Definitions for "Public Key Infrastructure"
Establishes security policies for a variety of network applications and services (i.e., digital certificates).
A system for securely exchanging information that includes a method for publishing the public keys used in public key cryptography and for keeping track of keys that are no longer valid. Different industry and technical groups are developing PKI technology and the National Institute for Standards and Technology (NIST) in the US is working to make sure those technologies are compatible.
Public Key Infrastructure (PKI) can be used for three things: (i) to prove you are who claim to be (authentication), (ii) to encrypt documents for privacy and (iii) to digitally "sign" documents. PKI is primarily a method of authentication which allows the user to have a "secret" and a "public" key which work as a pair. Only the user knows their secret key, but a message encrypted with that key can only be decrypted using the public key, and crucially vice versa. This means that the really important thing is that you believe that the person claiming to be Pat really is Pat. To achieve this you either need to have issued them with the secret key yourself, or to trust the person who has issued the key. This has led to the creation of companies who will verify that you are who you claim to be and issue a secret key. This system is therefore only as good as the trust in the issuing party (called a trusted third party). It is possible that governments could be the trusted third parties, if ID cards are smart cards which carry ones secret key.
Defines protocols to support online interaction.