ZyXEL Communications NWA-1100 User Manual
Chapter 12 Certificate Screen
ZyXEL NWA-1100 User’s Guide
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12.5.1 Private-Public Certificates
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 and can be made openly available. The other key is private and must be kept secure.
These keys work like a handwritten signature (in fact, certificates are often referred to as
“digital signatures”). Only you can write your signature exactly as it should look. When
people know what your signature looks like, they can verify whether something was signed by
you, or by someone else. In the same way, your private key “writes” your digital signature and
your public key allows people to verify whether data was signed by you, or by someone else.
This process works as follows.
“digital signatures”). Only you can write your signature exactly as it should look. When
people know what your signature looks like, they can verify whether something was signed by
you, or by someone else. In the same way, your private key “writes” your digital signature and
your public key allows people to verify whether data was signed by you, or by someone else.
This process works as follows.
1 Tim wants to send a message to Jenny. He needs her to be sure that it comes from him,
and that the message content has not been altered by anyone else along the way. Tim
generates a public key pair (one public key and one private key).
generates a public key pair (one public key and one private key).
2 Tim keeps the private key and makes the public key openly available. This means that
anyone who receives a message seeming to come from Tim can read it and verify
whether it is really from him or not.
whether it is really from him or not.
3 Tim uses his private key to sign the message and sends it to Jenny.
4 Jenny receives the message and uses Tim’s public key to verify it. Jenny knows that the
4 Jenny receives the message and uses Tim’s public key to verify it. Jenny knows that the
message is from Tim, and that although other people may have been able to read the
message, no-one can have altered it (because they cannot re-sign the message with Tim’s
private key).
message, no-one can have altered it (because they cannot re-sign the message with Tim’s
private key).
5 Additionally, Jenny uses her own private key to sign a message and Tim uses Jenny’s
public key to verify the message.
12.5.2 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. You can use the ZyXEL Device to generate
certification requests that contain identifying information and public keys and then send the
certification requests to a certification authority.
certificate owner. There are commercial certification authorities like CyberTrust or VeriSign
and government certification authorities. You can use the ZyXEL Device to generate
certification requests that contain identifying information and public keys and then send the
certification requests to a certification authority.
12.5.3 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.
The following procedure describes how to check a certificate’s fingerprint to verify that you
have the actual certificate.
1 Browse to where you have the certificate saved on your computer.
2 Make sure that the certificate has a “.cer” or “.crt” file name extension.
2 Make sure that the certificate has a “.cer” or “.crt” file name extension.
Figure 56 Certificates on Your Computer