Multiple CA Certificates in a Single File

This section provides a tutorial example on how to store multiple root CA certificates in a single PEM file to be used by the OpenSSL module as the 'cafile' SSL context option.

Fixing the error occurred in the previous tutorial is not very hard. Here is what I did:

1. Run Firefox 3 and go to https://www.google.com/accounts/ServiceLogin.

2. Click the Lock icon on the right bottom corner of the browser window.

3. Click "View Certificate" button and go to the "Details" tab.

4. Select the root certificate, "Class 3 Public Primary Certification Authority", in the Certificate Hierarchy section and click "Export..." button.

5. Save the root certificate in "CA_for_Google.crt" using the "X.509 Certificate (PEM) format.

6. Concatenet CA_for_Google.crt to the end of CA_Bundle.crt using a text editor:

CA certificate for https://login.yahoo.com
-----BEGIN CERTIFICATE-----
MIICWjCCAcMCAgGlMA0GCSqGSIb3DQEBBAUAMHUxCzAJBgNVBAYTAlVTMRgwFgYD
...
-----END CERTIFICATE-----

CA certificate for https://www.google.com/accounts/ServiceLogin
-----BEGIN CERTIFICATE-----
MIICPDCCAaUCEHC65B0Q2Sk0tjjKewPMur8wDQYJKoZIhvcNAQECBQAwXzELMAkG
...
-----END CERTIFICATE-----

7. Run the test script again:

C:\herong>\local\php\php OpenSSL_HTTPS_file_get_contents_with_CA.php 
   https://www.google.com/accounts/ServiceLogin

<html>
<style type="text/css">
  <!--
  body { font-family: arial,sans-serif; background-color: #fff; ...
  td {font-family: arial, sans-serif;}
  .c { width: 4; height: 4; }
  a:link { color: #00c; }
...

The output looks good. Now I know that 'cafile' => 'CA_Bundle.crt' SSL context option can be used for multiple HTTPS servers with multiple CA certificates concatenated in a single file using the PEM format.

Last update: 2011.

Table of Contents

 About This Book

 Introduction of PKI (Public Key Infrastructure)

 Introduction of HTTPS (Hypertext Transfer Protocol Secure)

 Using HTTPS with IE (Internet Explorer) 10

 Using HTTPS with Chrome 40

 Using HTTPS with Firefox 35

 Perl Scripts Communicating with HTTPS Servers

PHP Scripts Communicating with HTTPS Servers

 Configuring PHP OpenSSL on Windows

 Testing OpenSSL with file_get_contents()

 OpenSSL Configuration Errors

 SSL Context Options for OpenSSL

 Asking OpenSSL to Verify Server's Certificate

 OpenSSL Failing to Verify Server's Certificate

Multiple CA Certificates in a Single File

 Testing OpenSSL with fopen()

 Java Programs Communicating with HTTPS Servers

 Certificate Stores and Certificate Console

 .NET Programs Communicating with HTTPS Servers

 CAcert.org - Root CA Offering Free Certificates

 PKI CA Administration - Issuing Certificates

 Digital Signature - Microsoft Word 2007

 Digital Signature - OpenOffice.org 3

 S/MIME and Email Security

 PKI (Public Key Infrastructure) Terminology

 Outdated Tutorials

 References

 PDF Printing Version