Allied Telesis AT-S63 User Manual

Page of 514
Chapter 34: PKI Certificates and SSL
408
Section IX: Management Security
this, and other attacks, PKI provides a means for secure transfer of public 
keys by linking an identity and that identity’s public key in a secure 
certificate.
Caution
Although a certificate binds a public key to a subject to ensure the 
public key’s security, it does not guarantee that the security of the 
associated private key has not been breached. A secure system is 
dependent upon private keys being kept secret, by protecting them 
from malicious physical and virtual access.
Certificates
certificate is an electronic identity document. To create a certificate for a 
subject, a trusted third party (known as the Certification Authority) verifies 
the subject’s identity, binds a public key to that identity, and digitally signs 
the certificate. A person receiving a copy of the certificate can verify the 
Certification Authority’s digital signature and be sure that the public key is 
owned by the identity in it. 
The switch can generate a self-signed certificate but this should only be 
used with an SSL enabled HTTP server, or where third party trust is not 
required.
X.509 Certificates
The X.509 specification specifies a format for certificates. Almost all 
certificates use the X.509 version 3 format, described in RFC 2459, 
Internet X.509 Public Key Infrastructure Certificate and CRL Profile. This 
is the format which is supported by the switch.
An X.509 v3 certificate consists of:
ˆ
A serial number, which distinguishes the certificate from all others 
issued by that issuer. This serial number is used to identify the 
certificate in a Certificate Revocation List, if necessary.
ˆ
The owner’s identity details, such as name, company and address.
ˆ
The owner’s public key, and information about the algorithm with 
which it was produced.
ˆ
The identity details of the organization which issued the certificate.
ˆ
The issuer’s digital signature and the algorithm used to produce it.
ˆ
The period for which the certificate is valid.
ˆ
Optional information is included, such as the type of application with 
which the certificate is intended to be used. 
The issuing organization’s digital signature is included in order to 
authenticate the certificate. As a result, if a certificate is tampered with 
during transmission, the tampering is detected.