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Configuring PKI
Overview
The Public Key Infrastructure (PKI) is a general security infrastructure used to provide information security
through public key technologies.
PKI, also called asymmetric key infrastructure, uses a key pair to encrypt and decrypt the data. The key
pair consists of a private key and a public key. The private key must be kept secret but the public key
needs to be distributed. Data encrypted by one of the two keys can only be decrypted by the other.
A key problem with PKI is how to manage the public keys. PKI employs the digital certificate mechanism
to solve this problem. The digital certificate mechanism binds public keys to their owners, helping
distribute public keys in large networks securely.
With digital certificates, the PKI system provides network communication and e-commerce with security
services such as user authentication, data non-repudiation, data confidentiality, and data integrity.
HP's PKI system provides certificate management for Secure Sockets Layer (SSL).
PKI terms
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Digital certificate
A digital certificate is a file signed by a certificate authority (CA) for an entity. It includes mainly the
identity information of the entity, the public key of the entity, the name and signature of the CA,
and the validity period of the certificate. The signature of the CA ensures the validity and authority
of the certificate. A digital certificate must comply with the international standard of ITU-T X.509.
The most common standard is X.509 v3.
This document discusses two types of certificates: local certificate and CA certificate. A local
certificate is a digital certificate signed by a CA for an entity. A CA certificate is the certificate of
a CA. If multiple CAs are trusted by different users in a PKI system, the CAs will form a CA tree with
the root CA at the top level. The root CA has a CA certificate signed by itself and each lower level
CA has a CA certificate signed by the CA at the next higher level.
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CRL
An existing certificate might need to be revoked when, for example, the username changes, the
private key leaks, or the user stops the business. Revoking a certificate removes the binding of the
public key with the user identity information. In PKI, the revocation is made through certificate
revocation lists (CRLs). Whenever a certificate is revoked, the CA publishes one or more CRLs to
show all certificates that have been revoked. The CRLs contain the serial numbers of all revoked
certificates and provide an effective way for checking the validity of certificates.
A CA might publish multiple CRLs when the number of revoked certificates is so large that
publishing them in a single CRL might degrade network performance. A CA uses CRL distribution
points to indicate the URLs of these CRLs.
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CA policy
A CA policy is a set of criteria that a CA follows in processing certificate requests, issuing and
revoking certificates, and publishing CRLs. Usually, a CA advertises its policy in the form of
certification practice statement (CPS). A CA policy can be acquired through out-of-band means
