
12.1 PKI Overview
The Public Key Infrastructure (PKI) is a system that generates public keys and digital certificates,
and verifies identities of certificate subjects to ensure information security. PKI provides a
certificate management mechanism for the IP Security (IPSec) protocol and Secure Sockets
Layer (SSL) protocol.
Definition
The public key infrastructure (PKI) is a system that generates public keys and digital certificates,
and verifies identities of certificate subjects to ensure information security. PKI issues digital
certificates that bind public keys to respective user identities by means of a certificate authority
(CA).
PKI allows users to easily request, download, and revoke digital certificates. In addition to
issuing digital certificates, the PKI provides other services such as blacklisting to ensure
confidentiality, integrity, non-repudiation, and authentication of data.
l
Confidentiality: Data will not be intercepted by unauthorized users during transmission.
l
Integrity: Data will not be tampered with by unauthorized users during transmission.
l
Non-repudiation: A data sender cannot deny having sent a message or digital signature.
l
Authentication: Communication entities can be identified.
PKI provides information security on insecure networks and private networks. It can also
securely transmit keys between users.
Digital Certificate
A digital certificate is a file that is signed by a certificate authority (CA) and binds a public key
to user identity. The signature of the CA ensures the validity and authority of the digital
certificate. A digital certificate must comply with the ITU-T X.509 standard. Currently, the X.
509 v3 digital certificates are mostly used. A digital certificate contains multiple fields, including
the certificate issuer name, entity public key, signature of the issuing CA, and certificate validity
period.
Three types of digital certificates are described in this section: local certificates, CA certificates,
and self-signed certificates.
l
Local certificate: is signed by a CA to a user.
l
CA certificate: is used to verify a CA's identity.
If multiple CAs exist in the PKI system, a CA hierarchy is formed. At the top of the hierarchy
is a root CA, which has a self-signed certificate.
l
Self-signed certificate: is issued by a PKI device. In a self-signed certificate, the certificate
issuer and subject are the same.
Certificate Revocation List
When a user name is changed, a private key is compromised, or services cease, the certificate
of the user must be revoked to unbind the public key from user identity. In the PKI, a certificate
revocation list (CRL) is used to revoke certificates. After a certificate is revoked, the CA issuing
this certificate needs to publish a CRL to declare that this certificate is invalid. The CRL contains
serial numbers of revoked certificates. A CRL provides a method to verify certificate validity.
Huawei AR1200-S Series Enterprise Routers
Configuration Guide - Security
12 PKI Configuration
Issue 02 (2012-03-30)
Huawei Proprietary and Confidential
Copyright © Huawei Technologies Co., Ltd.
234