A method and system for key certification in a public key infrastructure. The infrastructure has a network formed of a plurality of nodes. Each node has a private and public key pair. The nodes are either or both a certifying node and a certified node. A certifying node provides a digital certificate referring to the public key of a certified node. The digital certificate is signed by the private key of the certifying node. The method includes providing a root public key for a user, the root public key being at any node in the network chosen by the user, and providing a chain of digital certificates from the node with the root public key across the node network to any other node.