Chapter 14 Certificates

Certification authorities maintain directory servers with databases of valid and revoked certificates. A directory of certificates that have been revoked before the scheduled expiration is called a CRL (Certificate Revocation List). The ZyXEL Device can check a peer’s certificate against a directory server’s list of revoked certificates. The framework of servers, software, procedures and policies that handles keys is called PKI (public-key infrastructure).

14.1.1 Advantages of Certificates

Certificates offer the following benefits.

•The ZyXEL Device only has to store the certificates of the certification authorities that you decide to trust, no matter how many devices you need to authenticate.

•Key distribution is simple and very secure since you can freely distribute public keys and you never need to transmit private keys.

14.2Self-signed Certificates

You can have the ZyXEL Device act as a certification authority and sign its own certificates.

14.3 Verifying a Certificate

Before you import a trusted CA certificate into the ZyXEL Device, you should verify that you have the actual certificate. This is especially important since the ZyXEL Device also trusts any valid certificate signed by any of the imported trusted CA certificates.

14.3.1 Checking the Fingerprint of a Certificate on Your Computer

A certificate’s fingerprints are message digests calculated using the MD5 or SHA1 algorithms. The following procedure describes how to check a certificate’s fingerprint to verify that you have the actual certificate.

1Browse to where you have the certificate saved on your computer.

2Make sure that the certificate has a “.cer” or “.crt” file name extension.

Figure 95 Certificates on Your Computer

3Double-click the certificate’s icon to open the Certificate window. Click the Details tab and scroll down to the Thumbprint Algorithm and Thumbprint fields.

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ZyXEL NWA-3160 Series User’s Guide