Red Hat Summit第1章 Public key certificates in Identity Management
X.509 public key certificates are used to authenticate users, hosts and services in Identity Management (IdM). In addition to authentication, X.509 certificates also enable digital signing and encryption to provide privacy, integrity and non-repudiation.
A certificate contains the following information:
- The subject that the certificate authenticates.
- The issuer, that is the CA that has signed the certificate.
- The start and end date of the validity of the certificate.
- The valid uses of the certificate.
- The public key of the subject.
A message encrypted by the public key can only be decrypted by a corresponding private key. While a certificate and the public key it includes can be made publicly available, the user, host or service must keep their private key secret.
1.1. Certificate authorities in IdM
Certificate authorities operate in a hierarchy of trust. In an IdM environment with an internal Certificate Authority (CA), all the IdM hosts, users and services trust certificates that have been signed by the CA. Apart from this root CA, IdM supports sub-CAs to which the root CA has granted the ability to sign certificates in their turn. Frequently, the certificates that such sub-CAs are able to sign are certificates of a specific kind, for example VPN certificates. Finally, IdM supports using external CAs. The table below presents the specifics of using the individual types of CA in IdM.
| Name of CA | Description | Use | Useful links |
|---|---|---|---|
|
The | An integrated CA based on the Dogtag upstream project | Integrated CAs can create, revoke, and issue certificates for users, hosts, and services. | Using the ipa CA to request a new user certificate and exporting it to the client |
| IdM sub-CAs |
An integrated CA that is subordinate to the |
IdM sub-CAs are CAs to which the | Restricting an application to trust only a subset of certificates |
| External CAs | An external CA is a CA other than the integrated IdM CA or its sub-CAs. | Using IdM tools, you add certificates issued by these CAs to users, services, or hosts as well as remove them. | Managing externally signed certificates for IdM users, hosts, and services |
From the certificate point of view, there is no difference between being signed by a self-signed IdM CA and being signed externally.
The role of the CA includes the following purposes:
- It issues digital certificates.
- By signing a certificate, it certifies that the subject named in the certificate owns a public key. The subject can be a user, host or service.
- It can revoke certificates, and provides revocation status via Certificate Revocation Lists (CRLs) and Online Certificate Status Protocol (OCSP).
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