plus/minus epsilon

SEAD, the Secure Efficient Ad hoc Distance vector routing protocol, is a recent secure ad-hoc routing protocol designed to use symmetric cryptographic primitives almost exclusively. Relying on symmetric cryptography, rather than asymmetric often requires 3 to 4 orders of magnitude less computation with a negligible increase in storage or network overhead.

Peer-to-peer distributed hash tables have been the subject of a large amount of research because they solve a significant problem in computer science: the secure and efficient distribution of large amounts of data amongst a loose collection of disparate nodes, lacking any centralized authorities or hierarchies.