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P-661HNU-Fx User’s Guide
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Certificates
15.1 Overview
The ZyXEL Device can use certificates (also called digital IDs) to authenticate
users. Certificates are based on public-private key pairs. A certificate contains the
certificate owner’s identity and public key. Certificates provide a way to exchange
public keys for use in authentication.
15.1.1 What You Can Do in this Chapter
• Use the Local Certificate screens to view and import the ZyXEL Device’s CA-
signed certificates ( Section 15.2 on page 210 ).
• Use the Trusted CA screens to save the certificates of trusted CAs to the ZyXEL
Device. You can also export the certificates to a computer ( Section 15.2.1 on
page 212 ).
15.1.2 What You Need to Know
The following terms and concepts may help as you read this chapter.
Certification Authorities
A Certification Authority (CA) issues certificates and guarantees the identity of
each certificate owner. There are commercial certification authorities like
CyberTrust or VeriSign and government certification authorities.
Public and Private Keys
When using public-key cryptology for authentication, each host has two keys. One
key is public and can be made openly available; the other key is private and must
be kept secure. Public-key encryption in general works as follows.
1
Tim wants to send a private message to Jenny. Tim generates a public-private key
pair. What is encrypted with one key can only be decrypted using the other.
2
Tim keeps the private key and makes the public key openly available.