PKI simply explained is a public key infrastructure that enables secure data exchange in computer-based communication. PKI certificates can encrypt computer-based communication. For this purpose, private and public keys are issued, distributed and checked.

The PKI abbreviation stands for Public Key Infrastructure and enables secure data exchange in a public network. This is because messages can be digitally signed and encrypted using the PKI certificate. The sender requires the recipient's public key. Digital certificates help to confirm the authenticity of this key. The KPI certificate is in turn protected by a digital signature. The authenticity of the signature can be verified using the public key.

A PKI Infrastructure can be requested from a registration authority (RA for short). For approval, the accuracy of the data in the desired certificate is checked. If everything fits, a certification authority (CA for short) provides the certificate and signs it. The PKIs are stored in an associated central directory in order to index keys. A certificate management system provides access to stored certificates. The certificate policy allows outsiders to analyze the trustworthiness of the PKI when it is requested. For larger companies, it may be worthwhile setting up a PKI instead of purchasing it from a PKI service provider. PKI software for operating the certification authority (CA) is always at the heart of a PKI setup.

The meaning of PKI is a public key infrastructure - in the sense of a digital signature and a hierarchy of digital certificates as an electronic ID document. Public key infrastructures are created so that certificates can be exchanged without the communication partners knowing each other personally beforehand. One PKI is used to verify the authenticity of the electronic document and a second PKI is used to protect the fingerprints on the electronic ID document. However, the certificates are only valid for a limited time.

If a large company sets up its own PKI, the certificates for employees are usually issued stored on chip cards. This PKI card becomes the company ID for various login processes in the sense of a single sign-on system. A card management system can then be used to issue or revoke cards and certificates as well as any replacement cards.