Understanding Public-Key Infrastructure: Concepts, Standards, and Deployment Considerations

Services of Public–Key Cryptography

The discovery of public–key cryptography has made a number of services available, some of which were either unknown or unachievable with symmetric ciphers. This section highlights some of the more important and/or more interesting of these services.

Security between Strangers

One of the driving motivations behind public–key cryptography was the inherent difficulty of enabling secure communication between strangers in a symmetric cipher environment. In particular, given the difficulty of computing the private key even if all other details of the cipher are known, it is possible in such a system to take the public key and disseminate it widely. For example, this key can be stored in a public repository (at ...