificate.p7b -certfile CACert.cer

Convert PEM to PFX

openssl pkcs12 -export -out certificate.pfx -inkey privateKey.key -in certificate.crt -certfile CACert.crt

OpenSSL Convert DER

Convert DER to PEM

openssl x509 -inform der -in certificate.cer -out certificate.pem

OpenSSL Convert P7B

Convert P7B to PEM

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer

Convert P7B to PFX

openssl pkcs7 -print_certs -in certificate.p7b -out certificate.cer

openssl pkcs12 -export -in certificate.cer -inkey privateKey.key -out certificate.pfx -certfile CACert.cer

OpenSSL Convert PFX

Convert PFX to PEM

openssl pkcs12 -in certificate.pfx -out certificate.cer -nodes