A.2. Certification Authorities
A.2.1. Introduction to Certificate Authorities
A CA consists of a set of tools for generating and managing certificates and a database that contains all of the generated certificates. When setting up a system, it is important to choose a suitable CA that is sufficiently secure for your requirements.
There are two types of CA you can use:
- commercial CAs are companies that sign certificates for many systems.
- private CAs are trusted nodes that you set up and use to sign certificates for your system only.
A.2.2. Commercial Certification Authorities
There are several commercial CAs available. The mechanism for signing a certificate using a commercial CA depends on which CA you choose.
Advantages of commercial CAs
An advantage of commercial CAs is that they are often trusted by a large number of people. If your applications are designed to be available to systems external to your organization, use a commercial CA to sign your certificates. If your applications are for use within an internal network, a private CA might be appropriate.
Criteria for choosing a CA
Before choosing a commercial CA, consider the following criteria:
- What are the certificate-signing policies of the commercial CAs?
- Are your applications designed to be available on an internal network only?
- What are the potential costs of setting up a private CA compared to the costs of subscribing to a commercial CA?
A.2.3. Private Certification Authorities
Choosing a CA software package
If you want to take responsibility for signing certificates for your system, set up a private CA. To set up a private CA, you require access to a software package that provides utilities for creating and signing certificates. Several packages of this type are available.
OpenSSL software package
One software package that allows you to set up a private CA is OpenSSL, http://www.openssl.org. The OpenSSL package includes basic command line utilities for generating and signing certificates. Complete documentation for the OpenSSL command line utilities is available at http://www.openssl.org/docs.
Setting up a private CA using OpenSSL
To set up a private CA, see the instructions in Section A.5, “Creating Your Own Certificates”.
Choosing a host for a private certification authority
Choosing a host is an important step in setting up a private CA. The level of security associated with the CA host determines the level of trust associated with certificates signed by the CA.
If you are setting up a CA for use in the development and testing of Red Hat JBoss A-MQ applications, use any host that the application developers can access. However, when you create the CA certificate and private key, do not make the CA private key available on any hosts where security-critical applications run.
If you are setting up a CA to sign certificates for applications that you are going to deploy, make the CA host as secure as possible. For example, take the following precautions to secure your CA:
- Do not connect the CA to a network.
- Restrict all access to the CA to a limited set of trusted users.
- Use an RF-shield to protect the CA from radio-frequency surveillance.