Note: Many topics at this site are reduced versions of the text in "The Encyclopedia of Networking and Telecommunications." Search results will not be as extensive as a search of the book's CD-ROM.

A public-key infrastructure (PKI) is a full system for creating and managing public keys used for encrypting data and exchanging those keys among users. A PKI may be installed on an enterprise network, or it may be available in the public environment. A PKI is a complete system for managing keys that includes policies and working procedures.

PKI is about distributing keys in a secure way. Whitfield Diffie and Martin Hellman developed the concept of asymmetric public-key cryptography in 1976, but it was RSA (Rivest, Shamir, Adleman) Data Systems that turned it into a workable and commercial system. Today, RSA is the most popular public-key scheme.

This topic continues in "The Encyclopedia of Networking and Telecommunications" with a discussion of the following:

• Key distribution problems and solutions
• PKI history and development
• Key generation and distribution techniques
• Diffie/Hellman techniques
• Digital signing and certificates
• Building trust and certificate authorities
• PKI structure and services
• X.509 and the IETF PKIX (Public-Key Infrastructure X.509)
• SPKI (Simple PKI)
• PKCS (Public-Key Cryptography Standards)